TY - CHAP A1 - Schwenk, C. A1 - Rethmeier, M. A1 - Dilger, Klaus A1 - Michailov, Vesselin T1 - Schweißsimulation im Fahrzeugbau - Möglichkeiten, Grenzen und Herausforderungen T2 - Schweißen und Schneiden 2005, Vorträge der gleichnamigen Großen Schweißtechnischen Tagung in Essen vom 12. bis 14. September 2005 Y1 - 2005 SN - 3-87155-695-5 SP - 353 EP - 358 PB - DVS-Verl. CY - Düsseldorf ER - TY - CHAP A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Simulation der Gefügeumwandlungen mit der STAAZ-Methode T2 - 23. CAD-FEM Users Meeting, 08.-10. November 2005, Bonn Y1 - 2005 N1 - CD-ROM-Ausgabe PB - CAD-FEM GmbH CY - Grafing bei München ER - TY - CHAP A1 - Brand, M. A1 - Michailov, Vesselin T1 - FE-Welding Simulation and Distorsion Measurement during Welding using optical Object Grating Method T2 - Mathematical modelling of weld phenomena 7, papers presented at the Seventh International Seminar 'Numerical Analysis of Weldability' held 2003 Schloss Seggau near Graz, Austria Y1 - 2005 SN - 3-901351-99-X SP - 763 EP - 778 PB - Techn. Univ. CY - Graz ER - TY - CHAP A1 - Michailov, Vesselin A1 - Staudtaus, M. A1 - Rethmeier, M. T1 - Numerical MIG-Welding Simulation of Magnesium Alloys T2 - Mathematical modelling of weld phenomena 7, papers presented at the Seventh International Seminar 'Numerical Analysis of Weldability' held 2003 at Schloss Seggau near Graz, Austria Y1 - 2005 SN - 3-901351-99-X SP - 77 EP - 89 PB - Techn. Univ. CY - Graz ER - TY - CHAP A1 - Stadtaus, Marc A1 - Dilger, Klaus A1 - Michailov, Vesselin T1 - Numerical Simulation of Tekken and Modified CTS-Test for the Prediction of Cold Cracking Susceptibility T2 - Mathematical modelling of weld phenomena 7, papers presented at the Seventh International Seminar 'Numerical Analysis of Weldability' held 2003 at Schloss Seggau near Graz, Austria Y1 - 2005 SN - 3-901351-99-X SP - 875 EP - 891 PB - Techn. Univ. CY - Graz ER - TY - CHAP A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin ED - Cerjak, Horst-Hannes T1 - Thermomechanical Numerical Simulation with the Maximum Temperature Austenisation Cooling Time Model (STAAZ) T2 - Mathematical modelling of weld phenomena KW - thermomechanical numerical simulation KW - thermomechanical KW - simulation KW - welding KW - fügen KW - schweißen KW - Fügetechnik Y1 - 2007 SN - 978-3-902465-69-6 PB - Verl. der Techn. Univ. Graz CY - Graz ER - TY - CHAP A1 - Stadtaus, Marc A1 - Doynov, Nikolay A1 - Michailov, Vesselin ED - Cerjak, Horst-Hannes T1 - Investigation of the Modified CTS-Test for the Prediction of Cold Cracking Susceptibility by Numerical Models T2 - Mathematical modelling of weld phenomena 8 KW - CTS-Test KW - cold cracking susceptibility KW - numerical models KW - Kaltriss KW - numerische Modelle KW - welding KW - schweißen KW - fügen KW - Fügetechnik Y1 - 2007 SN - 978-3-902465-69-6 PB - Verl. der Techn. Univ. Graz CY - Graz ER - TY - CHAP A1 - Karkhin, Victor A. A1 - Levchenko, A. M. A1 - Homich, P. N. A1 - Michailov, Vesselin ED - Cerjak, Horst-Hannes T1 - Computer-Aided Determination of Diffusible Hydrogen in Deposited Weld Metal T2 - Mathematical Modelling of Weld Phenomena 8 KW - computer determination KW - determination KW - diffusible hydrogen KW - hydrogen KW - deposited weld metal KW - welding KW - fügen KW - schweißen KW - Fügetechnik Y1 - 2007 SN - 978-3-902465-69-6 SP - 785 EP - 798 PB - Verl. der Techn. Univ. Graz CY - Graz ER - TY - CHAP A1 - Karkhin, Victor A. A1 - Homich, P. N. A1 - Michailov, Vesselin ED - Cerjak, Horst-Hannes T1 - Models for Volume Heat Sources and Functional-Analytical Technique for Calculating the Temperature Fields in Butt Welding T2 - Mathematical modelling of weld phenomena 8 KW - functional-analytical technique KW - calculating temperature fields KW - temperature fields KW - butt welding KW - welding KW - schweißen KW - fügen KW - Fügetechnik Y1 - 2007 SN - 978-3-902465-69-6 PB - Verl. der Techn. Univ. Graz CY - Graz ER - TY - CHAP A1 - Stapelfeld, Christoph A1 - Doynov, Nikolay A1 - Atanasova, D. A1 - Michailov, Vesselin T1 - Calculation of Welding Distortions in Large Structures Using the Maximum Temperature Model and the Coupled Analytic-Numerical Shrinkage Force Model T2 - ESI Global Forum 2010, 19. - 20. Mai 2010, München KW - welding KW - temperature model KW - model KW - analytic KW - numerical KW - shrinkage force model KW - schweißen KW - fügen KW - simulieren Y1 - 2010 ER - TY - CHAP A1 - Michailov, Vesselin A1 - Stapelfeld, Christoph A1 - Doynov, Nikolay T1 - Verzugsberechnung einer komplexen Struktur mittels eines analytisch-numerischen Hybridmodells T2 - DVS Congress 2010, Große Schweißtechnische Tagung, Studentenkongress, Statusseminar "Schneidtechnik" - Abschlusskolloquium zum AiF-Forschungscluster "Integration des Rührreibschweißens in Fertigungsprozessketten, Nürnberg 27./28. September 2010 KW - Verzugsberechnung KW - berechnung KW - komplexe Struktur KW - analytisch KW - numerisch KW - Hybridmodell KW - model KW - schweißen KW - fügen KW - simulieren Y1 - 2010 SN - 978-3-87155-592-3 SP - 128 EP - 132 PB - DVS Media GmbH CY - Düsseldorf ER - TY - CHAP A1 - Schleuß, Leander A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Widerstandspunktschweißen strukturierter Bleche - Schweißbereiche, Prüfung, Anwendung KW - Widerstandspunktschweißen KW - strukturiert KW - Bleche KW - Schweißbereich KW - Prüfung KW - Anwendung KW - schweißen KW - fügen Y1 - 2010 ER - TY - CHAP A1 - Michailov, Vesselin A1 - Ossenbrink, Ralf A1 - Stapelfeld, Christoph T1 - Anwendungsnahe Schweißsimulation komplexer Strukturen KW - Schweißsimulation KW - komplexe Struktur KW - Strukturen KW - schweißen KW - fügen KW - simulieren Y1 - 2010 SN - 978-3-87155-290-8 PB - DVS Media GmbH CY - Düsseldorf ER - TY - CHAP A1 - Genchev, Gancho Vladimirov A1 - Doynov, Nikolay A1 - Michailov, Vesselin T1 - Kennlinien zur Festlegung der erforderlichen räumlichen und zeitlichen Diskretisierung bei der thermomechanischen Schweißsimulation KW - thermomechanisch KW - Schweißsimulation KW - schweißen KW - fügen KW - simulieren KW - Simulation Y1 - 2010 ER - TY - CHAP A1 - Michailov, Vesselin A1 - Hantelmann, Cord A1 - Kloshek, Alexander T1 - Impulsrührreibschweißen - ein Verfahren mit neuen Möglichkeiten T2 - Große Schweißtechnische Tagung 2011 Y1 - 2011 SN - 978-3-87155-267-0 SP - 171 EP - 176 PB - DVS Media GmbH CY - Düsseldorf ER - TY - CHAP A1 - Graf, K. A1 - Schleuß, Leander A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Auswirkung von strukturierten Fügepartnern auf geklebte Verbindungen T2 - Große Schweißtechnische Tagung 2011 Y1 - 2011 SN - 978-3-87155-267-0 SP - 472 EP - 477 PB - DVS-Verl. CY - Düsseldorf ER - TY - CHAP A1 - Michailov, Vesselin A1 - Kloshek, Alexander A1 - Doynov, Nikolay T1 - Thermomechanische Simulation geschweißter Mischverbindungen aus Aluminium- und Stahlwerkstoffen T2 - Jahrbuch Schweißtechnik 2012 Y1 - 2011 SN - 978-3-87155-606-7 SP - 173 EP - 184 PB - DVS Media GmbH CY - Düsseldorf ER - TY - CHAP A1 - Genchev, Gancho Vladimirov A1 - Kloshek, Alexander A1 - Michailov, Vesselin T1 - Numerische Simulation der Strömungen in einer Schweißhaube T2 - Die Verbindungs-Spezialisten 2009 Y1 - 2009 SN - 978-3-87155-584-8 PB - DVS-Verl. CY - Düsseldorf ER - TY - GEN A1 - Michailov, Vesselin A1 - Doynov, Nikolay A1 - Stapelfeld, Christoph A1 - Ossenbrink, Ralf T1 - Hybrid Model for Prediction of Welding Distortions in Large Structures T2 - Journal of Frontiers of Materials Science Y1 - 2011 SN - 2095-025X VL - 5 IS - 2 SP - 209 EP - 215 ER - TY - GEN A1 - Fritzsche, Sebastian A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Experimental characterisation of structured sheet metals T2 - Key Engineering Materials Y1 - 2011 SN - 1013-9826 SN - 1662-9795 VL - 473 SP - 404 EP - 411 ER - TY - GEN A1 - Brandl, Erhard A1 - Palm, Frank A1 - Michailov, Vesselin A1 - Viehweger, Bernd A1 - Leyens, Christoph T1 - Mechanical properties of additive manufactured titanium (Ti-6Al-4V) blocks deposited by a solid-state laser and wire T2 - Materials and Design KW - Non-ferrous metals and alloys KW - Mechanical KW - Microstructure Y1 - 2011 SN - 0261-3069 VL - 32 IS - 10 SP - 4665 EP - 4675 ER - TY - GEN A1 - Dreibati, Ossama A1 - Ossenbrink, Ralf A1 - Doynov, Nikolay A1 - Michailov, Vesselin T1 - Physical and numerical simulation of thermo-mechanical properties in the weld heat affected zone of an AlMgSi-alloy T2 - Materials Science Forum Y1 - 2012 SN - 0255-5476 VL - 706-709 SP - 1491 EP - 1496 ER - TY - GEN A1 - Malikov, Viatcheslav A1 - Ossenbrink, Ralf A1 - Viehweger, Bernd A1 - Michailov, Vesselin T1 - Experimental investigation and analytical calculation of the bending force for air bending of structured sheet metals T2 - Advanced Materials Research KW - air bending KW - structured sheet metal KW - bending force Y1 - 2012 SN - 1022-6680 VL - 418-420 SP - 1294 EP - 1300 ER - TY - GEN A1 - Kornienko, Elena A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Corrosion properties of structured sheet metals in salt environment T2 - Engineering Review Y1 - 2011 SN - 1330-9587 VL - 31 IS - 2 SP - 97 EP - 104 ER - TY - GEN A1 - Bandl, Erhard A1 - Michailov, Vesselin A1 - Viehweger, Bernd A1 - Leyens, Christoph T1 - Deposition of Ti-6Al-4V using laser and wire, part II: Hardness and dimensions of single beads T2 - Surface & Coatings Technology Y1 - 2011 SN - 0257-8972 VL - 206 IS - 6 SP - 1130 EP - 1141 ER - TY - GEN A1 - Malikov, Viatcheslav A1 - Ossenbrink, Ralf A1 - Viehweger, Bernd A1 - Michailov, Vesselin T1 - Analytical and numerical calculation of the force and power requirements for air bending of structured sheet metals T2 - Key Engineering Materials KW - air bending, structured sheet metal, simulation Y1 - 2011 U6 - https://doi.org/10.4028/www.scientific.net/KEM.473.602 SN - 1013-9826 VL - Vol. 473 SP - 602 EP - 609 ER - TY - BOOK A1 - Michailov, Vesselin A1 - Doynov, Nikolay A1 - Ossenbrink, Ralf T1 - Sensibilitätsanalyse der thermomechanischen FE-Schweißsimulation KW - FE-Schweißsimulation, Sensibilitätsanalyse, FE-Netz, Wärmequellen, Werkstoffkennwerte Y1 - 2012 UR - http://www.shaker.de/de/content/catalogue/index.asp?lang=de&ID=8&ISBN=978-3-8440-1016-9 SN - 978-3-8440-1016-9 PB - Shaker CY - Aachen ER - TY - GEN A1 - Genchev, Gancho Vladimirov A1 - Dreibati, Ossama A1 - Ossenbrink, Ralf A1 - Doynov, Nikolay A1 - Michailov, Vesselin T1 - Physical and Numerical Simulation of the Heat-affected Zone of Multi-pass Welds T2 - Materials Science Forum N2 - The paper presents a numerical and experimental approach for the quantification of the thermo-mechanical properties in multi-pass weld’s heat affected zone (HAZ) of low alloy steel “S355J2+N”. First, the characteristic temperature cycles for multi-pass welds were identified by FE temperature field simulations of welding. Based on the identified temperature cycles, the microstructure in the HAZ has been physically simulated with the simulation and testing system Gleeble 3500 to investigate the influence of multi thermal exposure on the thermo-mechanical properties. Thus, the thermo-mechanical material properties including thermal strain and temperature dependent stress strain behaviour as function of peak temperatures and cooling rates have been determined. These material properties were used to calibrate a developed model for numerical prediction of the material properties of multi-pass weld HAZ. KW - welding simulation KW - multi-pass welds KW - thermo-mechanical properties KW - physical simulation, Gleeble Y1 - 2013 UR - www.scientific.net/MSF.762.544 SN - 0255-5476 IS - Vol. 762 SP - 544 EP - 550 ER - TY - CHAP A1 - Genchev, Gancho Vladimirov A1 - Ossenbrink, Ralf A1 - Doynov, Nikolay A1 - Michailov, Vesselin ED - Keßler, Olaf T1 - Gefügeeigenschaften in der Wärmeeinflusszone von Mehrlagenschweißungen aus S355J2+N T2 - Fortschritte in der Metallographie KW - Wärmeeinflusszone der Mehrlagenschweißung KW - experimentelle Werkstoffkennwerte Y1 - 2012 SN - 978-3-88355-392-4 SP - 167 EP - 172 PB - Inventum CY - Bonn ER - TY - THES A1 - Ossenbrink, Ralf T1 - Thermomechanische Schweißsimulation unter Berücksichtigung von Gefügeumwandlungen KW - Schweißsimulation KW - Eigenspannung KW - Laserstrahlschweißen KW - STAAZ-Modell KW - Stahl KW - Umwandlungsplastizität KW - thermomechanische Werkstoffkennwerte Y1 - 2009 SN - 978-3-8322-8131-1 PB - Shaker CY - Aachen ER - TY - CHAP A1 - Ossenbrink, Ralf A1 - Brand, M. A1 - Michailov, Vesselin T1 - Numerische Simulation der Eigenspannungen und des Bauteilverzugs beim Schweißen mit Berücksichtigung des Umwandlungsverhaltens T2 - Große Schweißtechnische Tagung, Schweissen und Schneiden, 2003 KW - Laserstrahlschweißen; Eigenspannung; Verzug; numerische Simulation; thermomechanische Kennwerte Y1 - 2003 SN - 3-87155-683-1 SP - 279 EP - 283 PB - DVS-Verlag CY - Düsseldorf ER - TY - GEN A1 - Michailov, Vesselin A1 - Stadtaus, Marc T1 - Einige Probleme der FE-Simulation zur Wasserstoff- und Stickstoffverteilung beim Schweißen T2 - Zeitschrift für Metallkunde KW - Wasserstoff- und Stickstoffverteilung KW - FE-Simulation des Schweißens Y1 - 2001 SN - 0044-3093 VL - 92 IS - 3 SP - 247 EP - 252 ER - TY - GEN A1 - Zhang, Wei A1 - Doynov, Nikolay A1 - Wolf, Matthias A1 - Dreibati, Ossama A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Investigation of the Thermal Shock Behavior of Ceramic Using a Combination of Experimental Testing and FE-Simulation Methods T2 - Advanced engineering materials N2 - Thermal shock behavior of ceramics plays a decisive role in their broad industrial applications. For enhanced understanding of damage and failure mechanism under thermal shock loading, in the present work, a combination of experimental testing and numerical simulation methods has been used. The thermal shock behavior of the alumina (99.7%) disk samples has been investigated by using a plasma test stand: the bottom of the ceramic disks were locally heated in the center by plasma beam; during the heat treatment the temperature distribution at the top of the sample was recorded with a thermographic system. To characterize the thermal shock resistance, a thermomechanical simulation was subsequently carried out. It calculates the temperature and stress distribution within the ceramic disks. The calculated critical thermal tension stresses are reported, which led to the failure of the ceramic disks under thermal shock loading. The effect of the sample thickness on the temperature and stress distribution is presented. Compared with the experimental results the simulated results show excellent agreement. As conclusion, it is possible to determine the thermal shock behavior of ceramic materials by the combination of experimental testing and numerical simulation. KW - Thermal Shock Behavior KW - Ceramic KW - FE-Simulation KW - Experimental Testing Y1 - 2013 UR - http://www.aem-journal.com U6 - https://doi.org/10.1002/adem.201200241 SN - 1527-2648 VL - 15 IS - 6 SP - 480 EP - 484 ER - TY - CHAP A1 - Doynov, Nikolay A1 - Christov, St. A1 - Michailov, Vesselin A1 - Wohlfahrt, Helmut T1 - Finite Elements Simulation of Multipass Submerged Arc Welding T2 - Mathematical Modelling of Weld Phenomena 6 KW - Multipass Submerged Arc Welding KW - Finite Elements Simulation Y1 - 2002 SN - 978-1-902653-56-3 SP - 651 EP - 669 PB - Maney – IOM CY - London ER - TY - CHAP A1 - Stadtaus, Marc A1 - Michailov, Vesselin A1 - Wohlfahrt, Helmut T1 - Simulation of Weld Shape, Microstructure, Distortion and Residual Stresses for Laser Beam Welding T2 - Mathematical Modelling of Weld Phenomena 6 KW - Laser Beam Welding KW - Simulation of Weld Shape KW - Microstructure KW - Distortion and Residual Stresses Y1 - 2002 SN - 978-1-902653-56-3 SP - 419 EP - 442 PB - Maney – IOM CY - London ER - TY - CHAP A1 - Rethmeier, M. A1 - Stadtaus, Marc A1 - Michailov, Vesselin A1 - Wohlfahrt, Helmut T1 - Numerical Calculation of Temperature Load and Distortion during Welding of Circumferential Weld Seams T2 - Mathematical Modelling of Weld Phenomena 6 KW - Numerical calculation of temperature load and distortion KW - Circumferential weld seams Y1 - 2002 SN - 978-1-902653-56-3 SP - 685 EP - 702 PB - Maney – IOM CY - London ER - TY - CHAP A1 - Stadtaus, Marc A1 - Michailov, Vesselin A1 - Wohlfahrt, Helmut T1 - Berechnung von Nahtgeometrie, Gefüge, Verzug und Eigenspannungen beim Schmelzschweißen T2 - Schweißen und Schneiden 2001 KW - Berechnung von Nahtgeometrie KW - Gefügesimulation KW - Verzug und Eigenspannungen Y1 - 2001 SN - 978-3-87155-674-6 SP - 315 EP - 321 PB - DVS Verlag CY - Düsseldorf ER - TY - CHAP A1 - Röhrs, K. A1 - Michailov, Vesselin A1 - Wohlfahrt, Helmut T1 - Einfluss von Beimengungen zum Schutzgas beim Lichtbogenschweißen von Aluminiumwerkstoffen T2 - Schweißen und Schneiden 2001 KW - Lichtbogenschweißen von Aluminiumwerkstoffen KW - Einfluss von Beimengungen zum Schutzgas Y1 - 2001 SN - 978-3-87155-674-6 SP - 349 EP - 354 PB - DVS Verlag CY - Düsseldorf ER - TY - GEN A1 - Stadtaus, Marc A1 - Michailov, Vesselin A1 - Wohlfahrt, Helmut T1 - Numerical calculation of the main factors on cold cracking T2 - Materialwissenschaften und Werkstofftechnik KW - cold cracks; finite‐element‐analysis; Kaltrisse Y1 - 2003 U6 - https://doi.org/10.1002/mawe.200390007 SN - 0933-5137 SN - 1521-4052 VL - 34 IS - 1 SP - 145 EP - 151 ER - TY - GEN A1 - Kornienko, Elena A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Corrosion resistance of zinc-coated structured sheet metals T2 - Corrosion Science N2 - The purpose of this study is to characterise the corrosion behaviour of zinc-coated sheet metals after a structuring process using the salt spray test. The investigated structured material is manufactured by hydroforming and has a periodic hexagonal geometry. The corrosion behaviour has been evaluated by estimating the development of the corrosion area and penetration depth. The results of the investigation show that the corrosion area is larger on the smooth sheet than on the structured sheet. The difference between the structured and smooth sheets is negligible with increasing exposure time. Furthermore, the reasons for the different corrosion behaviours are discussed. KW - Corrosion KW - structur sheet metals Y1 - 2013 UR - http://www.sciencedirect.com/science/article/pii/S0010938X12006233 SN - 0010-938X VL - Vol. 69 SP - 270 EP - 280 ER - TY - GEN A1 - Voß, O. A1 - Michailov, Vesselin A1 - Decker, I. T1 - Erweiterung der numerischen Schweißsimulation zur Untersuchung metallkundlicher Fragestellungen T2 - Zeitschrift für Metallkunde KW - numerische Schweißsimulation,Gefügeumwandlungen,Werkstoffkennwerte Y1 - 2001 SN - 0044-3093 VL - 92 IS - 3 SP - 293 EP - 299 ER - TY - GEN A1 - Thomas, Karl A1 - Michailov, Vesselin A1 - Wohlfahrt, Helmut T1 - Zähigkeitsuntersuchungen an schmalen Verfahrenseinflusszonen pressstumpfgeschweißter Stähle T2 - Schweißen und Schneiden KW - Zähigkeitsuntersuchungen KW - Pressstumpschweißung Y1 - 2000 VL - 52 IS - 12 SP - 734 EP - 745 ER - TY - THES A1 - Stadtaus, Marc T1 - FE-Simulation der Verteilung von Wasserstoff und Stickstoff in Schweißverbindungen KW - FE-Simulation, Kaltrisse, Stickstoffverteilung Y1 - 2014 UR - http://www.shaker.de/de/content/catalogue/index.asp?lang=de&ID=8&ISBN=978-3-8440-2537-8 SN - 978-3-8440-2537-8 PB - Shaker Verlag CY - Aachen ER - TY - CHAP A1 - Ossenbrink, Ralf A1 - Genchev, Gancho Vladimirov A1 - Doynov, Nikolay ED - Michailov, Vesselin T1 - Simulation der Schweißeigenspannungen und des -verzuges unter Berücksichtigung der Gefügeumwandlungen mit dem STAAZ-Modell T2 - Internationales Symposium Schweißtechnik - Verfahren, Werkstoffe, Simulation, Cottbus, 6. November 2013 N2 - Die vorliegende Arbeit stellt das von Professor Michailov vorgeschlagene Spitzentemperatur-Austenitisierungs- Abkühlzeit-Modell für die thermomechanische Schweißsimulation unter Berücksichtigung der Gefügeumwandlungen vor. Das Modell erfasst die für die Gefügeausbildung maßgebenden Temperaturzyklen durch seine drei so genannten STAAZ-Parameter: Spitzentemperatur, Austenitisierungs- und Abkühlzeit. Die Korrelation dieser Temperaturzyklusparameter mit den thermomechanischen gefügeabhängigen Werkstoffeigenschaften erfolgt auf Grundlage einer empirischen Datenbasis. Mit der vorgenommenen Erweiterung zu Mehrmalig-(M-)STAAZ lässt sich das aus einem vorgelagerten Temperaturzyklus entstandene Zwischengefüge berücksichtigen. KW - Schweißsimulation; STAAZ-Modell ; thermomechanische Werkstoffkennwerte ; Mehrlagenschweißungen Y1 - 2013 SN - 978-3-8440-2319-0 SP - 149 EP - 167 PB - Shaker Verlag CY - Aachen ER - TY - THES A1 - Kornienko, Elena T1 - Einfluss der Beschichtung und des Schweißens auf das Korrosionsverhalten von strukturierten Blechen KW - Korrosion; Korrosionsschutz; Beschichtung; Schweißen; strukturiertes Blech Y1 - 2014 SN - 978-3-8440-3087-7 PB - Shaker CY - Aachen ER - TY - THES A1 - Sasse, Ina T1 - Schneiden und Schweißen strukturierter Bleche mit Faserlaser KW - Laserstrahlschneiden; Laserstrahlschweißen; Forschung und Entwicklung; Fügetechnik Y1 - 2014 SN - 978-3-8440-3035-8 PB - Shaker CY - Aachen ER - TY - THES A1 - Kapp, Mirjam T1 - Untersuchung der Einflussfaktoren auf die Kaltrissanfälligkeit niedriglegierter Stähle beim Laserstrahlschweißen an zylindrischen Bauteilen KW - Laserstrahlschweißen; Schweißsimulation; Finite-Elemente-Methode; Eigenspannungen; Werkstoffdaten; Kaltrisse Y1 - 2014 SN - 978-3-8440-3452-3 PB - Shaker CY - Aachen ER - TY - THES A1 - Stapelfeld, Christoph T1 - Vereinfachte Modelle zur Schweißverzugsberechnung N2 - Joining by means of welding has a vital importance in many sectors of industry. However, the uneven heating of the welded structure results in unwanted distortions, which has to be removed by cost-intensive after treatments. Knowing the welding distortions in an early stage of the product development cycle enables taking countermeasures or define after treatments, already in the product planning. The aim of this research study is the development and implementation of an analytic numerical hybrid model for the distortion calculation of large welded structures. The basis of the hybrid model is the analytical shrinkage force model, which is upgraded for modern welding processes and new materials. By means of experimental as well as numerical investigations, the instability of thin walled structures during welding is reviewed and a possibility for capturing is proposed. The linking of the analytical and the numerical method opens up the possibility for calculating the distortions caused by curved trajectories. To simplify the application of the hybrid model, a software will be programmed, including the complex mathematical approach of the shrinkage force model. It determines the mechanical loads, depending on the geometry of the welded structure, material data and weld parameters. The verification of the program as well as the coupling procedure is done on butt joints. The same welded structures are used for the investigation of the stability and the sensibility of the hybrid model afterwards. Finally the hybrid model will be applied to welded structures of different complexity and the results will be compared with experimental measurements. At the beginning butt and T-joints are determined, followed by the distortion calculation of a evaluation model made up of 8 welds. At the end an entire section of a ship deck, whereupon different elements are assembled by about 90 welds on a 20x16 meter large ground plate, is estimated. N2 - Dem Fügen mittels Schweißen kommt in vielen Industriezweigen eine zentrale Bedeutung zu. Durch die ungleichmäßige Erwärmung der Schweißverbindung kommt es jedoch zu unerwünschten Verformungen, die durch kostenintensive Nachbehandlungen beseitigt werden müssen. Ist der bleibende Schweißverzug bereits in einem frühen Stadium des Produktentwicklungszyklus bekannt, können geeignete Gegenmaßnahmen ergriffen oder Nachbehandlungen bereits in der Produktplanung festgelegt werden. Das Kernziel dieser Arbeit ist die Entwicklung und Umsetzung eines gekoppelten analytisch numerischen Hybridmodells für die Schweißverzugsberechnung von Großstrukturen. Die Basis hierfür liefert das Schrumpfkraftmodell, welches um moderne Schweißverfahren und neue Werkstoffe erweitert wird. Sowohl experimentell als auch mittels numerischer Analysen wird die Instabilität dünnwandiger Strukturen untersucht und eine mögliche Erfassung im Schrumpfkraftmodell vorgeschlagen. Durch die analytisch numerische Kopplung stellt auch die Berechnung der Verzüge, hervorgerufen durch krummlinig wandernde W\"armequellen keine Hürde mehr dar und wird implementiert. Um die Anwendung des Hybridmodells zu vereinfachen, wird ein Programm entwickelt, welches die umfangreiche mathematische Vorgehensweise des Schrumpfkraftmodells beinhaltet und aufgrund der Geometrie der Schweißverbindung, des Werkstoffs und der Schweißparameter die mechanischen Lasten berechnet. Die Verifizierung der Software, des Kopplungsalgorithmus sowie die Untersuchung der Stabilität und Sensibilität des Hybridmodells erfolgt an Stumpfstoßverbindungen. Abschließend wird das Modell an unterschiedlich komplexen Schweißkonstruktionen angewandt und die berechneten Schweißverzüge mit experimentellen Messungen verglichen. Eingangs werden einfache I- und T-Stoßverbindungen betrachtet. Es folgt die Verzugsberechnung eines Demonstrators aus dem Schiffbau mit 8 Schweißnähten sowie einer gesamten Decksektion mit ca. 90 Nähten, wobei verschiedene Elemente auf eine Grundplatte von 20x16 Metern gefügt werden. KW - Schweißen KW - Schweißverzug KW - Schrumpfkraftmodell KW - Weld Distortion KW - shrinkage force Y1 - 2016 SN - 978-3-8440-4142-2 PB - Shaker Verlag GmbH CY - Aachen ER - TY - GEN A1 - Dreibati, Ossama A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Quantification of cold cracking parameters of high strength steels by physical simulation under welding conditions T2 - Quarterly journal of the Japan Welding Society N2 - Cold cracks in welds are the result of the formation of brittle microstructure as martensite in the presence of diffusible hydrogen as well as of tensile stresses. Cold cracks occur when the combination of cold crack influence parameters (CCIP) overcomes a critical limit. In this study, critical combinations of CCIP were identified with an enhanced test procedure under welding conditions. The test is based on the physical simulation technique of heat affected zone (HAZ) and it is carried out using the test and simulation center Gleeble 3500. Thereby, laboratory special specimens are charged with hydrogen from pure hydrogen atmosphere in the initial stage of the test. Rigidly restraint specimen section is subjected to different weld temperature cycles. Through the thermal exposure, the desired microstructure of HAZ is set in the test zone of the restraint specimen section. A plastic deformation takes place owing to the prevented expansion during heating and contraction of the specimen during cooling. Consequently, compressive or tensile reactions stresses arise in the deformed zone. Cracked specimen represents a critical combination of the CCIP. The quantitative cold crack criterion separates the cold crack susceptible combinations from those non susceptible. KW - Cold Cracking KW - Physical Simulation KW - High Strength Steel Y1 - 2013 U6 - https://doi.org/10.2207/qjjws.31.148s SN - 0288-4771 VL - 31 IS - 4 SP - 148 EP - 152 ER - TY - GEN A1 - Michailov, Vesselin A1 - Dreibati, Ossama A1 - Ossenbrink, Ralf A1 - Schweizer, Frank T1 - Rechnergestützte Vorhersage der Kaltrissneigung laserstrahlgeschweißter Bauteile aus hochfesten Stählen - Teil 1 T2 - Schweißen und Schneiden : Fachzeitschrift für Schweißen und verwandte Verfahren KW - Kaltriss KW - hochfeste Stähle KW - laserstrahlgeschweißte Bauteile Y1 - 2013 SN - 0036-7184 VL - 65 IS - 11 SP - 776 EP - 781 ER - TY - GEN A1 - Zhang, Wei A1 - Melcher, Reinhold A1 - Travitzky, Nahum A1 - Greil, Peter T1 - Three-Dimensional Printing of Complex-Shaped Alumina/Glas Composites T2 - Advanced engineering materials Y1 - 2009 U6 - https://doi.org/10.1002/adem.200900213 SN - 1527-2648 VL - 11 IS - 12 SP - 1039 EP - 1043 ER - TY - CHAP A1 - Cypris, Jochen A1 - Weclas, Miroslaw A1 - Greil, Peter A1 - Schlier, Lorenz M. A1 - Travitzky, Nahum A1 - Zhang, Wei T1 - Application of macro-cellular SiC reactor to diesel engine-like injection and combustion conditions T2 - Porous Media and its Applications in Science, Engineering, and Industry: Fourth International Conference, Potsdam, Germany, 17-22 June 2012 KW - Three-dimensional printing, Macro-cellular SiSiC, complex shaped ceramic composites Y1 - 2012 SN - 978-0-7354-1053-4 U6 - https://doi.org/10.1063/1.4711197 SP - 341 EP - 346 PB - AIP, American Inst. of Physics CY - Melville, NY ER - TY - GEN A1 - Schlier, Lorenz M. A1 - Zhang, Wei A1 - Travitzky, Nahum A1 - Greil, Peter A1 - Cypris, Jochen A1 - Weclas, Miroslaw T1 - Macro-Cellular Silicon carbide Reactors for Nonstationary Combustion Under Piston Engine-Like Conditions T2 - International Journal of Applied Ceramic Technology KW - Three-dimensional printing KW - Macro-cellular SISIC KW - Complex shaped ceramic composites Y1 - 2011 U6 - https://doi.org/10.1111/j.1744-7402.2010.02591.x SN - 1744-7402 VL - 8 IS - 5 SP - 1237 EP - 1245 ER - TY - GEN A1 - Zhang, Wei A1 - Travitzky, Nahum A1 - Hu, Chunfeng A1 - Zhou, Yanchun A1 - Greil, Peter T1 - Reactive Hot Pressing and Properties of Nb2AlC T2 - Journal of the American Ceramic Society KW - MAX phases KW - Ceramic KW - Reactive Hot Pressing Y1 - 2009 U6 - https://doi.org/10.1111/j.1551-2916.2009.03187.x SN - 1551-2916 SN - 0002-7820 VL - 92 IS - 10 SP - 2396 EP - 2399 ER - TY - GEN A1 - Zhang, Wei A1 - Travitzky, Nahum A1 - Greil, Peter T1 - Formation of NbAl3/Al2O3 Composites by pressureless reactive Infiltration T2 - Journal of the American Ceramic Society KW - NbAl3/Al2O3 Composites KW - Pressing and three-dimensional printing KW - Reactive Infiltration Y1 - 2008 U6 - https://doi.org/10.1111/j.1551-2916.2008.02583.x SN - 1551-2916 SN - 0002-7820 VL - 91 IS - 9 SP - 3117 EP - 3120 ER - TY - GEN A1 - Melcher, Reinhold A1 - Zhang, Wei A1 - Travitzky, Nahum A1 - Greil, Peter T1 - 3D-Printing of Al2O3/Cu-O Composites T2 - Ceramic Forum international KW - Al2O3/Cu-O Composites KW - Pressureless Infiltration KW - 3D-Printing Y1 - 2006 SN - 0173-9913 VL - 83 IS - 13 SP - 18 EP - 22 ER - TY - GEN A1 - Genchev, Gancho Vladimirov A1 - Doynov, Nikolay A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Modelling the Local Microstructure Properties due to Multi-Pass Welding T2 - Materials Science Forum Y1 - 2017 U6 - https://doi.org/10.4028/www.scientific.net/MSF.879.595 SN - 0255-5476 SN - 1662-9752 N1 - International Conference on Processing & Manufacturing of Advanced Materials Processing, Fabrication, Properties, Applications, May 29 - June 3, 2016 Graz, Austria VL - Vol. 879 SP - 595 EP - 600 ER - TY - GEN A1 - Michailov, Vesselin A1 - Doynov, Nikolay T1 - Analytical-Numerical Modeling Approach for Calculation of the Structural Distortions after Welding and Thermal Straightening T2 - Journal of Mechanics Engineering and Automation Y1 - 2016 U6 - https://doi.org/10.17265/2159-5275/2016.05.004 SN - 2159-5283 SN - 2159-5275 VL - 6 IS - 5 SP - 246 EP - 253 ER - TY - GEN A1 - Jakobsen, Daniel A1 - Zhang, Wei A1 - Doynov, Nikolay A1 - Böhm, Anna A1 - Malzbender, Jürgen A1 - Michailov, Vesselin A1 - Roosen, Andreas T1 - Thermal shock behaviour of laminated multilayer refractories for steel casting applications reinforced by residual stresses T2 - Ceramics International Y1 - 2016 U6 - https://doi.org/10.1016/j.ceramint.2016.05.149 SN - 0272-8842 VL - 42 IS - 12 SP - 13562 EP - 13571 ER - TY - GEN A1 - Zhang, Wei A1 - Doynov, Nikolay A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Physical and FE-Simulation of Thermal Shock Behaviour of Refractory Ceramics T2 - refractories WORLDFORUM Y1 - 2016 SN - 1868-2405 VL - 8 IS - 2 SP - 110 EP - 117 ER - TY - CHAP A1 - Zhang, Wei A1 - Priefer, Marian A1 - Olenina, Mariia A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Additive manufacturing by laser beam build-up welding T2 - 6th International Conference on Additive Technologies - iCAT 2016, Nürnberg, Germany, 29. - 30. November 2016 Y1 - 2016 SN - 978-961-285-537-6 SP - 324 EP - 327 ER - TY - GEN A1 - Atanga, Valetine Kubong A1 - Zhang, Wei A1 - Dreibati, Ossama A1 - Doynov, Nikolay A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin A1 - Scheffler, Michael T1 - Alumina-mullite Materials for Refractory Applications: Microstructure, Physical and Finite Element Simulation of Thermal Shock Behaviour T2 - refractories WORLDFORUM Y1 - 2012 SN - 1868-2405 VL - 4 IS - 1 SP - 159 EP - 164 ER - TY - GEN A1 - Koltsova, Tatiana S. A1 - Michailov, Vesselin T1 - Hybrid Composite Materials Aluminum-Carbon Nanostructures T2 - Materials science medziagotyra Y1 - 2015 SN - 1392-1320 SN - 2029–7289 VL - 21 IS - 3 SP - 372 EP - 375 ER - TY - GEN A1 - Koltsova, Tatiana S. A1 - Tolochko, Oleg V. A1 - Michailov, Vesselin T1 - Effect of hot pressing modes on the structure and properties of an aluminum-carbon nanofibers’ composite material T2 - Metal Science and Heat Treatment Y1 - 2015 U6 - https://doi.org/10.1007/s11041-015-9793-6 SN - 0026-0673 SN - 1573-897 VL - 56 IS - 9–10 SP - 525 EP - 530 ER - TY - CHAP A1 - Naumov, Anton A1 - Chenikov, Evgenii V. A1 - Golubev, Iurii A1 - Michailov, Vesselin T1 - Numerical simulation and microstructure analysis of friction stir welded Al 6082 T2 - METAL 2015, 24th International Conference on Metallurgy and Materials, conference proceedings, June 3rd-5th 2015, Brno Y1 - 2015 SN - 978-80-87294-62-8 PB - Tanger CY - Ostrava ER - TY - GEN A1 - Michailov, Vesselin T1 - Prediction of the Properties of Heat-Affected Zone of Welded Joints of Sheets from Aluminum Alloys with Structured Surface T2 - Metal Science and Heat Treatment Y1 - 2016 SN - 0026-0673 SN - 1573-8973 VL - 58 IS - 1-2 SP - 46 EP - 50 ER - TY - GEN A1 - Karkhin, Victor A. A1 - Garkov, Sergey Vladimirovich A1 - Michailov, Vesselin T1 - Calculation of thermal processes in welding thick plates with moving axisymmetric heat sources T2 - Welding International Y1 - 2016 SN - 0950-7116 SN - 1754-2138 VL - 30 IS - 9 SP - 708 EP - 711 ER - TY - CHAP A1 - Ivanov, Sergey Y. A1 - Panchenko, Oleg V. A1 - Karkhin, Victor A. A1 - Michailov, Vesselin A1 - Velichko, Olga V. T1 - Comparative study of mechanical inhomogeneity of laser and friction stir welded joints of Al-Mg-Si alloy T2 - METAL 2015, 24th International Conference on Metallurgy and Materials, conference proceedings, June 3rd-5th 2015, Brno Y1 - 2016 SN - 978-80-87294-62-8 PB - Tanger CY - Ostrava ER - TY - GEN A1 - Schleuß, Leander A1 - Richter, Thomas A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Plasma Cutting of Structured Sheet Metals in Comparison with Laser Beam Cutting T2 - Journal of Materials Science and Engineering Y1 - 2015 U6 - https://doi.org/10.17265/2161-6221/2015.3-4.004 SN - 2161-6221 VL - 5 IS - 3-4 SP - 135 EP - 144 ER - TY - CHAP A1 - Petrov, Peter A1 - Bokuchava, Gizo A1 - Papushkin, Igor A1 - Genchev, Gancho Vladimirov A1 - Doynov, Nikolay A1 - Michailov, Vesselin A1 - Ormanova, Maria T1 - Neutron diffraction studies of laser welding residual stresses T2 - 19th International Conference and School on Quantum Electronics: Laser Physics and Applications, 26–30 September 2016 Sozopol, Bulgaria Y1 - 2017 UR - http://proceedings.spiedigitallibrary.org/proceeding.aspx?articleid=2597355 SN - 978-1-5106-0953-2 SN - 978-1-5106-0954-9 U6 - https://doi.org/10.1117/12.2261802 PB - SPIE CY - Bellingham, Wash. ER - TY - GEN A1 - Nikitin, Alexander A1 - Schleuß, Leander A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Corrosion Behavior of Brazed Zinc-Coated Structured Sheet Metal T2 - International Journal of Corrosion Y1 - 2017 U6 - https://doi.org/10.1155/2017/4768505 SN - 1687-9333 SN - 1687-9325 VL - 2017 SP - 4768505 ER - TY - CHAP A1 - Tolochko, Oleg V. A1 - Michailov, Vesselin A1 - Rudskoy, Andrey I. ED - Devezas, Tessaleno ED - Leitão, João ED - Sarygulov, Askar T1 - Metal Matrix/Nanocarbons Composites Based on Copper and Aluminum T2 - Industry 4.0 : Entrepreneurship and Structural Change in the New Digital Landscape Y1 - 2017 SN - 978-3-319-49604-7 SN - 978-3-319-49603-0 SP - 205 EP - 217 PB - Springer International Publishing CY - Cham ER - TY - GEN A1 - Ivanov, Sergey Y. A1 - Karkhin, Victor A. A1 - Michailov, Vesselin T1 - Optimization of welding conditions for curvilinear T2 - Welding International KW - Arc welding KW - optimization KW - structured panel KW - curvilinear seam KW - sources method KW - fastest descent method Y1 - 2017 U6 - https://doi.org/10.1080/09507116.2017.1353276 SN - 0950-7116 VL - 31 IS - 12 SP - 929 EP - 933 ER - TY - GEN A1 - Doynov, Nikolay A1 - Michailov, Vesselin T1 - Distortion analysis of heat spot straightening thin-walled welded structures: part 1: analytical-numerical approach T2 - The International Journal of Advanced Manufacturing Technology N2 - The work deals with the elastic-plastic thermo-mechanical deformation process after spot heating of large thin plates. It promotes a new theoretical model of the process. The main target is to clarify the kinetics of the plastic strain formation during thermal straightening and to explore the main interactions. For this purpose, a simplified mechanical problem is formulated and applied. As a result, definite thermo-mechanical relations between temperature, initial strain, and accumulated plastic strain are obtained. Finally, a verification study is presented and discussed. The results contribute to extending the knowledge about the process and to establishing a theoretical background for development of applied analytical or analytical-numerical approaches for practical use in the designing and planning phases in welding production. An application to a particular case is described in an accompanying paper (part 2). KW - Straightening KW - Elastic-plastic analysis KW - Distortion analysis KW - Computational welding mechanics KW - Virtual manufacturing Y1 - 2018 UR - https://link.springer.com/article/10.1007%2Fs00170-017-0911-z U6 - https://doi.org/10.1007/s00170-017-0911-z SN - 0268-3768 SN - 1433-3015 VL - 94 IS - 1-4 SP - 667 EP - 676 ER - TY - GEN A1 - Evdokimov, Anton A1 - Springer, Katrin A1 - Doynov, Nikolay A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Heat source model for laser beam welding of steel-aluminum lap joints T2 - International Journal of Advanced Manufacturing Technology N2 - In this study, a three-dimensional thermal conduction model based on the finite element analysis was established to predict a heat distribution during laser welding in overlap configuration of austenitic stainless steel 1.4301 and hardenable aluminum alloy 6016. A hybrid model based on two expanded curve-rotated volumetric heat sources is suggested to capture the complex weld geometry. Since thermal flow in the overlap area is a crucial part of the model, an analytic calculation of a thermal contact conductance between the plates and its subsequent implementation in the FE model through a superposition of two contact surfaces are described in details in this paper. Full thermal cycles, weld shapes, and thus mixing grades were successfully predicted by means of the developed model for different parameter combinations. KW - Laser welding Dissimilar joint Heat source model Finite element analysis Thermal simulation Weld shape KW - Dissimilar joint KW - Heat source model KW - Finite element analysis KW - Thermal simulation KW - Weld shape Y1 - 2017 UR - https://link.springer.com/article/10.1007/s00170-017-0569-6 U6 - https://doi.org/10.1007/s00170-017-0569-6 SN - 0268-3768 SN - 1433-3015 VL - 93 IS - 1-4 SP - 709 EP - 716 ER - TY - GEN A1 - Shapovalov, Oleg A1 - Hantelmann, Cord A1 - Michailov, Vesselin A1 - Kodgaspirov, G. E. T1 - Influence of welding method on fatigue strength and destruction character of aluminum foam sandwiches T2 - Deformatsiya i Razrushenie materialov N2 - An influence of the arc welding and the laser welding on fatigue properties and destruction mechanisms of aluminum foam sandwich has been studied. It was found that specimens made by the arc welding had the best fatigue strength. Comparative results of four point bending fatigue tests of the non-welded specimens such as butt welded joints made by different welding methods are presented. KW - aluminum foam KW - metallic foam sandwich KW - fatigue strength KW - four-point bending KW - butt welded joint Y1 - 2017 UR - http://www.nait.ru/journals/number.php?p_number_id=2612 SN - 1814-4632 IS - 5 ER - TY - PAT A1 - Michailov, Vesselin A1 - Ossenbrink, Ralf A1 - Schleuß, Leander A1 - Springer, Katrin A1 - Zoeke, Jörg T1 - Strukturierte Tailored Blanks T1 - Structured tailored blank useful as a semi-finished product or a finished product, which is used as a component, preferably wall element, floor element, ceiling element and/or element of chassis of vehicle, comprises at least two sheets N2 - Die Erfindung betrifft ein strukturiertes Tailored Blank, umfassend mindestens zwei Fügepartner, wobei mindestens ein Fügepartner ein strukturierter Fügepartner ist und wobei der strukturierte Fügepartner regelmäßig angeordnete Versteifungselemente umfasst und wobei der strukturierte Fügepartner an mindestens einen weiteren Fügepartner gefügt ist. N2 - Structured tailored blank comprises at least two sheets. At least one sheet is at least one structured sheet. The structured sheet comprises regularly arranged stiffening elements of honeycomb shapes without planar sections. The stiffening elements are separated by bars. The structured sheet is joined to at least one additional sheet, and both the sheets are not similar. An independent claim is also included for producing the structured tailored blank, comprising the providing first structured sheet, providing at least one additional sheet, which is not similar to the first sheet, and joining the first sheet with at least one additional sheet. Y1 - 2014 UR - https://depatisnet.dpma.de/DepatisNet/depatisnet?action=pdf&docid=DE102013101171A1 ER - TY - GEN A1 - Koltsova, Tatiana S. A1 - Shakov, Fedor M. A1 - Voznyakovskiy, A. A. A1 - Lyashkov, A. I. A1 - Tolochko, Oleg V. A1 - Rudskoy, Andrey I. A1 - Nasibulin, Albert G. A1 - Michailov, Vesselin T1 - Fabrication of a Compacted Aluminum-Carbon Nanofiber Material by Hot Pressin T2 - Technical Physics Y1 - 2014 U6 - https://doi.org/10.1134/S1063784214110139 SN - 1063-7842 VL - 59 IS - 11 SP - 1626 EP - 1630 ER - TY - CHAP A1 - Krawczynski, Damian A1 - Doynov, Nikolay A1 - Michailov, Vesselin T1 - Minimization of Residual Welding Stress and Distortins in Aluminium-Steel Hybrid Structure T2 - Innowacje w procesach produkcyjnych, technologicznych i bezpieczeństwie : XXXVIII Studencka Sesja Naukowa, Częstochowa, 29 maj 2014 : praca zbiorowa Y1 - 2014 SN - 879-83-63989-02-6 SP - 59 EP - 63 PB - Wydawnictwo Wydziału Inżynierii Produkcji i Technologii Materiałów Politechniki Częstochowskie CY - Częstochowa ER - TY - GEN A1 - Bobrynina, Elizaveta A1 - Alkhalaf, Ahmad A. A1 - Shamshurin, Aleksey A1 - Tolochko, Oleg V. A1 - Michailov, Vesselin T1 - Synthesis of Fe-ZrO2 composite powders by thermochemical method T2 - Key Engineering Materials Y1 - 2017 U6 - https://doi.org/10.4028/www.scientific.net/KEM.721.285 SN - 1662-9795 VL - 721 SP - 285 EP - 289 ER - TY - GEN A1 - Hartel, Udo A1 - Ilin, Alexander A1 - Sonntag, Steffen A1 - Michailov, Vesselin T1 - Nonlinear optimization methods for the determination of heat source model parameters T2 - Materials Science Forum Y1 - 2017 U6 - https://doi.org/10.4028/www.scientific.net/MSF.879.2008 SN - 1662-9752 SN - 0255-5476 VL - 879 SP - 2008 EP - 2013 ER - TY - GEN A1 - Hartel, Udo A1 - Ilin, Alexander A1 - Michailov, Vesselin A1 - Gibmeier, Jens A1 - Bantel, Christoph T1 - Finite Element Modelling for the Structural Analysis of Al-Cu Laser Beam Welding T2 - Physics Procedia Y1 - 2016 U6 - https://doi.org/10.1016/j.phpro.2016.08.147 SN - 1875-3892 VL - 83 SP - 1404 EP - 1414 ER - TY - GEN A1 - Genchev, Gancho Vladimirov A1 - Doynov, Nikolay A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin A1 - Bokuchava, Gizo A1 - Petrov, Peter T1 - Residual stresses formation in multi-pass weldment: A numerical and experimental study T2 - Journal of Constructional Steel Research N2 - In this study, the residual stresses distribution induced by multi-pass arc welding of the steel S355J2+N are investigated experimentally and numerically. An extended approach is used for the simulations, which considers the change of the local microstructure properties due to multiple reheating. Experimental material data obtained from physical welding simulations with Gleeble® are used for the model calibration. The experimental stress study is performed using a neutron diffraction method on a fourier stress diffractometer. Numerical analysis of the welding stresses formation in the weldment is performed and compared to the experimental study. The results explain the influence of the welding thermal history on the resulting local thermo-mechanical properties in the heat-affected zone and, thus, on the residual stress distribution. The consideration of the local microstructure properties in the welding simulation leads to a significant increase in accuracy of the numerical results. The major influence factor on the residual stress formation is the change in the interpass microstructure yield strength. When a root pass with short cooling times is subjected to re-austenitisation in the fine-grained zone, the yield strength increases in this area and affects consequently the residual stress distribution. The influence of the reheating is detectable in the depth of the weldment, but it is less significant for the residual stress formation near the surface of the welded joint. KW - Multi-pass weldment KW - Steel S355 KW - Thermo-mechanical properties KW - Stress distribution KW - Welding simulation KW - Neutron diffraction Y1 - 2017 UR - http://www.sciencedirect.com/science/article/pii/S0143974X17303358 U6 - https://doi.org/10.1016/j.jcsr.2017.08.017 SN - 0143-974X VL - 138 SP - 633 EP - 641 ER - TY - GEN A1 - Doynov, Nikolay A1 - Michailov, Vesselin T1 - Distortion analysis of heat spot straightening thin-walled welded structures: part 2: analytical-numerical approach T2 - International Journal of Advanced Manufacturing Technology N2 - An analytical model based on a theoretical model established in the previous work (part 1) is developed. The analytical model considers the particular case of an instantaneous high-density heat source acting on a thin pre-stressed plate. It calculates the plastic strain and the area of the zone of plastic deformation. A theoretical study is performed in order to quantify the major factors that influence the plastic strain formation. Furthermore, the work presents a calculation procedure for distortion analysis of lar ge and complex structures, intended to be used for solving industrial tasks. The calculation procedure consists of a combination of the analytical solution and an elastic finite element analysis with the aid of the inherent strain approach. Various aspects of its application are also discussed. The calculation procedure is finally explained using a simple example. Its reliability and practicability are demonstrated through verification and validation studies. The work is dedicated to the thermal straightening of thin-walled welded structures; however, it can also be related to other processes. KW - Thermal straightening KW - Distortion analysis KW - Computational welding mechanics KW - Finite element analysis KW - Inherent strain method KW - Virtual manufacturing Y1 - 2018 UR - https://link.springer.com/article/10.1007%2Fs00170-017-1214-0 U6 - https://doi.org/10.1007/s00170-017-1214-0 SN - 0268-3768 SN - 1433-3015 VL - 95 IS - 1-4 SP - 469 EP - 478 ER - TY - GEN A1 - Kondratyev, Alex A1 - Morozova, Iuliia A1 - Golubev, Iurii A1 - Hantelmann, Cord A1 - Naumov, Alexander A1 - Michailov, Vesselin T1 - Микроструктура и механические свойства швов после различных режимов импульсной сварки Al – Mg – Si сплавов трением с перемешиванием T1 - Untersuchung von Mikrostruktur und mechanischen Eigenschaften der Al-Mg-Si Legierungen beim Impuls-Rührreibschweißen mit unterschiedlichen Schweißparametern T2 - Metallovedenie i termicheskaya obrabotka metallov N2 - Welded joints of aluminum alloy 6082-T6 formed by the method of pulse friction stir welding are studied. The effect of the power and frequency of the pulses on the microstructure and mechanical properties of the welded joints is determined. Application of an additional pulse during the welding affects the surface quality and the shape of the weld, the distribution of the oxide layer and of particles of the hardening phase, and the grain size in the zone of dynamic recrystallization. KW - pulse friction stir welding KW - power and frequency of pulses KW - microstructure KW - mechanical properties KW - Al – Mg – Si alloy Y1 - 2017 SN - 0026-0819 IS - 11 SP - 25 EP - 30 ER - TY - GEN A1 - Kondrat’ev, Sergey A1 - Morozova, Iuliia A1 - Golubev, Iurii A1 - Hantelmann, Cord A1 - Naumov, Alexander A1 - Michailov, Vesselin T1 - Microstructure and Mechanical Properties of Welds of Al – Mg – Si Alloys After Different Modes of Impulse Friction Stir Welding T2 - Metal Science and Heat Treatment N2 - Welded joints of aluminum alloy 6082-T6 formed by the method of impulse friction stir welding are studied. The effect of the power and frequency of the pulses on the microstructure and mechanical properties of the welded joints is determined. Application of an additional pulse during the welding affects the surface quality and the shape of the weld, the distribution of the oxide layer and of particles of the hardening phase, and the grain size in the zone of dynamic recrystallization. KW - impulse friction stir welding KW - power and frequency of pulses KW - microstructure KW - mechanical properties KW - Al – Mg – Si alloy Y1 - 2018 UR - https://link.springer.com/article/10.1007%2Fs11041-018-0213-6 U6 - https://doi.org/10.1007/s11041-018-0213-6 SN - 0026-0673 VL - 59 IS - 11-12 SP - 697 EP - 702 ER - TY - GEN A1 - Wasilewski, Eric A1 - Wolf, Matthias A1 - Zhang, Wei A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Cu/LaCrO₃ joining by local melt infiltration through laser cladding T2 - Journal of the American Ceramic Society N2 - Direct bonding of copper and porous LaCrO₃ without an extra filler interlayer was successfully completed using local and fast Cu‐infiltration through laser cladding. This significantly reduced the susceptibility of the ceramic to cracking. A high‐speed camera investigation into the wetting and infiltration behavior of a Cu‐melt into LaCrO₃ with a porosity of ~63 vol% was performed. By adjusting the focal distance with a constant laser power of 300 W, the Cu‐melt was rapidly infiltrated into the ceramic preform in 10 seconds. This was completed under atmospheric air conditions, without added inert gas. The joining process developed can be used to fabricate ceramic/metal joints with targeted (micro‐) structure properties by adjusting the infiltrated melt and the infiltration depth, which would be suitable for many applications, such as multifunctional devices, solid oxide fuel cells or heating elements. Y1 - 2018 U6 - https://doi.org/10.1111/jace.15767 SN - 1551-2916 SN - 0002-7820 VL - 101 IS - 10 SP - 4472 EP - 4472 ER - TY - GEN A1 - Michailov, Vesselin A1 - Fritzsche, Sebastian A1 - Hantelmann, Cord A1 - Ossenbrink, Ralf T1 - Aluminium foam sandwiches for lightweight structures T2 - Metal Science and Heat Treatment N2 - The properties of sandwiches with aluminum foam and the special features of their use in lightweight welded structures are determined. The weldability of such sandwiches in foamed and non-foamed conditions is analyzed under friction stir welding, laser beam welding and short arc welding in protective gas. The process and mechanical properties of the welds are studied. The results are generalized in a catalog that may be useful for materials scientists and designers. KW - aluminum KW - aluminum foam KW - welded structures KW - composite materials KW - structure KW - mechanical properties Y1 - 2018 U6 - https://doi.org/10.1007/s11041-018-0238-x SN - 1573-8973 VL - 60 IS - 1-2 SP - 44 EP - 49 ER - TY - GEN A1 - Ivanov, Sergey Y. A1 - Panchenko, Oleg V. A1 - Michailov, Vesselin T1 - Comparative analysis of non-uniformity of mechanical properties of welded joints of Al - Mg - Si alloys in friction stir welding and laser welding T2 - Metal Science and Heat Treatment N2 - The properties of the welded joints of 6082-T6 alloy produced by friction stir welding (FSW) and laser welding(LW) were studied. The maximum temperature and microhardness fields in the friction stir-welded joints were shown to be asymmetrical. The concentrated energy input during laser welding yields a narrow heat-affected zone (HAZ) with sharp changes in mechanical properties. The strength of the FSW joint constitutes 72% and that of the LWjoint—67% of the base metal strength. In case of LW, the minimum hardness of the joint corresponds to the metal of the welded joint, while in case of FSW, it corresponds to the heat-affected zone. At the same maximum heating temperature, the hardness of the heat-affected zone of the friction stir-welded joint is lower compared to laser welding due to substantially lower rates of heating and cooling. KW - friction stir welding KW - laser welding KW - Al – Mg – Si alloy KW - temperature field KW - welded joint KW - microstructure KW - mechanical properties KW - non-uniformity Y1 - 2018 UR - https://link.springer.com/article/10.1007/s11041-018-0289-z U6 - https://doi.org/10.1007/s11041-018-0289-z SN - 0026-0673 VL - 60 SP - 393 EP - 398 ER - TY - GEN A1 - Bonnel, Jean-Marie A1 - Maurer, Michael A1 - Rosert, Reinhard T1 - Submerged-arc surfacing of higt-alloy steels by flux-cored wires T2 - Avtomatičeskaja svarka = Automatic welding N2 - Cored wires are used in numerous welding processes with or without extern al gas or flux shielding. Submerged are welding (SAW) with eored wires, seamed or seamless, for joining mild and low alloyed steel grades is a technique that has demonstrated clear advantages during the three last decades. Ever since its invention, the SAW process has evolved with one main goal: to combine quality with produetivity. With low alloy wires, the benefits have already been clearly demonstrated and widely exploited. However, little has been written on SA Wand cladding with eored wires for eorrosion or he at resisting applieations. Its extension to high alloy eompositions brings eorresponding benefits and adds so me specific and unique features. This paper foeuses on consumable specificities and on the quality and productivity features of SAW with CRA (corrosion resistant alloy) cored wires. It deseribes the potential as weIl as the limitations ofthis technique. Cored wires are now used for submerged are welding of almost aIl stainless steels ranging from soft martensitic to super-duplex, and for aseries of nickel base compositions as weIl as for cladding cobalt base aIloys. Examples of industrial applications with austenitic, duplex, martensitic and heat resisting stainless steels are given to illustrate the potential ofthe eored wire solution. KW - Submerged are welding KW - surfacing KW - cored wire KW - high-alloy steels Y1 - 2019 U6 - https://doi.org/10.15407/as2019.06.01 SN - 0005-111X IS - 6 SP - 4 EP - 13 ER - TY - GEN A1 - Doynov, Nikolay A1 - Stapelfeld, Christoph A1 - Michailov, Vesselin A1 - Pasternak, Hartmut A1 - Launert, Benjamin ED - Sommitsch, Christof ED - Enzinger, Norbert ED - Mayr, Peter T1 - Distortion analysis of large scaled welded structures T2 - Mathematical Modelling of Weld Phenomena 12 : selected peer reviewed papers from the 12th International Seminar Numerical Analysis of Weldability : September 23-26, 2018, Graz, Schloss Seggau - Austria N2 - The work presents an innovative approach for simulation of welding induced distortions, which allows taking into consideration the local effects of the welding process as well as the global interactions in the structure. The approach bases on an integration of analytical and numerical calculation’s procedures in a hybrid model, realized with the aid of the inherent strain concept. The analytical procedure calculates the shrinkage strain components and area of the plastic deformed zone, caused by welding. The calculated strains are then transferred to the global finite element model in order to predict the distortions and stresses in the structure after every welding stage, as well as their final state. The consideration of welding scenarios, weld sequence, clamping conditions and the assembling stages is done by taking into account the intermediate variation of the strain state during the manufacturing steps. The article gives the theoretical basis of the analytical model. The consideration of the essential physical relations is put into discussion. The application of the model is illustrated on complex structures. Its reliability and practicability are demonstrated by means of a validation study. Y1 - 2019 SN - 978-3-85125-615-4 U6 - https://doi.org/10.3217/978-3-85125-615-4 SP - 254 EP - 280 PB - Verlag der Technischen Universität Graz CY - Graz ER - TY - GEN A1 - Naumov, Anton A1 - Isupov, Fedor A1 - Golubev, Iurii A1 - Morozova, Iuliia A1 - Spree, Cornelius T1 - Development of Methodology to Determine the Temperature Influence on Microstructure Evolution during Friction Stir Welding T2 - Papers from Materials Science and Technology 2018 (MS&T18), October 14–18, 2018, Greater Columbus Convention Center, Columbus, Ohio, USA Y1 - 2018 UR - https://www.researchgate.net/publication/328772948_DEVELOPMENT_OF_METHODOLOGY_TO_DETERMINE_THE_TEMPERATURE_INFLUENCE_ON_MICROSTRUCTURE_EVOLUTION_DURING_FRICTION_STIR_WELDING U6 - https://doi.org/10.7449/2018mst/2018/mst_2018_795_802 ER - TY - GEN A1 - Evdokimov, Anton A1 - Ossenbrink, Ralf A1 - Doynov, Nikolay A1 - Michailov, Vesselin ED - Sommitsch, Christof ED - Enzinger, Norbert ED - Mayr, Peter T1 - Laser beam welding of steel-aluminum joints - influence of weld metal elastic-plastic properties on the distortions T2 - Mathematical Modelling of Weld Phenomena 12 : selected peer reviewed papers from the 12th International Seminar Numerical Analysis of Weldability : September 23-26, 2018, Graz, Schloss Seggau - Austria N2 - Great attention is focused nowadays on laser welding of dissimilar steel-aluminum joints in overlap configuration in key-hole mode. It was found that elastic-plastic properties of the weld metal exhibit strong difference to those of the base alloys and can be defined as a function of aluminum content in the weld metal. A developed Finite-Element simulation model allows prediction of the aluminum content as a function of welding parameters and subsequently the elastic-plastic properties of the weld metal as a function of the determined content. The main goal of the present study is to show the impact of the weld metal properties on welding distortions and residual stresses. For that purpose, a sensitivity analysis of the thermomechanical model was performed, where the distortions and residual stresses were computed as a function of welding parameters and therefore as a function of corresponding weld metal properties. The analysis showed that the influence of the weld metal is essential, and its properties should be taken into consideration in the models for better prediction accuracy. Y1 - 2019 SN - 978-3-85125-615-4 U6 - https://doi.org/10.3217/978-3-85125-615-4 SP - 431 EP - 440 PB - Verlag der Technischen Universität Graz CY - Graz ER - TY - GEN A1 - Kaisheva, Darina A1 - Bokuchava, Gizo A1 - Papushkin, Igor A1 - Genchev, Gancho Vladimirov A1 - Doynov, Nikolay A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin A1 - Petrov, Peter T1 - Determination of residual stresses in fiber laser welded stainless steel joints by neutron diffraction method T2 - Proc. SPIE 11047, 20th International Conference and School on Quantum Electronics: Laser Physics and Applications N2 - This study presents an experimental results of residual stress states in stainless steel plate samples with size 100 x 50 x 10 mm welded using a high-power fiber laser. The technological parameters of the welding process were: laser power Q = 15 kW; laser spot size = 0.65 mm; welding speed V = 3 m/min; 4 m/min; 5 m/min, using 30 L/min of protective Ar gas. The neutron diffraction method was used to determine the residual stresses in the bulk of the material. The neutron experiments were performed on the FSD diffractometer at the IBR-2 pulsed reactor in the Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research - Dubna, Russian Federation. The measured residual stress distributions exhibit maxima at weld seam centers. As expected, for all specimens the residual stress is falling down in regions distant from the weld zone. Maximal residual stress value of 492 MPa was observed for sample welded with speed of V = 5 m/min. KW - Diffraction KW - Laser welding KW - Metals KW - Fiber laser KW - Laser processing KW - Laser applications KW - Sensors Y1 - 2019 U6 - https://doi.org/10.1117/12.2516421 CY - Nessebar ER - TY - GEN A1 - Morozova, Iuliia A1 - Obrosov, Aleksei A1 - Naumov, Anton A1 - Królicka, Aleksandra A1 - Golubev, Iurii A1 - Bokov, Dmitry O. A1 - Doynov, Nikolay A1 - Weiß, Sabine A1 - Michailov, Vesselin T1 - Impact of Impulses on Microstructural Evolution and Mechanical Performance of Al-Mg-Si Alloy Joined by Impulse Friction Stir Welding T2 - Materials N2 - Impulse Friction Stir Welding (IFSW) was utilized to join 6082–T6 alloy plates at various impulse frequencies. A distinctive feature of IFSW is the generation of mechanical impulses that enhances the forging action of the tool, and thereby, alters the weld microstructure. The microstructural evolution in the Stir Zone (SZ) with special focus on the strengthening precipitation behavior, and overall mechanical properties of the IFSW joints have been investigated. It was demonstrated that the strengthening β″ precipitates reprecipitated in the SZ of the IFSW joints during natural aging. In contrast, no precipitates were found in the SZ of the Friction Stir Welding (FSW) weld. Partial reversion of β″ after IFSW is supposed to occur due to more developed subgrain network and higher dislocation density introduced by impulses that accelerated precipitation kinetics. Dynamic recrystallisation was facilitated by impulses resulting in a fine, homogeneous structure. There was no significant difference between the microhardness in the SZ, tensile and yield strength of the FSW and IFSW joints. However, the application of impulses demonstrated the smoothing of the hardness reduction in the transition region at the advancing side. The shift of the fracture location from the Heat-Affected Zone (HAZ) by FSW to the SZ as well as higher elongation of the joints by IFSW of lower frequencies could be related to the grain refinement and the change of the grain orientation. KW - Al-Mg-Si alloy KW - impulse friction stir welding (IFSW) KW - precipitation KW - microstructure evolution KW - mechanical properties Y1 - 2021 UR - https://www.mdpi.com/1996-1944/14/2/347/htm U6 - https://doi.org/https://doi.org/10.3390/ma14020347 SN - 1996-1944 VL - 14 IS - 2 ER - TY - GEN A1 - Shapovalov, Oleg A1 - Shapovalova, Mariia A1 - Ossenbrink, Ralf A1 - Heckel, Thomas A1 - Michailov, Vesselin A1 - Weiß, Sabine A1 - Gaal, Mate T1 - Verbessern der Korrosionsbeständigkeit eines hochtemperaturbeständigen Ultraschalldämpfungskörpers mittels Laserstrahl-Auftragschweißen T2 - DVS Berichte 2021 N2 - Während in einem konventionellen Ultraschallprüfkopf ein Kunststoffdämpfungskörper mit Kleber oder Öl an einen Piezoschwinger angekoppelt ist, werden als Hochtemperaturlösung feinporöse sintermetallische Dämpfungsmaterialien mit einer Flüssigglasankopplung eingesetzt. Um dabei das Sintermetall vor dem korrosiven Angriff der Glasschmelze zu schützten, wird am Dämpfungskörper gegenwärtig Gold- oder Platinfolie zeit- und kostenaufwendig appliziert. In der aktuellen Arbeit wurde eine Methode zum Korrosionsschutz der sintermetallischen Oberfläche aus rostfreiem Stahl mittels Laser-Pulverauftragschweißen entwickelt. Im Laufe einer Schweißparameterstudie auf dem Substratmaterial aus massivem rostfreiem Stahl wurde die Eignung unterschiedlicher Auftragsmaterialien auf Nickel- und Kobaltbasis untersucht. Dabei wurde zunächst der Einfluss verschiedener Schweißparameter wie Laserleistung, Vorschubgeschwindigkeit und Pulvermenge auf die Auftragsqualität (Nahtform, Vermischungsgrad, Porosität) metallografisch bewertet. Anschließend wurden die aufgetragenen Schichten hinsichtlich ihrer Korrosionsbeständigkeit getestet. Der Kontakt mit einer flüssigen Glasmischung bei 500 °C hat bei keiner der beschichteten Proben sichtbare Korrosionswirkung gezeigt. Als Resultat der Schweißparameterstudie haben sich besonders die nickelbasierten Pulver als gut geeignete Materialien für den Prozess gezeigt. Die identifizierten Schweißparameter wurden im nächsten Schritt erfolgreich an das sintermetallische Substrat angepasst. Y1 - 2021 UR - https://www.dvs-ev.de/call4papers/abstract.cfm?vid=109&pid=7032 SN - 978-3-96144-147-1 SP - 370 EP - 377 PB - DVS Media GmbH CY - Düsseldorf ER - TY - GEN A1 - Jokisch, Torsten A1 - Doynov, Nikolay A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Heat source model for electron beam welding of nickel-based superalloys T2 - Materials testing : Materialprüfung Y1 - 2021 U6 - https://doi.org/10.1515/mt-2020-0002 SN - 2195-8572 SN - 0025-5300 VL - 63 IS - 1 SP - 17 EP - 28 ER - TY - GEN A1 - Valkov, Stefan A1 - Kotlarski, Georgi A1 - Ormanova, Maria A1 - Doynov, Nikolay A1 - Ossenbrink, Ralf A1 - Petrov, Peter A1 - Michailov, Vesselin T1 - Crystallography and Mechanical Properties of Wire Arc Additively Manufactured Al5356 Components T2 - Comptes Rendus de L'Academie Bulgare des Sciences N2 - In this study, we present results of the evolution of the crystallographic texture and imperfections, as well as the corresponding mechanical properties of wire and arc additively manufactured (WAAM) Al5356 specimens, studied by X-ray diffraction (XRD) and tensile testing, respectively. The results show that the phase composition is in the form of a face-centred cubic (fcc) crystal structure, corresponding to the base material, as well as some traces of oxide phase Al2O3. The WAAM specimen growing is accompanied by a slight change in the preferred crystallographic orientation, from (111) to (200) and a decrease in the imperfections concentration. Also, it was found that the ultimate tensile strength (UTS), yield strength (YS), and elongation slightly decrease from the initial to the more advanced stages of growth. KW - wire arc additive manufacturing KW - Al5356 alloy KW - crystallography KW - mechanical properties Y1 - 2021 U6 - https://doi.org/10.7546/CRABS.2021.06.03 SN - 1310-1331 VL - 74 IS - No. 6 SP - 820 EP - 827 ER - TY - GEN A1 - Jokisch, Torsten A1 - Doynov, Nikolay A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin A1 - Böttger, Bernd A1 - Senger, Aleksej T1 - Analysis of temperature field during electron beam welding of hot crack sensitive nickel base alloy T2 - IEBW International Electron Beam Welding Conference: lectures of the 6th International Conference taking place online on 9 to 10 March 2021 N2 - The use of temperature-resistant nickel-based superalloys in the field of industrial gas turbines is increasing due to constantly rising operating temperatures. Among different joining methods the electron beam welding is commonly used for manufacturing of turbine components because it provides a reduced heat input. However, the highly localized beam impact causes high temperature gradients and leads to the formation of hot cracks. Welding of such material with a high brittle temperature range is challenging and needs an increasing effort of process adaption. Experiments indicate a significant improvement of hot crack susceptibility when welding outside the common welding parameter range. To understand these observations a study of the temperature field in the specimens using numerical simulations was carried out. For this purpose, a validated simulation model was used. Special attention was paid to the domain in close vicinity of the weld pool. The results illustrate the velocity of solidification isotherm as well as the temperature rates when crossing the melting point. Finally, the relations between thermal fields, crack types and distributions in the different specimens are discussed. Y1 - 2021 UR - https://www.dvs-media.eu/media/pdf/DVS_Bericht_368_Inhalt.pdf SN - 978-3-96144-133-4 SP - 81 EP - 87 PB - DVS Media GmbH CY - Düsseldorf ER - TY - GEN A1 - Ermilova, Evgeniia A1 - Nikitin, Alexander A1 - Weiß, Sabine ED - Daehn, Glenn ED - Cao, Jian ED - Kinsey, Brad ED - Tekkaya, A. Erman ED - Vivek, Anupam ED - Yoshida, Yoshinori T1 - The Local Strain Evolution for Structured Sheet Metals During Uniaxial Deformation T2 - Forming the Future : Proceedings of the 13th International Conference on the Technology of Plasticity N2 - Structured materials can be progressive alternatives to commonly used flat sheets because of their higher bending stiffness and stability compared to flat sheet metals, made of the same alloy. The application of sheet metals requires accurate information regarding their strength and deformation behavior. Such data are not commonly available and have to be measured by specific test setups and implementation of tests. The aim of this work is to obtain new knowledge about deformation mechanisms of structured sheet metals. Structured sheet metals (SSM) made of conventional deep-drawing steel DC04 were investigated by means of tensile tests. The influence of the structure type arrangement on the deformation behavior was analyzed. The evolution of local strains was analyzed by means of strain gauge measurements as well as 3D-displacement measurements with an ARAMIS highresolution camera system. Local orientation changes in different structural elements were measured using the electron backscatter diffraction technique. KW - structured sheet metals, ssm, tensile test, ARAMIS, strain gauge, EBSD, REM, electron microscopy, DC04 steel Y1 - 2021 SN - 978-3-030-75381-8 SN - 978-3-030-75380-1 SN - 978-3-030-75383-2 U6 - https://doi.org/10.1007/978-3-030-75381-8_143 SN - 2367-1696 SP - 1701 EP - 1711 PB - Springer, Cham ET - 1 ER - TY - GEN A1 - Piott, Michael A1 - Werber, Alexandra A1 - Schleuss, Leander A1 - Doynov, Nikolay A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - A study of the heat transfermechanism in resistance spot welding of aluminum alloys AA5182 and AA6014 T2 - International Journal of Advanced Manufacturing Technology N2 - This work investigates heat transfer mechanism of aluminum resistance spot welding process. The main target is to determine thermal contact conductance and heat transfer coefficients for natural convection and thermal radiation at ambient air and forced convection inside the water-cooled electrodes. For this purpose, the heat transfer of hot sheets in a welding gun for aluminum alloys AA5182 and AA6014 is analyzed experimentally and numerically. The transient temperature field is measured by several thermocouples in a simplified experimental setup. Subsequent thermal-mechanical coupled finite element simulations of the experiments were used to calibrate the heat transfer coefficients. The heat transfer coefficient for natural convection and thermal radiation to ambient air is 13 W m2 K and the heat transfer coefficient for forced convection of electrode water-cooling is 25,000 W m2 K. The results indicate that the thermal contact conductance can be assumed ideal for welding process. Additionally, the finite element model is validated by the measured and calculated dissipated heat due to forced convection. Finally, a sensitivity analysis is performed to compare the influence of maximum and minimum heat transfer coefficients of forced convection (water-cooling) on transient temperature field and dissipated heat of sample AA5182. KW - Aluminum resistance spot welding KW - Heat transfer KW - FE simulation KW - Thermal contact conductance KW - Electrode water-cooling Y1 - 2020 U6 - https://doi.org/10.1007/s00170-020-05650-x SN - 0268-3768 SN - 1433-3015 VL - Vol. 111 SP - 263 EP - 271 ER - TY - GEN A1 - Shapovalov, Oleg T1 - Метод безэлектродного контактирования пьезоэлемента в иммерсионном преобразователе для использования в высокотемпературных проводящих жидких средах T2 - Pribory i Tekhnika Eksperimenta / Приборы и Техника Эксперимента N2 - Представлены концепция и тестирование новой модификации изобретенного ранее ультразвукового преобразователя для толщинометрии в высокотемпературных иммерсионных средах. Суть модификации заключается в удалении нижнего электрода пьезоэлемента и использовании электропроводности окружающей жидкости для передачи электрического заряда на контактирующую с жидкостью поверхность пьезоэлемента. Благодаря отсутствию заземляющего электрода разработанная технология обеспечивает заметное повышение точности прибора, а также значительное улучшение отношения сигнал/шум. Кроме того, предложенная модификация позволяет снизить нижнюю границу измеряемой толщины. Это обеспечивается за счет укорочения посылаемого ультразвукового импульса благодаря минимизации рассеяния излучаемого сигнала, обусловленного в исходном варианте нижним электродом. Таким образом, несмотря на некоторые отдельные сложности, которые могут возникнуть при применении модифицированного преобразователя, представленная концепция обеспечивает заметное улучшение качества измерения. Y1 - 2022 UR - https://sciencejournals.ru/view-article/?j=pribory&y=2022&v=0&n=1&a=Pribory2201022Shapovalov U6 - https://doi.org/10.31857/S0032816222010220 SN - 0032-8162 IS - 1 SP - 154 EP - 158 ER - TY - GEN A1 - Shapovalov, Oleg T1 - A Method of Electrodeless Contacting of a Piezo Material in a High-Temperature Resistant Ultrasonic Transducer for Use in the Immersion Technique in Electrically Conductive Liquids T2 - Instruments and Experimental Techniques N2 - This work presents the concept and testing of a new modification of a previously invented high-temperature resistant ultrasonic transducer for immersive thickness measurement. The modification lies in the removal of a front electrode and using the electrical conductivity of the surrounding liquid to transfer the electrical charge onto the liquid-contacted surface of a piezo actuator. By not using a front electrode the developed technology provides a considerable increase of the transducer sensitivity, as well as a significant improvement of the signal-to-noise ratio. Furthermore, it reduces the minimum measurable thickness by shortening the impulse due to minimization of the scattering of emitted signal caused by front electrode. Therefore, despite some isolated complications, which could arise in special cases of application of modified transducer, the presented concept provides an appreciable improvement of the measuring quality. Y1 - 2022 U6 - https://doi.org/10.1134/S0020441222010201 SN - 0020-4412 VL - 65 IS - 1 SP - 175 EP - 178 ER - TY - GEN A1 - Jokisch, Torsten A1 - Doynov, Nikolay A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Analysis of Local Strain Evolution during Electron Beam Welding of Hot Crack Sensitive Nickel Base Conventionally Cast Alloy 247 LC CC T2 - Journal of Materials Engineering and Performance N2 - Among different joining methods, the electron beam welding is recently applied for manufacturing of turbine components from temperature-resistant nickel-based conventionally cast Alloy 247 LC CC. However, the high tendency to hot cracking, in particular the formation of solidification cracks, remains a major challenge. Experiments indicate a significant reduction in hot cracks if the welding is performed outside the common welding parameter range. To understand these observations, a study of local thermo-mechanical conditions during electron beam welding of Alloy 247 samples was carried out using numerical simulations. The results were subsequently compared with reference test welds. For this purpose, a finite element model for coupled transient thermal and mechanical analysis was created and used. The work presents a comparative analysis of the evolution of strain components in brittle temperature range during cooling, considering the distribution and orientation of the cracks. Various relations between local strain kinetics and crack appearance, with notable influence of the plastic strain vector, were observed. Finally, the aspects of assessment of hot crack susceptibility with aid of thermo-mechanical welding simulation are discussed. KW - computational welding mechanics KW - electron beam welding KW - hot crack susceptibility KW - modeling of welding and joining KW - nickel-based alloys Y1 - 2022 U6 - https://doi.org/10.1007/s11665-022-06660-4 SN - 1544-1024 VL - 31 IS - 9 SP - 7009 EP - 7017 ER - TY - GEN A1 - Morozova, Iuliia A1 - Kehm, Christian A1 - Obrosov, Aleksei A1 - Yang, Yitong A1 - Miah, Kamal Uddin Mohammad A1 - Uludintceva, Elena A1 - Fritzsche, Sebastian A1 - Weiß, Sabine A1 - Michailov, Vesselin T1 - On the Heat Treatment of Selective-Laser-Melted 316L T2 - Journal of Materials Engineering and Performance N2 - The effect of heat treatment at various temperatures (650, 850, 1050, and 1100°C) and dwell times (10 min and 1 h) on the metallurgical and microstructural evolution as well as on the related tensile properties of stainless steel 316L processed by selective laser melting (SLM) has been systematically evaluated. The metallurgical and microstructural features such as defects, stability of the columnar–cellular structure and substructure, second phase particles, and phase transformation imparted by SLM and heat treatment have been discussed. It has been shown that the processing conditions specific to SLM significantly alter the kinetics of phase evolution compared to standard welding techniques which affects the accuracy of the prediction. The influence of these characteristics on tensile properties and hardness was elucidated. It was disclosed that with increasing heat treatment temperature there was a gradual increase in elongation but a decrease in strength related to the dislocation density and the development of the microstructure. KW - 316L KW - grain structure KW - phase evolution KW - SLM KW - tensile properties Y1 - 2023 U6 - https://doi.org/10.1007/s11665-022-07404-0 SN - 1544-1024 VL - 32 (2023) IS - 10 SP - 4295 EP - 4305 ER - TY - GEN A1 - Morozova, Iuliia A1 - Królicka, Aleksandra A1 - Obrosov, Aleksei A1 - Yang, Yitong A1 - Doynov, Nikolay A1 - Weiß, Sabine A1 - Michailov, Vesselin T1 - Precipitation phenomena in impulse friction stir welded 2024 aluminium alloy T2 - Materials Science and Engineering: A N2 - Microhardness variations across the friction stir welded (FSW) and impulse friction stir welded (IFSW) AA2024–T351 joints have been elucidated by the transformations of the S–Al2CuMg phase with a special focus on a distinguished hardness peak within the heat-affected zone (HAZ) of the impulse welds. The increase in hardness within the stir zone (SZ) originated from the partial re-precipitation of the initial Guinier-Preston-Bagaryatsky zones (GPB) and metastable S needles, previously dissolved.) Formation and growth of stable S precipitates via coalescence accounted for the softening through the thermo-mechanically affected zone (TMAZ). The peak strengthening within the HAZ of the IFSW joints was mainly caused by the dense needle-shaped S particles, which can be explained by a mutual influence of the process specific temperature and strain cycles. Dislocations and subgrain boundaries introduced to the material due to plastic deformation facilitated the nucleation of strengthening S precipitates in the HAZ. It demonstrates that the impact of deformation should be considered by the characterization of the precipitation development in the HAZ. KW - AA2024 KW - impulse friction stir welding KW - microhardness KW - s precipitation KW - thermal cycle KW - deformation Y1 - 2022 U6 - https://doi.org/10.1016/j.msea.2022.143617 SN - 0921-5093 SP - 1 EP - 11 ER - TY - GEN A1 - Hagen, Christian A1 - Klinkenberg, Franz-Josef A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Resistance spot welding of dissimilar material joints with a cold-gas-sprayed inlayer T2 - The International Journal of Advanced Manufacturing Technology N2 - In this publication, cold gas spraying (CGS) is investigated as an enabler for aluminum-steel joints. Using a powder-based coating process to adhere a steel layer to an aluminum substrate allows a steel component to be welded to the deposited layer by resistance spot welding. This method permits the metallurgical connection between similar materials to be separated, while mechanical bonding ensures the connection at the dissimilar aluminum-to-inlayer interface. A modification of the porous CGS layer, as well as the creation of the remelted zone in the aluminum, can be observed during the resistance spot welding process. Electron backscatter diffraction (EBSD) analyses show that the severely prestressed particles in the CGS coating recrystallize, which coincides with a decrease in defect density and hardness in the heat-affected zone. Microscopy of the aluminum substrate shows the creation of metallurgical pores as well as the expansion of pores attributed to the casting process. The rise in remelted aluminum hardness and decrease in the heat-affected zone of the CGS layer indicate the formation of a metallurgical notch. KW - resistance spot weld KW - rsw KW - cold gas spray KW - cgs KW - inlayer KW - dissimilar joint KW - aluminium-steel weld Y1 - 2023 UR - https://link.springer.com/article/10.1007/s00170-023-11897-x U6 - https://doi.org/10.1007/s00170-023-11897-x SN - 1433-3015 SN - 0268-3768 ER - TY - CHAP A1 - Doynov, Nikolay A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Unterstützung beim thermischen Richten von geschweißten Großstrukturen durch praktikable Computersimulationen T2 - DVS Congress 2018 : Große Schweißtechnische Tagung, DVS-Studentenkongress, Vorträge der Veranstaltungen in Friedrichshafen am 17. und 18. September 2018 N2 - Unterstützung beim thermischen Richten von geschweißten Großstrukturen durch praktikable Computersimulationen KW - Thermisches Richten KW - Großstrukturen KW - Simulation KW - Umformen KW - Schiffbau KW - Richten Y1 - 2018 SN - 978-3-96144-036-8 SP - 364 EP - 369 PB - DVS Media GmbH CY - Düsseldorf ER - TY - CHAP A1 - Ginzburg, Svetlana A1 - Morozova, Iuliia A1 - Kloshek, Alexander A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Schweißen von Stahl mit Nanopartikel modifizierten Fülldrähten - Schweißnahtgefüge und -eigenschaften T2 - DVS Congress 2018 : Große Schweißtechnische Tagung, DVS-Studentenkongress, Vorträge der Veranstaltungen in Friedrichshafen am 17. und 18. September 2018 N2 - Analyse des Schweißnahtgefüges und -eigenschaften beim Schweißen von Stahl mit Nanopartikel modifizierten Fülldrähten KW - Schweißen KW - Fülldraht KW - Nano KW - Nanotechnologie KW - Stahl KW - Gefüge Y1 - 2018 SN - 978-3-96144-036-8 SP - 40 EP - 46 PB - DVS Media GmbH CY - Düsseldorf ER - TY - CHAP A1 - Stapelfeld, Christoph A1 - Launert, Benjamin A1 - Pasternak, Hartmut A1 - Doynov, Nikolay A1 - Michailov, Vesselin T1 - The Influence of Geometrical and Welding Imperfections on the Strength of Stiffened Structures T2 - High Performance Steel Structures Research Council (HPSSRC), Delft, Netherlands, 2018 N2 - The strength calculation of stiffened plates and shells via finite element simulation has been part of the state of the art for a long time. Geometrical nonlinearities as well as the nonlinear material behavior are considered within the calculation. To simplify, both types of imperfections, geometrical and structural ones, are mostly combined in these strength calculations being considered as equivalent geometrical imperfections. Values for standard cases are included in EN 1993-1-5 in case of plated structures or 1-6 in case of shells. A second possibility is the separate definition of fabrication tolerances and residual stresses, as far as they are known. With increasing complexity of the structure, less information are however available on geometrical and particularly structural imperfections. Nevertheless, by means of a more realistic consideration of these values, the actual ultimate load can be determined significantly more exactly and the performance of high performance steel structures is increased. In the investigated cases, deformations and stresses arise mainly due to welding. Therefore, the topic of this article is the application of an analytical numerical hybrid model for predicting imperfections induced by welds. This is presented on an example of a stiffened steel structure and a subsequent ultimate load calculation. At the beginning the analytical model, its physical basis as well as the physical interrelationships are introduced and explained. This is followed by the explanation of the coupling procedure between the analytical model and the numerical calculation for the calculation of weld-induced deformations and residual stresses. The significance of the hybrid model is proven by means of a few sample applications. For a realistic determination of the weld imperfections in the investigated stiffened structure, the coupled hybrid model is used afterwards. An ultimate load analysis gives information about the load carrying behavior under axial loading. The results are compared with the results of an ultimate load analysis from a literature example assuming different eigenvalues with different scaling. The results underline the potential additional utilization of load bearing capacity by this new approach. KW - Welding KW - Stresses KW - Strains KW - Imperfections KW - Stiffened Structures KW - Distortions Y1 - 2018 UR - https://www-docs.b-tu.de/fg-stahlbau/public/Fachgebiet_Stahlbau/publikationen/Workshop_Proceedings_of_HPSSRC-updated_cs.pdf SP - 191 EP - 201 ER - TY - GEN A1 - Hantelmann, Cord A1 - Fritzsche, Sebastian A1 - Michailov, Vesselin A1 - Boywitt, Ralf A1 - Risse, Steffen A1 - Pöge, Matthias A1 - Vogelsang, Jörg A1 - Cramer, Heidi T1 - Geschweißte Konstruktionen aus Aluminiumschaumsandwich T2 - Schweißen und Schneiden N2 - Im vorgestellten Projekt wurden werkstoff- und konstuktionsgerechte Knotenformen aus Aluminiumschaumsandwich (engl. Aluminium Foam Sandwich, AFS) gestaltet und mit unterschiedlichen Schweißverfahren wie dem Metall-Inertgasschweißen und dem Rührreibschweißen gefügt und geprüft. Im Rahmen der Arbeiten stand dabei die schweißtechnische Verarbeitung von AFS mit anderen Produkten, wie den Strangpressprofilen oder dem Aluminiumvollmaterial, und deren Beanspruchbarkeit im Vordergrund. In umfangreichen Untersuchungen wurden hierzu sowohl die Verbindugsknoten selbst als auch der Sandwichverbund und die Einzelkomponenten des Sandwich, Schaum und Decklagen, anhand der statischen Festigkeit und Schwingfestigkeit bewertet. Zusätzlich wurden innere Schädigungsmechanismen betrachtet. Mit experimentellen und numerischen Nachweismethoden konnte die anwendungssichere Knotengestaltung, -anbindung und -berechnung der unterschiedlichen Verbindungstypen umgesetzt werden. Die Ergebnisse wurden im Rahmen der Nachweisführung gegenübergestellt und hinsichtlich eines praxisgerechten Einsatzes nach FKM-Richtlinie bzw. Eurocode9 bewertet. Mit den ermittelten Ergebnissen wurde die bisherige Gestaltungs- und Fügerichtlinie um neue Verbindungstypen erweitert. KW - Festigkeit KW - Reibschweißen KW - Richtlinien KW - Schutzgasschweißen KW - Werkstofffragen KW - Werkstoffkombination Y1 - 2023 SN - 0036-7184 VL - 75 IS - 12 SP - 912 EP - 922 ER - TY - GEN A1 - Evdokimov, Anton A1 - Doynov, Nikolay A1 - Ossenbrink, Ralf A1 - Obrosov, Aleksei A1 - Weiß, Sabine A1 - Michailov, Vesselin T1 - Thermomechanical laser welding simulation of dissimilar steel-aluminum overlap joints T2 - International Journal of Mechanical Sciences N2 - Mixing of steel and aluminum within the weld pool during keyhole laser welding results in a complex dissimilar microstructure, which in turn, initiates a shift in weld metal mechanical properties. In this study, a numerical model for computation of distortions in laser-welded dissimilar overlap joints (austenitic stainless steel 304 – 6082-T6 aluminum alloy), which considers properties of the mixed steel-aluminum weld metal was developed. The required yield strength, Young's modulus, and strain hardening exponent of the weld metal were experimentally determined using the indentation technique coupled with energy-dispersive X-ray spectroscopy. The designed material model calculates the weld elastic-plastic properties as a function of the aluminum concentration. The softening of the alloys in the heat-affected zone was determined by physical simulations and considered as a function of maximum temperature. Computed and measured distortions showed good agreement for various welding regimes with an average deviation of 18.4%. The sensitivity analyses indicated that the application of the developed weld material model significantly improves the accuracy of the thermomechanical simulations. Y1 - 2021 U6 - https://doi.org/10.1016/j.ijmecsci.2020.106019 SN - 1879-2162 VL - 190 ER - TY - GEN A1 - Piott, Michael A1 - Werber, Alexandra A1 - Schleuss, Leander A1 - Doynov, Nikolay A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Numerical and experimental analysis of heat transfer in resistance spot welding process of aluminum alloy AA5182 T2 - International Journal of Advanced Manufacturing Technology N2 - In this work, a numerical model and experiments are used to investigate heat transfer processes during resistance spot welding process of aluminum. For this purpose, calibrated heat transfer conditions and thermal contact conductance are transferred from a previous work to a coupled thermal-electrical-mechanical finite element model. First, all domains of the numerical model are validated by an experimental study. The experimental setup includes the measurement of current, voltage drops, electrode force, electrode displacement, and temperatures while two sheets of aluminum alloy AA5182 are joined. Computational results show that most of the generated Joule heat (78%) is stored in the electrodes or transferred to cooling water until the end of weld time. Heat transfer by natural convection and thermal radiation is very small and can in general be neglected for complete process. Afterwards, the influence of electrode water-cooling on welding process is investigated numerically. The results indicate that the generation of Joule heat and thermal energy of the sheets during weld time is only slightly affected by electrode water-cooling. As a consequence, water-cooling conditions do not affect nugget formation. In contrast, electrode water-cooling highly influences cooling conditions during hold time. KW - Aluminum resistance spot welding KW - Heat transfer KW - FE-simulation KW - Electrode water-cooling KW - Instrumented experiments Y1 - 2020 U6 - https://doi.org/10.1007/s00170-020-06197-7 SN - 0268-3768 SN - 1433-3015 VL - Vol. 111 IS - 5-6 SP - 1671 EP - 1682 ER - TY - GEN A1 - Naumov, Anton A1 - Morozova, Iuliia A1 - Rylkov, Evgenii A1 - Obrosov, Aleksei A1 - Isupov, Fedor A1 - Michailov, Vesselin A1 - Rudskoy, Andrey I. T1 - Metallurgical and Mechanical Characterization of High-Speed Friction Stir Welded AA 6082-T6 Aluminum Alloy T2 - Materials N2 - The objective of this study was to investigate the effect of the high welding speed on the mechanical properties and their relations to microstructural characteristics of butt friction stir welded joints with the use of 6082-T6 aluminum alloy. The aluminum sheets of 2.0 mm thick were friction stir welded at low (conventional FSW) and high welding speeds (HSFSW) of 200 and 2500 mm/min, respectively. The grain size in the nugget zone (NZ) was decreased; the width of the softened region was narrowed down as well as the lowest microhardness value located in the heat-affected zone (HAZ) was enhanced by HSFSW. The increasing welding speed resulted in the higher ultimate tensile strength and lower elongation, but it had a slight influence on the yield strength. The differences in mechanical properties were explained by analysis of microstructural changes and tensile fracture surfaces of the welded joints, supported by the results of the numerical simulation of the temperature distribution and material flow. The fracture of the conventional FSW joint occurred in the HAZ, the weakest weld region, while all HSFSW joints raptured in the NZ. This demonstrated that both structural characteristics and microhardness distribution influenced the actual fracture locations. KW - high-speed friction stir welding (HSFSW) KW - aluminum alloy KW - remnant oxide line (ROL) KW - microstructural characteristics KW - mechanical properties KW - fracture behavior KW - FEM Y1 - 2019 UR - https://www.mdpi.com/1996-1944/12/24/4211 U6 - https://doi.org/10.3390/ma12244211 SN - 1996-1944 VL - 12 IS - 24 ER - TY - GEN A1 - Turabov, Dashqin A1 - Evdokimov, Anton A1 - Nikitin, Alexander A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Vorhersage des Elektrodenverschleißes beim Widerstandspunktschweißen von Aluminium durch dynamische Widerstandsmessung T2 - DVS Congress 2023, Große Schweißtechnische Tagung, DVS Campus ; Kurzfassungen der Vorträge der Veranstaltung in Essen vom 11. bis 14. September 2023 ; (Langfassungen der Beiträge auf USB-Karte) N2 - Das Widerstandspunktschweißen ist ein weit verbreitetes Schweißverfahren, insbesondere bei der Karosserieherstellung in der Automobilbranche. Im Hinblick auf den Leichtbau werden zunehmend Aluminiumlegierungen verwendet. Das Hauptproblem beim Widerstandspunktschweißen von Aluminiumlegierungen ist der schnelle Elektrodenverschleiß. Dadurch wird die Qualität und Effizienz des Schweißprozesses beeinträchtigt. Die Elektrodenstandmenge ist erreicht, wenn die Schweißverbindung eines der Qualitätskriterien nicht erfüllt. Um die Elektrodenstandmenge zu ermitteln, werden in der Industrie im Rahmen der Schweißnahtqualifizierung zeit- und ressourcenaufwändige Methoden, u. a. zerstörende Prüfmethoden, verwendet. In dieser Arbeit wird eine Methode zur Vorhersage des kritischen Elektrodenverschleißes beim Aluminiumschweißen durch Messung des dynamischen Widerstandes vorgeschlagen. In umfangreichen Versuchsreihen an einer automobiltypischen Al-Legierung der 5000er Gruppe wurden dynamische Widerstandsmessungen durchgeführt. Aus den Widerstandsmesswerten konnte ein Indikator ermittelt werden, welcher auf das Auftreten von Poren in Schweißverbindung und auf einen bald auftretenden kritischen Elektrodenverschleiß hinweist. Y1 - 2023 UR - https://www.dvs-ev.de/call4papers/abstract.cfm?vid=116&pid=7816 SN - 978-3-96144-230-0 VL - 389 / 2023 SP - 780 EP - 787 PB - DVS Media GmbH CY - Düsseldorf ER - TY - GEN A1 - Evdokimov, Anton A1 - Obrosov, Aleksei A1 - Ossenbrink, Ralf A1 - Weiß, Sabine A1 - Michailov, Vesselin T1 - Mechanical properties of dissimilar steel-aluminum weld T2 - Materials Science and Engineering: A N2 - Knowledge of the properties of dissimilar welds is of great significance for the development of multi-material lightweight structures. In this study, stainless steel (1.4301) and aluminum alloy (6082-T6) sheets were welded in overlap configuration in keyhole mode. The resulting weld metals were investigated with respect to their mechanical properties. Several samples were cut out of different locations along the welds and their cross-sections were subjected to indentation testing and energy dispersive X-ray (EDS) analysis. Young's modulus E, yield stress σy, and strain hardening exponent n, were determined by means of reverse analysis of the indentation load (P) – depth (h) curves, allowing construction of true stress – true strain relations. An essential increase in yield stress in comparison to the one of the base alloys was observed inside the weld metal. In contrary, Young's modulus and strain hardening exponent of the welds were almost identical to corresponding values of the base steel metal. Due to the sensitivity of yield stress to the aluminum content, slight variations of the welding parameters lead to significant changes in elastic-plastic behavior of the weld metal. KW - Mechanical properties KW - Indentation KW - Reverse analysis KW - EDS measurements KW - Dissimilar steel aluminum welding KW - FEM Y1 - 2018 UR - https://www.sciencedirect.com/science/article/pii/S0921509318303563 U6 - https://doi.org/https://doi.org/10.1016/j.msea.2018.03.019 SN - 0921-5093 VL - Volume 722 SP - 242 EP - 254 ER - TY - GEN A1 - Kazak, Fedor A1 - Schleuß, Leander A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin A1 - Weiß, Sabine T1 - Particularities of testing structured sheet metals in 3-point bending tests T2 - Materials Testing N2 - Thin sheet metals from deep drawing steel DC04 are very often used in the production of car body and case parts. Quality improvement of sheet metal components by new constructive solutions (structuring) as well as adapted joining technology is going on. Structured sheet metals differ from each other by their high bending stiffness. At the same time, they show certain anisotropy due to the structure. Therefore a typical testing method of structured semi-finished parts (single sheet metals, sandwiches)is the bending test. The literature review revealed that in many studies no special demands on tests of structured materials were made. This concerns particularly the structure arrangement, structure direction and structure location of the specimen relative to the mandrel position during bending tests, i. e., the direction of the fixed load relative to the structure. The aim of this study was to determine the influence of the test specification on flexural behavior. In the present paper, honeycomb-structured sheet metals were examined using 3-point bending tests. Bending stiffness and lightweight potential were calculated with respect to the location of load application and compared for different structure arrangements,directions and locations. The influence of the anisotropy on flexural behavior of the honeycomb-patterned sheet metals was moderate. Y1 - 2016 U6 - https://doi.org/10.3139/120.110883 SN - 0025-5300 SN - 2195-8572 VL - 58 IS - 6 SP - 495 EP - 500 ER - TY - GEN A1 - Hantelmann, Cord A1 - Fritzsche, Sebastian A1 - Michailov, Vesselin A1 - Boywitt, Ralf A1 - Risse, Steffen A1 - Paulinus, Dietmar T1 - Einsatz von Aluminiumschaum-Sandwich-Bauteilen in Schweißkonstruktionen T2 - Schweissen und Scheiden Y1 - 2016 SN - 0036-7184 VL - 68 IS - 3 SP - 106 EP - 114 ER - TY - CHAP A1 - Panchenko, Oleg V. A1 - Ivanov, Sergey Y. A1 - Kol'Tsova, Tatyana A1 - Michailov, Vesselin T1 - Survivability of Carbon Nanotubes During Arc Welding T2 - Nanocon 2016, conference proceedings, 8th international conference, October 19th-21st, 2016, Brno, Czech Republic, EU KW - Carbon KW - Arc Welding Y1 - 2017 SN - 978-80-87294-71-0 SP - 59 EP - 63 PB - Tanger CY - Ostrava ER - TY - CHAP A1 - Golubev, Iurii A1 - Morozova, Iuliia A1 - Naumov, Anton A1 - Hantelmann, Cord A1 - Doynov, Nikolay A1 - Michailov, Vesselin T1 - Numerical simulation and experimental investigation on Numerical simulation of 6082-T6 aluminum alloy T2 - Materials Science and Technology 2017, (MS&T17), Pittsburgh, Pennsylvania, USA, October 8-12, 2017, volume 2 N2 - The series of impulse friction stir welding (IFSW) experiments for aluminum alloy 6082-T6 butt joints was performed to obtain micrographs, tensile and hardness test samples and to receive the validation data for a numerical model of the process. Impulse force and frequency were varied to determine the effect of individual process parameters on microstructure evolution and mechanical properties of the welded butt joints. A three-dimensional model was established to simulate temperature distribution, heat generation and contact state between the tool and the workpiece during IFSW. Based on the numerical simulation, the influence of the impulses on heat input, maximum weld temperatures and contact state was found. The combination of impulse force and frequency effected the grain refinement. The influence of impulses on the elongation and hardness of the welded joints during IFSW were determined. KW - Aluminum alloy KW - Numerical simulation Y1 - 2017 SN - 978-1-5108-5058-3 SP - 987 EP - 994 PB - Curran Associates, Inc. CY - Red Hook, NY ER - TY - GEN A1 - Miah, Kamal Uddin Mohammad A1 - Kloshek, Alexander A1 - González-Castaño, Miriam A1 - Kehm, Christian A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Herstellen hocheffektiver Mikroreaktoren durch selektives Laserstrahlschmelzen T2 - DVS Congress 2022, Große Schweißtechnische Tagung, DVS Campus ; Kurzfassungen der Vorträge der Veranstaltung in Koblenz vom 19. bis 21. September 2022 ; (Langfassungen der Beiträge auf USB-Karte) N2 - Das pulverbasierte 3D-Metalldrucken ermöglicht die Fertigung von hochkomplexen Integralbauteilen, die als Trägerstruktur für Mikroreaktoren benutzt werden. Nach einer Beschichtung der Struktur mit einem Katalysatormaterial, können diese Mikroreaktoren höchst effizient für die CO2-Methanisierung eingesetzt werden. Durch die additive Fertigung mit dem selektiven Laserstrahlschmelzen (SLM) wurden adaptierte dreidimensionale periodische Gitterstrukturen mit sehr geringen Wandstärken hergestellt. Diese weisen ein sehr günstiges Verhältnis von Oberfläche zu Volumen (TPMS - Triply periodic minimal surface) auf. Des Weiteren zeigen die TPMS-Strukturen vorteilhafte Strömungseigenschaften, die sowohl für die Beschichtung mit dem Katalysator-Material als auch die Durchströmung mit den Reaktionsmedien im Betrieb essentiell sind. So ist es beispielsweise möglich, durch die Variation der Dimension einer TPMS-Struktur die Oberfläche pro Volumeneinheit, den hydraulischen Durchmesser des Reaktors und somit auch den Transportprozess des Fluids deutlich zu verbessern. Diese Faktoren ermöglichen eine effektivere Gas-Katalysator-Reaktion. Im Vergleich zu Mikroreaktorstrukturen aus den traditionellen Herstellungsverfahren liefern die additiv gefertigten Strukturen sowohl eine höhere CO2-Umwandlungsrate als auch eine CH4-Selektivität innerhalb des diffusionskontrollierten Bereichs. Y1 - 2022 SN - 978-3-96144-189-1 SP - 708 EP - 713 PB - DVS Media GmbH CY - Düsseldorf ER - TY - CHAP A1 - Zhang, Wei A1 - Priefer, Marian A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Neue Möglichkeiten für die Additive Fertigung durch Laser-Pulver-Auftragschweißen T2 - DVS Congress 2017, Große Schweißtechnische Tagung, DVS Studentenkongress, Vorträge der Veranstaltungen in Düsseldorf vom 26. bis 29. September 2017 KW - Laser Additive Fertigung Y1 - 2017 SN - 978-3-96144-008-5 SP - 278 EP - 282 PB - DVS Media CY - Düsseldorf ER - TY - GEN A1 - Hantelmann, Cord A1 - Fritzsche, Sebastian A1 - Michailov, Vesselin A1 - Boywitt, Ralf T1 - Entwicklung geschweißter Konstruktionen aus Aluminiumsandwich T2 - DVS Congress 2022, Große Schweißtechnische Tagung, DVS Campus ; Kurzfassungen der Vorträge der Veranstaltung in Koblenz vom 19. bis 21. September 2022 ; (Langfassungen der Beiträge auf USB-Karte) N2 - Im vorgestellten Projekt wurden werkstoff- und konstruktionsgerechte Knotenformen aus Aluminiumschaumsandwich gestaltet und mit unterschiedlichen Schweißverfahren, wie dem Metall-Inertgas-Schweißen und dem Rührreibschweißen, gefügt und geprüft. In umfangreichen Untersuchungen wurden die Knoten, der Sandwichverbund und die Einzelkomponenten des Sandwich, Schaum und Decklagen, anhand der statischen Festigkeit und Schwingfestigkeit bewertet. Zusätzlich wurden innere Schädigungsmechanismen betrachtet. Mit experimentellen und numerischen Nachweismethoden konnte die anwendungssichere Knotengestaltung, -anbindung und -berechnung der unterschiedlichen Verbindungstypen umgesetzt werden. Die Ergebnisse wurden im Rahmen der Nachweisführung gegenübergestellt und hinsichtlich eines praxisgerechten Einsatzes nach FKM-Richtlinie bzw. Eurocode9 bewertet. Mit den ermittelten Ergebnissen wurde die bisherige Gestaltungs- und Fügerichtlinie um neue Verbindungstypen erweitert. Y1 - 2022 SN - 978-3-96144-189-1 SP - 245 EP - 251 PB - DVS Media GmbH CY - Düsseldorf ER - TY - CHAP A1 - Genchev, Gancho Vladimirov A1 - Doynov, Nikolay A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Schweißtechnische Simulation der lokalen Eigenschaften in der Wärmeeinflusszone von Mehrlagenschweißungen T2 - ANSYS Conference & 33rd CADFEM Users' Meeting, 24. - 26. Juni, Bremen, conference proceedings Y1 - 2015 PB - CADFEM GmbH CY - Grafing ER - TY - CHAP A1 - Ivanov, Sergey Y. A1 - Panchenko, Oleg V. A1 - Karkhin, Victor A. A1 - Michailov, Vesselin T1 - Optimization technique for arc welding of structured sheet T2 - METAL 2015, 24th International Conference on Metallurgy and Materials, conference proceedings, June 3rd-5th 2015, Brno Y1 - 2015 UR - http://konsys2.tanger.cz/files/proceedings/21/papers/3950.pdf SN - 978-80-87294-62-8 PB - Tanger CY - Ostrava ER - TY - CHAP A1 - Golubev, Iurii A1 - Naumov, Anton A1 - Michailov, Vesselin T1 - Developing finite element model of the friction stir welding for temperature calculation T2 - METAL 2014, International Conference on Metallurgy and Materials, May 21 st - 23rd 2014, Brno Y1 - 2014 SN - 978-80-87294-54-3 SP - 1242 EP - 1248 ER - TY - CHAP A1 - Naumov, Anton A1 - Chenikov, Evgenii V. A1 - Golubev, Iurii A1 - Michailov, Vesselin T1 - Research of temperature distribution during friction stir welding of 2 mm Aw 6082 sheets T2 - METAL 2015, 24th International Conference on Metallurgy and Materials, conference proceedings, June 3rd-5th 2015, Brno Y1 - 2015 SN - 978-80-87294-62-8 SP - 651 EP - 653 PB - Tanger CY - Ostrava ER - TY - CHAP A1 - Golubev, Iurii A1 - Naumov, Anton A1 - Chernikov, Evgenii V. A1 - Michailov, Vesselin ED - Mishra, Rajiv S. ED - Mahoney, Murray W. ED - Sato, Yutaka ED - Hovanski, Yuri T1 - Temperature distribution and welding distortion measurements after FSW of Al 6082-T6 sheets T2 - Friction Stir Welding and Processing VIII, 144th Annual Meeting and Exhibition, 15.03.2015, Orlando Y1 - 2015 SN - 978-3-319-48604-8 SN - 978-3-319-48173-9 U6 - https://doi.org/10.1007/978-3-319-48173-9 SP - 289 EP - 295 PB - Springer CY - Cham ER - TY - CHAP A1 - Zhang, Wei A1 - Schramm, Maximilian A1 - Kaneneks, Michael A1 - Michailov, Vesselin A1 - Fleischhauer, Matthias T1 - Laserstrahl-Auftragschweißen mit pulverförmigen keramischen und metallischen Zusatzwerkstoffen zur Herstellung von Gradientenwerkstoffen T2 - Große Schweißtechnische Tagung, Nürnberg, 15. - 17. September 2015 Y1 - 2015 SN - 978-3-945023-46-4 SP - 842 EP - 845 PB - DVS Media CY - Düsseldorf ER - TY - CHAP A1 - Hantelmann, Cord A1 - Fritzsche, Sebastian A1 - Michailov, Vesselin A1 - Paulinus, Dietmar T1 - Einsatz von Aluminiumschaumsandwich in Schweißkonstruktionen T2 - DVS Congress 2014, Große Schweißtechnische Tagung, DVS-Studentenkongress, Vorträge der Veranstaltungen in Berlin am 15. und 16. September 2014 Y1 - 2014 SN - 978-3-945023-03-7 PB - DVS Media GmbH CY - Düsseldorf ER - TY - PAT A1 - Brobeck, Andreas F. W. A1 - Michailov, Vesselin A1 - Ossenbrink, Ralf A1 - Polzin, Ralf A1 - Schleuß, Leander T1 - Rollennahtelektrode N2 - Eine Rollennahtelektrode zur Verwendung beim Rollennahtschweißen umfasst eine segmentförmige Elektrodenfläche (2) zur Anpressung der zu verbindenden Bauteile und zur Einleitung des Schweißstroms und der Schweißspannung. Die Elektrodenfläche (2) ist derart dreieckförmig oder mäanderförmig oder zueinander beabstandet ausgebildet, dass in der ebenen Abwicklung der Elektrodenfläche (2) ein Zickzack-Muster oder ein Wellen-Muster oder ein Steppnaht-Muster oder ein Rechteck-Muster vorliegt. Y1 - 2017 UR - https://depatisnet.dpma.de/DepatisNet/depatisnet?action=pdf&docid=DE102015114937A1 N1 - Offenlegungsschrift ER - TY - CHAP A1 - Doynov, Nikolay T1 - Anwendungsnahe Simulation des thermischen Richtens T2 - Schweißen in der Maritimen Technik und im Ingenieurbau, 16. Tagung, 20./21. April 2016 in Hamburg Y1 - 2016 SP - 78 EP - 88 PB - GSI SLV Nord CY - Hamburg ER - TY - CHAP A1 - Zhang, Wei A1 - Doynov, Nikolay A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin A1 - Scheithauer, Uwe A1 - Michaelis, Alexander T1 - Investigation of thermal shock behaviour of refractory ceramics based on the calcium-aluminate T2 - 14th Biennial Worldwide Congress Unified International Technical Conference on Refractories (UNITECR) 2015, Vienna, Austria, September 15-18, 2015 Y1 - 2015 SN - 978-3-9815813-1-7 CY - Hannover ER - TY - BOOK A1 - Pasternak, Hartmut A1 - Stapelfeld, Christoph A1 - Launert, Benjamin A1 - Michailov, Vesselin A1 - Doynov, Nikolay T1 - Ermittlung der Tragfähigkeit neuartiger stählerner Schalenbauwerke unter realitätsnaher Berücksichtigung des Schweißverzugs Y1 - 2020 SN - 978-3-946885-89-4 PB - Forschungsvereinigung Stahlanwendung e. V. CY - Düsseldorf ER - TY - GEN A1 - Wasilewski, Eric A1 - Kaneneks, Michael A1 - Doynov, Nikolay A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Laserstrahlschweißen – Verzugs- und Kaltrissminimierung durch simulationsbasierte Steuerung T2 - DVD Congress 2020 : Große Schweißtechnische Tagung : DVS Campus : Vorträge der Online-Veranstaltungen vom 14. bis 18. September 2020 N2 - Leichtbau und das Streben nach Ressourcen- und Energieeffizienz fördern in den letzten Jahren vermehrt den Einsatz hochfester Stähle. Das Laserstrahlschweißen dieser Werkstoffe wird in der industriellen Großserienferti-gung zur effizienten Herstellung hochpräziser Bauteile und Komponenten mit höchsten Qualitätsanforderungen eingesetzt. Die Vermeidung schweißbedingter Fehler wie Schweißverzug und Kaltrissbildung sind dabei von ent-scheidender Bedeutung. Konventionelle Anwendungen erfüllen diesen Anspruch derzeit bedingt durch sehr enge Prozesstoleranzen und die Auswahl unkritischer Werkstoffe, was die Potentiale der Fügeverbindung begrenzt. Auf Basis von FE-Schweißprozesssimulationen konnten Konzepte entwickelt werden, welche eine Verzugs- und Riss-minderung durch aktive Steuerung des Laserschweißprozesses ermöglichen. Die zugrundeliegenden Modelle be-rücksichtigen zum einen das schweißbedingte Temperaturfeld, Gefügeumwandlungen und Eigenspannungen für die Berechnung des Verzugs. Zudem wird die lokale Wasserstoffkonzentration berechnet und die Ergebnisse der Schweißprozesssimulation mittels eines Kaltrisstools bewertet, welches werkstoffspezifische Risskriterien enthält. Die Fähigkeit das Verzugs- und Kaltrissverhalten abzubilden, eröffnet die Möglichkeit zur Parametervariation. Aus den erhobenen Daten wurden Konzepte der aktiven Krafteinleitung mit einer dynamischen Werkstückeinspannung abgeleitet, die zu Verzugs- und Kaltrissminimierung führen und die Schweißbarkeit hochfester Werkstoffe fördern. Y1 - 2019 SN - 978-3-96144-098-6 SP - 9 PB - DVS Media GmbH CY - Düsseldorf ER - TY - GEN A1 - Kaneneks, Michael A1 - Kloshek, Alexander A1 - Morozova, Iuliia A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin A1 - Sembol, Ronny T1 - WAAM eines Zwischenstücks für die Bergbauausrüstung T2 - DVS Bericht 2021 N2 - Die lichtbogenbasierte additive Fertigung (WAAM) ist ein vielversprechendes Werkzeug, um die Ersatzteilbereitstellung von schwer verfügbaren oder aufwendig herstellbaren Einzelkomponenten in kürzester Zeit zu gewährleisten. Die Straffung innerbetrieblicher Abläufe sowie die Minimierung von Herstellungs- und Lagerkosten sind eine direkte Folge. Vor dem Einsatz im Betrieb muss sichergestellt werden, dass die Bauteile fehlerfrei additiv herstellbar sind und die mechanischen Eigenschaften den Anforderungen konventionell gefertigter Werkstücke entsprechen. Ein solcher Nachweis konnte am Beispiel eines additiv hergestellten Zwischenstücks für die Bergbauausrüstung mit einer abschließenden Charakterisierung der Werkstoffeigenschaften erfolgreich geführt werden. Das Zwischenstück mit einem Gewicht von ca. 31 kg zur Verbindung von geometrisch unterschiedlichen Profilen wurde ausgehend von einer Grundplatte aus S355-J2+N beidseitig additiv mit einem Massivdraht G3Si1 aufgebaut. Die Ermittlung geeigneter Parameter, Schweißfolgen und Zwischenlagentemperaturen erfolgte experimentell mit begleitenden metallografischen Untersuchungen. Nach erfolgreicher Fertigung wurden die mechanischen Eigenschaften des Zwischenstücks bestimmt sowie die Festigkeit und Zähigkeit mit den geforderten Werkstoffkennwerten des bisher eingesetzten konventionellen Konstruktionsmaterials verglichen. KW - Schweißtechnik KW - WAAM KW - Wire Arc Additiv Manufacturing KW - Additive Fertigung KW - Lichtbogenauftragschweißen Y1 - 2021 UR - https://www.dvs-ev.de/call4papers/abstract.cfm?vid=109&pid=7030 SN - 978-3-96144-147-1 VL - 2021 SP - 315 EP - 323 PB - DVS Media GmbH CY - Düsseldorf ER - TY - CHAP A1 - Schleuß, Leander A1 - Brobeck, Andreas F. W. A1 - Ossenbrink, Ralf A1 - Polzin, Ralf A1 - Michailov, Vesselin T1 - Rollennahtschweißen strukturierter Bleche mit neuartigen Elektroden T2 - Widerstandsschweißen, 23. Sondertagung in Duisburg am 29. und 30. Juni 2016 N2 - Bleche mit regelmäßig angeordneten steifigkeitserhöhenden Strukturen werden zunehmend in Kon-struktionen zur Erhöhung der Steifigkeit dünner Bleche bzw. von kompletten Bauteilen verwendet. Damit diese Bauteile wirtschaftlich verarbeitet werden können, bietet das Rollennahtschweißen mit seinen hohen Prozessgeschwindigkeiten und ohne notwendigen Einsatz von Zusatzwerkstoffen bzw. Schweißhilfsstoffen eine kostengünstige Alternative zu anderen Verfahren. Beim Rollennahtschweißen strukturierter Bleche führen jedoch klassische Rollennahtelektroden zur teilweisen bzw. vollständigen Einebnung der Versteifungselemente, sodass deren positive Wirkung reduziert bzw. vollständig auf-gehoben werden kann. Die geschweißten Bleche haben Wabenstrukturen mit unterschiedlichen Elementtiefen als regelmäßig angeordnete Versteifungselemente. Die Bleche finden vorrangig Anwendung im Fahrzeugbau und im Bauwesen. Aufgrund dieser Branchen und für zukünftige Anwendungen im Wärmetauscher- und Behäl-terbau wurden die Untersuchungen an Werkstoffqualitäten DC04 und X5CrNi 18-10 mit Blechdicken von 0,5 mm und 0,7 mm durchgeführt. Die entwickelten neuartigen Elektroden berücksichtigen die Topologie der Bleche, um eine Einebnung der strukturierten Bleche zu vermeiden. Daher wurden Elektroden mit veränderten Geometrien an den Elektrodenarbeitsflächen gestaltet. Eine der Elektroden besitzt eine periodisch unterbrochene und die zweite eine laterale Profilierung mit in Schweißrichtung nichtlinearer Form der Elektrodenarbeitsfläche. Das Verhalten beim Schweißen wurde in Schweißversuchen bestimmt und Schweißbereichsdiagram-me bzw. Prozessfenster abgeleitet. Die Verbindungseigenschaften wurden durch Metallografie-, Fes-tigkeits-, Druck- und Dichtheitsuntersuchungen validiert. Als Vergleich und Referenz dienen Schweiß-untersuchungen mit konventionellen Rollennahtelektroden. Die Untersuchungsergebnisse zeigen Unterschiede bei den Prozessparametern und der Ausprägung der Verbindung in Abhängigkeit von der geschweißten Struktur, dem ausgewählten Schweißpfad und des geschweißten Werkstoffes gegenüber den Referenzschweißungen. Eine anschließende Optimie-rung führte zu einer vergleichbar guten Schweißnahtqualität sowohl bei Erhalt der Versteifungselemen-te mit den neuen Elektroden als auch bei deren Einebnung mit konventionellen Elektroden in Referenz zu Schweißuntersuchungen am ebenen Blech. Anschließend wurde ein Vergleich der Verbindungsfestigkeiten mit dem Widerstandspunktschweißen und dem Metall-Aktivgas-Schweißen durchgeführt. KW - Rollennahtschweißen KW - Leichtbauelement KW - durchströmbar KW - neuartig KW - Elektrodengeometrie KW - Wärmetauscher Y1 - 2016 SN - 978-3-945023-75-4 SP - 230 EP - 240 PB - DVS Media GmbH CY - Düsseldorf ER - TY - CHAP A1 - Schleuß, Leander A1 - Springer, Katrin A1 - Zoeke, Jörg A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Qualifizierung von wärmearmen MSG-Schweißverfahren für Leichtbaukonstruktionen mit strukturierten Halbzeugen T2 - Internationaler Fachkongress der Schweiß- und Verbindungstechnik Join-Ex 2012 Wien, 10. + 11. Oktober 2012, Congress Center der Messe Wien KW - wärmearm KW - Schweißen KW - strukturiert KW - Steifigkeitserhöhung KW - Hochgeschwindigkeitsaufnahme KW - Temperaturzyklen Y1 - 2012 SP - 75 EP - 83 PB - Schweißtechnische Zentralanstalt e.V. CY - Wien ER - TY - CHAP A1 - Sasse, Ina A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Welding of structured sheet metals with high power fiber laser T2 - Międzynarodowa Sesja Studencka, 30. Mai 2012, Częstochowa/Polen KW - structured sheet metals; laser welding Y1 - 2012 SN - 978-83-87745-69-1 SP - 285 EP - 290 CY - Częstochowa ER - TY - CHAP A1 - Ossenbrink, Ralf A1 - Doynov, Nikolay A1 - Michailov, Vesselin T1 - Welding simulation of aluminium to steel joints by means of arc welding Processes T2 - 10th International Scientific and Technical Conference, Advanced metal materials and technologies (AMMT’2013), June 25–29, Saint Petersburg, 2013 N2 - The object of the present work is the introduction of a welding simulation approach for aluminium to steel welded joints which are realised by short-arc welding. The study is carried out with special emphasis on the simulation of temperature field by means of conduction solution, on the applicability of different metallurgical models as well as the aspects of the mechanical simulation of the residual welding stresses and distortions. As result an approved heat source model is suggested and the calibration parameters are presented. For the modelling of the microstructure and corresponding thermomechanical material properties in the heat affected zone different material models are validated. They are used to simulate the welding residual stresses and distortions. Furthermore, the welding simulation of a real component as well as a simulation study of different welding scenarios is presented. KW - Welding simulation; aluminium steel; welding Processes Y1 - 2013 SP - 523 EP - 528 PB - Izdat. Polytechn. Univ. CY - Saint Petersburg, Russia ER - TY - CHAP A1 - Karkhin, Victor A. A1 - Levchenko, A. M. A1 - Homich, P. N. A1 - Michailov, Vesselin T1 - Computer-Aided Express Determination of Diffusible Hydrogen in Deposited Weld Metal T2 - International Conference on Total Welding Management in Industrial Applications, 3rd JOIN Conference, Lappeenranta, August 21 - 24, 2007 KW - diffusible Hydrogen KW - deposited weld metal Y1 - 2007 SN - 978-952-214-413-3 SP - 252 EP - 262 CY - Lappeenranta ER - TY - CHAP A1 - Genchev, Gancho Vladimirov A1 - Doynov, Nikolay A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Simulation des Mehrlagenschweißens unter Berücksichtigung der Gefügeumwandlungen T2 - Conference proceedings, 2012 - ANSYS Conference & 30. CADFEM Users' Meeting, 24. - 26. Oktober 2012, Kassel N2 - Der Konferenzvortrag stellt das entwickelte M-STAAZ Modell vor. Mit dem M-STAAZ lässt sich in der FE-Simulation die Änderung der Werkstoffkennwerte bei mehrmaliger Temperaturbelastung wie in der WEZ von Mehrlagenschweißungen berücksichtigen. KW - Simulation des Mehrlagenschweißens KW - Gefügeumwandlungen KW - M-STAAZ Modell Y1 - 2012 UR - http://www.usersmeeting.com/rueckblick/acum-2012.html UR - http://www.cadfem.de/fileadmin/shop/um/ACUM2012-DVD-Inhaltsverzeichnis.pdf SP - Art. 2.2.9 PB - CADFEM GmbH CY - Grafing ER - TY - CHAP A1 - Genchev, Gancho Vladimirov A1 - Ossenbrink, Ralf A1 - Doynov, Nikolay A1 - Michailov, Vesselin T1 - Material Properties of the HAZ of Multi-Pass Welded Joints from low alloyed Steel T2 - Junior Euromat 2012, Paperlist KW - material properties of the heat affected zone; multi-pass welds Y1 - 2012 UR - http://wiki.dgm.de/wwiki/wiki/Junior-Euromat%202012%20-%20Paperlist SP - A297 ER - TY - CHAP A1 - Genchev, Gancho Vladimirov A1 - Doynov, Nikolay A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Bewertung der relevanten Einflussfaktoren auf die Gefügeumwandlungen und thermomechanischen Eigenschaften bei komplexen Temperaturbelastungen T2 - ANSYS Conference & 29. CADFEM Users' Meeting 2011, conference proceedings, 19. - 21. October 2011, Stuttgart, ICS N2 - Der Vortrag stellt die Identifizierung und Bewertung der relevanten Einflussfaktoren auf die Gefügeumwandlungen und auf die thermomechanischen Werkstoffkennwerte bei komplexen Temperaturbelastungen vor. Dies erfolgt durch physikalische Simulation der Gefüge in der WEZ von Mehrlagenschweißungen und Aufnahme von Dilatometerkurven und Spannungs-Dehnungskurven. Es wurden einflussarme Kombination von Temperaturzyklen und weitere mit starkem Einfluss auf die Gefügeumwandlung identifiziert. Hinweise zu den erforderlichen Werkstoffkennwerten für die numerische Schweißsimulation wurden gegeben. KW - Gefügeumwandlungen bei mehrmaliger Temperatureinwirkung KW - thermomechanische Eigenschaften KW - Simulation des Mehrlagenschweißens Y1 - 2011 UR - http://www.usersmeeting.com/rueckblick/acum-2011.html UR - http://www.cadfem.de/fileadmin/shop/um/ACUM2011-DVD-Inhaltsverzeichnis.pdf SN - 3-937523-08-1 PB - CADFEM GmbH CY - Grafing ER - TY - CHAP A1 - Brand, M. A1 - Petz, M. A1 - Tutsch, R. A1 - Wohlfahrt, Helmut A1 - Michailov, Vesselin T1 - Numerische Simulation und Verifikation des Bauteilverzugs beim Schweißen unter Verwendung optischer Feldmeßmethoden T2 - Conference proceedings, 21st CAD-FEM Users' Meeting 2003, International Congress on FEM Technology, 12. - 14. November 2003, im Hotel Dorint Sanssouci Berlin, Potsdam KW - Numerische Verzugssimulation; optische Feldmeßmethoden; Y1 - 2003 SN - 3-937523-00-6 N1 - Bericht 2.4.6 PB - CAD-FEM GmbH CY - Grafing bei München ER - TY - CHAP A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Vorhersage der Härteverteilung beim Schweißen mit Hilfe der numerischen Simulation T2 - Conference proceedings, 21st CAD-FEM Users' Meeting 2003, International Congress on FEM Technology, 12. - 14. November 2003, im Hotel Dorint Sanssouci Berlin, Potsdam KW - Numerische Simulation KW - Härteverteilung beim Schweißen Y1 - 2003 SN - 3-937523-00-6 N1 - Bericht 2.4.3 PB - CAD-FEM GmbH CY - Grafing bei München ER - TY - CHAP A1 - Sasse, Ina A1 - Schleuß, Leander A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Fügen strukturierter Bleche - Remote-Laserstrahlschweißen im Vergleich zum Widerstandspunktschweißen T2 - DVS Congress 2013, Große Schweißtechnische Tagung, DVS-Studentenkongress KW - strukturierte Bleche; Remote; Laserstrahlschweißen; Widerstandspunktschweißen Y1 - 2013 SN - 978-3-87155-614-2 SP - 98 EP - 103 PB - DVS-Verlag CY - Düsseldorf ER - TY - GEN A1 - Baena-Moreno, Francisco Manuel A1 - González-Castaño, Miriam A1 - Navarro de Miguel, Juan Carlos A1 - Miah, Kamal Uddin Mohammad A1 - Ossenbrink, Ralf A1 - Odriozola, José Antonio A1 - Arellano-Garcia, Harvey T1 - Stepping toward Efficient Microreactors for CO2 Methanation: 3D Printed Gyroid Geometry T2 - ACS Sustainable Chemistry & Engineering N2 - This work presents a comparative study towards the development of efficient micro-reactors based on 3D-printed structures. Thus, the study evaluates the influence of the metal substrate geometry on the performance of structured catalysts for the CO2 methanation reaction. For this purpose, 0.5%Ru–15%Ni/MgAl2O4 catalyst is wash coated over two different micro-monolithic metal substrates: a conventional parallel channel honeycomb structure and a novel 3D-printed structure with a complex gyroid geometry. The effect of the metal substrate geometry is analyzed for several CO2 sources including ideal flue gas atmospheres, the presence of residual CH4 and CO in the flue gas, as well as simulated biogas sources. The advantages of the gyroid-3D complex geometries over the honeycomb structures are shown for all evaluated conditions, providing at the best-case scenario a 14% improvement of CO2 conversion. Moreover, this contribution shows that systematically tailoring geometrical features of structured catalysts becomes an effective strategy to achieve improved catalysts performances independent of the flue gas composition. By enhancing the transport processes and the gas-catalyst interactions, the employed gyroid 3D metal substrates enable boosted CO2 conversions and greater CH4 selectivity within diffusional controlled regimes. KW - CO2 methanation KW - gyroid geometry KW - CH4 selectivity KW - gyroid-3D complex Y1 - 2021 U6 - https://doi.org/10.1021/acssuschemeng.1c01980 SN - 2168-0485 VL - 9 IS - 24 SP - 8198 EP - 8206 ER - TY - CHAP A1 - Hantelmann, Cord A1 - Fritzsche, Sebastian A1 - Michailov, Vesselin A1 - Boywitt, Ralf T1 - Einsatz von Aluminiumschaumsandwich in Schweißkonstruktionen T2 - DVS Congress 2017 : Große Schweißtechnische Tagung : DVS-Studentenkongress : Vorträge der Veranstaltungen in Düsseldorf vom 26. bis 29. September 2017 N2 - In der vorgestellten Arbeit wird die Anwendbarkeit von Aluminiumschaumsandich in Schweißkonstruktionen vorgestellt. Systematische Betrachtungen zur Schweißbarkeit mittels Laserstrahlschweißen, MSG - Kurzlichtbogen und Rührreibschweißen sowohl im geschäumten als auch im ungeschäumten Zustand werden beschrieben. Dazu wurden verschiedene Knotenformen wie I-Stoß- bzw. T-Stoßverbindungen hergestellt und deren mechanischtechnologische Eigenschaften ermittelt. Neben der quasistatischen Prüfung, wurde jede Ausführungsform des Knotens auf deren Schwingfestigkeit hin geprüft und die Anwendbarkeit bestehender Regelwerke wie die FKMRichtlinie oder der Eurocode 9 für die Nachweisführung betrachtet. Die Ergebnisse sind abschließend in einem Gestaltungskatalog als Hilfsmittel für den Konstrukteur zusammengefasst. Parallel dazu wurden die experimentellen Untersuchungen mittels FEM begleitet. Es wird die FE-Modellentwicklung für die Berechnung des Sandwichverbundes an sich als auch von Fügeknoten dargestellt wie auch die Modellvalidierung mit einem Musterbauteil aus einer Hubarbeitsbühne. KW - Aluminiumschäume KW - FE-Simulation KW - Aluminiumschaumsandwich KW - Schweißkonstruktionen Y1 - 2017 SN - 978-3-96144-008-5 SP - 173 PB - DVS Media CY - Düsseldorf ER - TY - CHAP A1 - Golubev, Iurii A1 - Doynov, Nikolay A1 - Hantelmann, Cord A1 - Michailov, Vesselin T1 - Wärmequellemodell und FE-Temperaturfeldsimulation für das Rührreibschweißen T2 - DVS Congress 2017 : Große Schweißtechnische Tagung : DVS-Studentenkongress : Vorträge der Veranstaltungen in Düsseldorf vom 26. bis 29. September 2017 KW - Wärmequellemodell KW - FE-Temperaturfeldsimulation KW - Rührreibschweißen Y1 - 2017 SN - 978-3-96144-008-5 SP - 112 PB - DVS Media CY - Düsseldorf ER - TY - CHAP A1 - Schleuß, Leander A1 - Brobeck, Andreas F. W. A1 - Ossenbrink, Ralf A1 - Polzin, Ralf A1 - Michailov, Vesselin T1 - Neuartige Elektroden zum Rollennahtschweißen mit nichtlinearem Schweißpfad T2 - Große Schweißtechnische Tagung, 15.-17.09.15 N2 - Beim Rollennahtschweißen von Blechen mit eingebrachten Versteifungselementen wie Sicken oder regelmäßig angeordneten Strukturen führen lineare Schweißpfade unter Verwendung klassischer Rollenelektroden zur teilweisen bzw. vollständigen Einebnung dieser Versteifungselemente. Dadurch kann die positive Wirkung der Versteifungselemente reduziert bzw. vollständig aufgehoben werden. Somit müssen neue Wege für das Rollennahtschweißen von gesickten oder strukturierten Blechen erarbeitet werden. Es wurden zwei neuartige Elektroden mit veränderten Geometrien an den Kontaktflächen entwickelt, welche die Topologie der Bleche berücksichtigen und eine Einebnung vermeiden. Eine der Elektroden besitzt eine periodisch unterbrochene Kontaktfläche, die zweite eine laterale Profilierung mit in Schweißrichtung nichtlinearer Form der Kontaktfläche. Das Verhalten beim Schweißen wurde durch Schweißversuche bestimmt. Es wurden Schweißbereichsdiagramme bzw. Prozessfenster abgeleitet. Die Verbindungseigenschaften wurden durch Metallografie-, Festigkeits-, Druck- und Dichtheitsuntersuchungen validiert. Als Vergleich und Referenz dienen Schweißuntersuchungen mit konventionellen Rollennahtelektroden. Die geschweißten Bleche haben Wabenstrukturen als regelmäßig angeordnete Versteifungselemente mit unterschiedlichen Elementtiefen. Diese Bleche finden vorrangig Anwendung im Fahrzeugbau, in der Investitionsgüterindustrie und im Bauwesen. Aufgrund dieser Branchen und für zukünftige Anwendungen im Wärmetauscher- und Behälterbau sowie zur Ermittlung grundlegender Kenntnisse wurden die Untersuchungen an Werkstoffqualitäten DC04 und 1.4301 mit Blechdicken von 0,5 mm und 0,7 mm durchgeführt. Die Untersuchungsergebnisse zeigen Unterschiede bei den Prozessparametern und der Ausprägung der Verbindung in Abhängigkeit von der geschweißten Struktur, dem ausgewählten Schweißpfad und des geschweißten Werkstoffes gegenüber den Referenzschweißungen. Eine anschließende Optimierung führte zu einer vergleichbar guten Schweißnahtqualität sowohl bei Erhalt der Versteifungselemente mit den neuen Elektroden als auch bei deren Einebnung mit konventionellen Elektroden in Referenz zu Schweißuntersuchungen am ebenen Blech. KW - Rollennahtschweißen KW - Leichtbauelement KW - durchströmbar KW - neuartig KW - Elektrodengeometrie KW - strukturiert Y1 - 2015 SN - 978-3-945023-46-4 SP - 185 EP - 190 PB - DVS Media CY - Düsseldorf ER - TY - GEN A1 - González-Castaño, Miriam A1 - Baena-Moreno, Francisco Manuel A1 - Navarro de Miguel, Juan Carlos A1 - Miah, Kamal Uddin Mohammad A1 - Arroyo-Torralvo, Fátima A1 - Ossenbrink, Ralf A1 - Odriozola, José Antonio A1 - Benzinger, Walther A1 - Hensel, Andreas A1 - Wenka, Achim A1 - Arellano-García, Harvey T1 - 3D-printed structured catalysts for CO2 methanation reaction: Advancing of gyroid-based geometries T2 - Energy Conversion and Management N2 - This work investigates the CO2 methanation rate of structured catalysts by tuning the geometry of 3D-printed metal Fluid Guiding Elements (FGEs) structures based on periodically variable pseudo-gyroid geometries. The enhanced performance showed by the structured catalytic systems is mostly associated with the capability of the FGEs substrate geometries for efficient heat usages. Thus, variations on the channels diameter resulted in ca. 25% greater CO2 conversions values at intermediate temperature ranges. The highest void fraction evidenced in the best performing catalyst (3D-1) favored the radial heat transfer and resulted in significantly enhanced catalytic activity, achieving close to equilibrium (75%) conversions at 400 ◦C and 120 mL/min. For the 3D-1 catalyst, a mathematical model based on an experimental design was developed thus enabling the estimation of its behavior as a function of temperature, spatial velocity, hydrogen to carbon dioxide (H2/CO2) ratio, and inlet CO2 concentration. Its optimal operating conditions were established under 3 different scenarios: 1) no restrictions, 2) minimum H2:CO2 ratios, and 3) minimum temperatures and H2/CO2 ratio. For instance, for the lattest scenario, the best CO2 methanation conditions require operating at 431 ◦C, 200 mL/min, H2/CO2 = 3 M ratio, and inlet CO2 concentration = 10 %. KW - 3D-printing KW - Triply periodic minimal surfaces KW - Fluid guiding elements KW - CO2 methanation KW - Structured catalysts KW - Experiment design Y1 - 2022 U6 - https://doi.org/10.1016/j.enconman.2022.115464 SN - 2590-1745 VL - 258 ER - TY - GEN A1 - Morozova, Iuliia A1 - Bonnel, Jean-Marie A1 - Rosert, Reinhard A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Einfluss der Schweißposition beim MSG-Fülldrahtschweißen auf die Kerbschlagzähigkeit von hoch- und niedriglegierten Stählen T2 - DVS Congress 2019Große Schweißtechnische Tagung : DVS-Studentenkongress : Vorträge der Veranstaltungen in Düsseldorf vom 16. bis 17. September 2019 N2 - Die Schweißposition beeinflusst erheblich die mechanischen Eigenschaften der Schweißnaht, insbesondere die Kerbschlagzähigkeit. Dies zeigt ein umfassender Vergleich der mechanischen Eigenschaften von Schweißgütern, die in der Steigposition (PF) und Wannenlage (PA) ausgeführt wurden. Schweißgüter von Kohlenstoff-Mangan-Stählen weisen in der PF-Position eine reduzierte Kerbschlagarbeit im Vergleich zur PA-Position auf. Dagegen ist bei austenitischen und Duplexstählen der Einfluss der Schweißposition auf die Kerbschlagarbeit genau entgegengesetzt. Der Vortrag fasst den Einfluss der Schweißpositionen auf die mechanischen Eigenschaften zusammen und liefert eine Erklärung für die gegensätzlichen Auswirkungen auf die Kerbschlagzähigkeit der Schweißgüter. Der Schwerpunkt liegt dabei auf hochlegierten Fülldrähten mit einer schnell erstarrenden Schlacke. Die Schlackeneigenschaften, Schweißgutmikrostruktur, Delta-Ferrit-Gehalte für Schweißgüter vom Typ Duplexstahl (2209) und von austenitischen Schweißgütern (308L) sowie die Auswirkungen der Schweißposition auf die Richtung des Schweißkornwachstums werden erläutert. Zum Vergleich werden Kohlenstoff-Mangan-Rutil-Fülldrähte mit schnell erstarrender Schlacke herangezogen. Y1 - 2019 UR - https://www.gbv.de/dms/tib-ub-hannover/1067034390.pdf SN - 978-3-96144-066-5 SP - 310 EP - 318 PB - DVS Media GmbH CY - Düsseldorf ER - TY - PAT A1 - Kloshek, Alexander A1 - Michailov, Vesselin T1 - Schweißeinrichtung, Verfahren zur Herstellung eines Bauteils mittels Schweißung und Verwendung einer Elektrode aus Schweißzusatzwerkstoff N2 - Schweißeinrichtung (1) zum Schweißen von Werkstücken (100), umfassend eine Laserstrahlquelle (10) zur Emission eines Laserstrahls (11), eine Vorschubeinrichtung zur Realisierung einer Vorschubbewegung einer abzuschmelzenden Elektrode (70) aus Schweißzusatzwerkstoff (30) in einer Transportrichtung (21) in eine Abschmelzzone, und eine Stromkontakteinheit (60) zur Anlegung einer elektrischen Spannung an die abzuschmelzende Elektrode (70), wobei die Laserstrahlquelle (10), die Vorschubeinrichtung und die Stromkontakteinheit (60) derart relativ zueinander angeordnet und ausgebildet sind, dass die Längsachse des von der Laserstrahlquelle (10) aussendbaren Laserstrahls (11) im Wesentlichen parallel zur Transportrichtung (21) der Elektrode (70) verläuft, dadurch gekennzeichnet, dass sie eine Elektrodenformungseinrichtung (40) aufweist, mit der ein Querschnitt der Elektrode (70) erzeugbar ist, der den von der Laserstrahlquelle (10) aussendbaren Laserstrahl (11) zumindest in einem Winkelbereich von 180° umgibt. Y1 - 2016 UR - https://depatisnet.dpma.de/DepatisNet/depatisnet?action=pdf&docid=DE102014104936B4 ER - TY - CHAP A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin A1 - Wohlfahrt, Helmut T1 - Numerische Simulation der Eigenspannungen und des Bauteilverzugs beim Schweißen unter Berücksichtigung der zeitlichen und örtlichen Änderung der Dehnrate T2 - Internationale FEM-Technologietage, 20th CAD-FEM Users' Meeting, 9-11 Oktober 2002, Friedrichshafen KW - Dehngeschwindigkeit KW - Dehngrenze KW - Eigenspannung KW - Laserstrahlschweißen KW - numerische Simulation KW - Verzug Y1 - 2002 N1 - Beitrag 2.8.4 PB - CAD-FEM GmbH CY - Grafing bei München ER - TY - CHAP A1 - Kuke, Felix A1 - Kloshek, Alexander A1 - Michailov, Vesselin T1 - Untersuchung des Einflusses von rohrförmigen Stahlelektroden auf das Prozessverhalten und den Werkstoffübergang beim MSG-Schweißen T2 - DVS Congress, September 2015, Nürnberg Y1 - 2015 SN - 978-3-945023-46-4 SP - 615 EP - 620 PB - DVS Media GmbH CY - Düsseldorf ER - TY - BOOK A1 - Michailov, Vesselin A1 - Doynov, Nikolay A1 - Kuke, Felix T1 - Anwendungsnahe Simulation des thermischen Richtens : Forschungsvorhaben P 1008/IGF-Nr. 17970 BR Y1 - 2016 SN - 978-3-946885-03-0 PB - Verlag und Vertriebsgesellschaft mbH CY - Düsseldorf ER - TY - CHAP A1 - Doynov, Nikolay A1 - Kuke, Felix A1 - Michailov, Vesselin T1 - Thermal straightening simulation of welded structures T2 - Proceedings, METEC & 2nd ESTAD 2015, European Steel Technology and Application Days, Düsseldorf, Germany, CCD Congress Center Düsseldorf, 15 - 19 June 2015 Y1 - 2015 SN - 978-3-00-049542-7 SP - P 709, 1 EP - 6 PB - TEMA Technologie Marketing AG CY - Aachen ER - TY - CHAP A1 - Fritzsche, Sebastian A1 - Kloshek, Alexander A1 - Dietz, Eric A1 - Michailov, Vesselin A1 - Seidlitz, Holger A1 - Ossenbrink, Ralf T1 - SLM gefertigte Verbindungsknoten für Leichtbaurahmenelemente T2 - DVS Congress 2018 : Große Schweißtechnische Tagung, DVS-Studentenkongress, Vorträge der Veranstaltungen in Friedrichshafen am 17. und 18. September 2018 N2 - SLM gefertigte Verbindungsknoten für Leichtbaurahmenelemente KW - Selective Laser Melting KW - SLM KW - Leichtbau KW - 1.4404 KW - Topologieoptimierung KW - Schubfeld Y1 - 2018 SN - 978-3-96144-036-8 IS - 264 EP - 258 PB - DVS Media GmbH CY - Düsseldorf ER - TY - GEN A1 - Shapovalov, Oleg A1 - Ost, Lucas A1 - Kuke, Felix A1 - Doynov, Nikolay A1 - Ambrosio, Marcello A1 - Seidlitz, Holger A1 - Michailov, Vesselin T1 - Entwicklung und Analyse einer Fügestrategie für FKV/Metall-Mischverbindungen auf Basis der CMT-Pinschweißtechnik T2 - Joining Plastics N2 - Dieser Beitrag stellt eine Entwicklung, Anpassung und Untersuchung der neuartigen Pinschweißtechnik zur Verbindung thermoplastischer Faserkunststoffverbunde mit metallischen Fügepartnern dar. Die untersuchte Fügetechnik bietet, im Vergleich zu anderen Verfahren, neben einer einseitigen Zugänglichkeit, ein hohes Leichtbaupotenzial. An Multimaterial-Einzelpinverbindungen wurden die CMT-Pinschweißbarkeit charakterisiert und unterschiedliche Fügestrategien erprobt und ausgewertet. Als Bewertungskriterien wurden das Schweißgut sowie der Faser- und Matrixerhalt in Abhängigkeit von den Schweißparametern untersucht. Die mechanische Beanspruchbarkeit der mit dem entwickelten Verfahren erstellten Verbindungen wurde in Scherzugversuchen ermittelt. An Mehrpinverbindungen wurde anschließend der Einfluss der Pinanordnung untersucht und die Auslegung der Fügezone analysiert. Der Fügeprozess wurde an Funktionsmustern und diese wiederum in 3-Punkt-Biegeversuchen validiert sowie mit dem Kleben verglichen. Y1 - 2023 UR - https://www.joining-plastics.info/artikel/entwicklung-und-analyse-einer-fuegestrategie-fuer-fkvmetall-mischverbindungen-auf-basis-der-cmt-pinschweisstechnik SN - 1864-3450 VL - 17 IS - 1 SP - 28 EP - 35 ER - TY - GEN A1 - Seidlitz, Holger A1 - Michailov, Vesselin A1 - Ost, Lucas A1 - Kuke, Felix A1 - Ambrosio, Marcello A1 - Shapovalov, Oleg A1 - Doynov, Nikolay T1 - Simulation of Composites’ Heating T2 - Kunststoffe international N2 - Modern material-compatible joining methods for fiber-reinforced plastics require the heating of the materials. In order to predict the respective complex temperature fields and curves, the Fraunhofer IAP and the BTU Cottbus-Senftenberg have developed numerical methods, which are able to simulate different radiation sources and process sequences as well. KW - Composites KW - Simulation KW - Joining of Fiber-Reinforced Plastic Composites Y1 - 2023 UR - https://epaper.kunststoffe.de/en/read/26/26/2023-05-26/1 SN - 1862-4243 VL - 113 IS - 4 SP - 60 EP - 64 ER - TY - CHAP A1 - Fritzsche, Sebastian A1 - Seidlitz, Holger A1 - Winkelmann, Kai A1 - Michailov, Vesselin ED - Pająk, Anna T1 - Structural reinforced FRP sandwich constructions for lightweight floor panels T2 - Conference papers, APT '15, 11th International Conference Advances in Plastics Technology, Sosnowiec, 13 - 15 October 2015 Y1 - 2015 SN - 978-83-63555-47-4 CY - Gliwice ER - TY - PAT A1 - Schleuß, Leander A1 - Seidlitz, Holger A1 - Michailov, Vesselin T1 - Neue Fügetechnologie für Mischverbindungen Y1 - 2017 UR - https://depatisnet.dpma.de/DepatisNet/depatisnet?action=pdf&docid=DE102015118058A1 N1 - Offenlegungsschrift ER - TY - GEN A1 - Wasilewski, Eric A1 - Doynov, Nikolay A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Investigations on the thermal conditions during laser beam welding of high-strength steel 100Cr6 T2 - Advances in Industrial and Manufacturing Engineering N2 - This study examines the thermal conditions during laser beam welding of 100Cr6 high-strength steel using a TruDisk5000 disc laser with a continuous adjustable power range of 100–5000 W. Two parameter sets, characterized by laser power and welding speeds, were analyzed by thermal-metallurgical FE simulations to determine their impact on the thermal conditions during welding. The results show a significant shift in heat coupling, with conduction transitioning to deep penetration welding. As a result of the high welding speeds and reduced energy input, extremely high heating rates up to 2∙104 K s−1 (set A) respectively 4∙105 K s−1 (set B) occur. Both welds thus concern a range of temperature state values for which conventional Time-Temperature-Austenitization (TTA) diagrams are currently not defined, requiring calibration of the material models through general assumptions. Also, the change in energy input and welding speed causes significantly steep temperature gradients with a slope of approximately 5∙103 K mm−1 and strong drops in the temperature rates, particularly in the heat affected zone. The temperature cycles also show very different cooling rates for the respective parameter sets, although in both cases they are well below a cooling time t8/5 of 1 s, so that the phase transformation always leads to the formation of martensite. Since the investigated parameters are known to cause a loss of technological strength and conditionally result in cold cracks, these results will be used for further detailed experimental and numerical investigation of microstructure, hydrogen distribution, and stress-strain development at different restraint conditions. KW - laser beam welding KW - welding temperature field KW - temperature rates KW - thermal-metallurgical FE simulation KW - high-strength steel Y1 - 2023 UR - https://www.sciencedirect.com/science/article/pii/S2666912923000077 U6 - https://doi.org/10.1016/j.aime.2023.100118 SN - 2666-9129 VL - 6 ER - TY - GEN A1 - Meeß, Joachim A1 - Anasenzl, Manuel A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Influence of Particle Velocities on Adhesion Strength of Cold Spray Inner Diameter Coatings T2 - Journal of Thermal Spray Technology N2 - Due to the recent developments of hardware components and the hereby resulting ability to increase process parameters, the application area of the cold gas spray technology is expanding quickly. The present research focuses on the influence of working gas pressure and working gas temperature on the adhesive strength of inner diameter coatings, which were produced with two different alloy steel powder variants. Gas pressure and gas temperature were varied in four different parameter sets. At first, the powder variants were examined for morphology and particle size distribution. Secondly, the influence of four different process parameters on the achievable particle velocity was measured. In addition, the arithmetical mean height (Sa) of the coating was measured in order to determine the effect of the four parameter sets on the achievable surface roughness. Furthermore, the impact of the process parameters on the steel particles’ penetration depth into the aluminum substrate was examined. Finally, adhesion strength measurements of the inner diameter coatings were carried out. The results reveal that with rising process parameters, the particle velocity increases, and the achievable surface roughness is lowered. It was also shown that the penetration depth of the particles into the substrate increases with increasing particle velocity. In addition, this study demonstrated a dependence of the process parameters on the adhesion strength for inner diameter coatings. KW - adhesion strength KW - cold gas spraying (cgs) KW - cylinder block application KW - inner diameter coating KW - particle velocity Y1 - 2022 U6 - https://doi.org/10.1007/s11666-022-01439-4 SN - 1544-1016 VL - 31 IS - 7 SP - 2025 EP - 2038 ER - TY - GEN A1 - Evdokimov, Anton A1 - Jasiewicz, Filip A1 - Doynov, Nikolay A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Simulation of surface heat treatment with inclined laser beam T2 - Journal of Manufacturing Processes N2 - The beam inclination leads to a change in the laser spot size on the material surface. The higher the inclination, the larger the irradiated area and the lower the laser intensity. Moreover, if the material surface is outside of the beam focal plane, the intensity distribution profile becomes asymmetric. In this study, a heat source model, which calculates the intensity distribution on the workpiece surface as a function of beam parameters (beam waist, divergence half-angle) and process parameters (laser power, incidence angle, and distance to focal plane) was developed. The applicability of the heat source model was demonstrated by simulating 4 different laser hardening regimes. Once the heat efficiency coefficient had been calibrated the developed finite-element model allowed computation of temperatures while hardening with perpendicular laser beams as well as with inclined beams. The open-source software FEniCSx was used for the finite element computations. The mathematical formulation, required for performing temperature simulations with FEniCSx was briefly introduced. Y1 - 2022 U6 - https://doi.org/10.1016/j.jmapro.2022.06.051 SN - 1526-6125 VL - 81 SP - 107 EP - 114 ER - TY - GEN A1 - Meeß, Joachim A1 - Anasenzl, Manuel A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin A1 - Singh, Reeti A1 - Kondas, Jan T1 - Cold Gas Spray Inner Diameter Coatings and Their Properties T2 - Journal of Thermal Spray Technology N2 - Due to recent developments, cold gas spraying technology can now be used to create inner diameter coatings for cylinder inner diameters > 70 mm. The present investigations focus on the process optimization and the specific properties of cold gas spray inner diameter coatings created with three different alloy steel powder variants. The cold gas spray coating properties were compared with the corresponding properties of coatings created with twin wire arc technology. The particle velocities and deposition efficiencies were measured with the aim of optimizing the process parameters. The most suitable process parameters were used to analyze the microstructure of the deposited coating in terms of porosity and interface quality. Furthermore, the hardness and adhesion strength properties of the coatings were measured. In addition, the different liners were honed, and the achievable surface roughness of each was determined. Finally, wear resistance was evaluated using ball-on-disk testing. The results reveal that with the maximum process parameters, the cold gas spray coating properties are comparable to the twin wire arc coating properties. Further investigations are necessary to determine whether cold gas spraying is a feasible alternative to the current series production process for cylinder surface coatings. KW - automotive KW - cold gas spraying (CGS) KW - cylinder block application KW - inner diameter coating KW - wear resistance Y1 - 2022 U6 - https://doi.org/10.1007/s11666-022-01365-5 SN - 1544-1016 VL - 31 SP - 1712 EP - 1724 ER - TY - BOOK A1 - Michailov, Vesselin A1 - Stapelfeld, Christoph T1 - Erweiterung eines analytisch-numerischen Hybridmodells für die Verzugssimulation von Großstrukturen Y1 - 2014 SN - 978-3-942541-35-0 PB - Verlag und Vertriebsgesellschaft mbH CY - Düsseldorf ER - TY - RPRT A1 - Schleuß, Leander A1 - Brobeck, Andreas F. W. A1 - Ossenbrink, Ralf A1 - Polzin, Ralf A1 - Michailov, Vesselin T1 - Rollennahtschweißen strukturierter Feinbleche N2 - Strukturierte Bleche besitzen eine dreidimensionale Struktur aus regelmäßig angeordneten Versteifungselementen, welche die Steifigkeit der Bleche global erhöhen. Neben der Steifigkeitserhöhung besitzen strukturierte Bleche eine vergrößerte Oberfläche, ein verändertes akustisches Verhalten sowie ein ansprechendes Design als positive Merkmale. Mit der Qualifizierung des Rollennahtschweißens für verzugsarme, mediendichte Schweißnähte erschließen sich neue wichtige industrielle Anwendungen für strukturierte Bleche und den daraus hergestellten mehrschaligen Bauelementen (zwei strukturierte Bleche im Parallelstoß) mit Hohlräumen zwischen den Blechen. Innovative Produktentwicklungen in der Wärmetechnik, im Transportwesen und im Bauwesen können mit strukturierten Blechen für Rekuperatoren, Lüftungsanlagen, Wärmeboxen, chemische Apparate, temperierbare Behälter sowie Fußbodenheizungen, Kühlräume, Klimakammern, Fassadenelemente oder Lärmschutzwände umgesetzt werden. Derzeit steht dazu kein geeignetes Fügeverfahren zur Verfügung, welches alle Anforderungen erfüllt. Das Rollennahtschweißen eignet sich, strukturierte Bleche so zu fügen, dass sie den Anforderungen der zukünftigen Einsatzbereiche entsprechen unter Erhalt der positiven Eigenschaften. In diesem Projekt wurden strukturierte Einzelbleche und der aus ihnen gefertigten mehrschaligen Bauelemente mit dem Rollennahtschweißen gefügt. Zur Herstellung der mehrschaligen Bauelemente wurden Rollpunktnähte genutzt, welche strukturerhaltend hergestellt wurden. Dazu sind neuartige Rollennahtelektroden entwickelt, gefertigt und erprobt worden. Die notwendigen Schweißparameter zum strukturerhaltenden Schweißen und zum Schweißen mit Verformung der Struktur wurden in schweißbereichsdiagrammen dokumentiert und die Verbindungseigenschaften durch Zugversuche und Metallografie qualifiziert. Für die genannten Anwendungsbereiche wurden Dichtnähte an den Randbereichen der Bleche hergestellt. Durch die Überprüfung der Dichtheit, der Druck- und Korrosionsbeständigkeit wurden die mehrschaligen Bauelemente für mögliche Anwender qualifiziert. Für die durchgeführten Recherchen und Untersuchungen wurde ein wissenschaftlicher Mitarbeiter in Vollzeit beschäftigt und durch eine studentische Hilfskraft, sowie einen Techniker unterstützt. Die geleistete Arbeit entspricht im vollen Umfang dem begutachteten und bewilligten Antrag und war für die Durchführung des Vorhabens notwendig und angemessen. KW - Rollennahtschweißen KW - strukturiert KW - neuartig KW - Elektrodengeometrie KW - Leichtbauelement KW - mehrschalig KW - durchströmbar KW - Kühlmedien Y1 - 2015 PB - BTU, Lehrstuhl Füge- und Schweißtechnik CY - Cottbus-Senftenberg ER - TY - GEN A1 - Wasilewski, Eric ED - Gluschkowa, Diana Borysiwna ED - Dosschetschkina, Iryna Wasyliwna ED - Lalasarowa, Natalija Oleksijiwna T1 - Force Control Strategies to reduce Weld Distortion and Cold Cracking in Laser Beam Welding T2 - International Conference of Students and Young Scientists: "Modern Materials and Their Processing Technologies" N2 - In recent years, lightweight construction and the demand for resource and energy efficiency have increasingly supported the use of high-strength steels. Laser beam welding (LBW) of these materials is used in industrial mass production to efficiently manufacture high-precise components and parts with the highest quality requirements. Avoiding welding-related defects such as weld distortion and cold cracking is critical. Conventional applications currently meet this requirement to a limited extent due to very restricted process tolerances and the use of non-critical materials, which limits the potential of the joining process. Based on FE welding process simulations, concepts have been developed to reduce distortion and cracking through active control of the LBW process. The underlying models consider the weld induced temperature field, microstructure transformations, and residual stresses to calculate distortion. In addition, the local hydrogen concentration is calculated, and the results of the welding process simulation are evaluated using a cold cracking tool that includes material-specific cracking criteria. The ability to simulate distortion and cold cracking behavior opens up the possibility of parameter variation. From the data collected, concepts of active force introduction with dynamic workpiece clamping have been derived that lead to distortion and cold cracking reduction and promote the weldability of high-strength materials. KW - laser beam welding KW - high-strength steel KW - cold-cracking KW - finite element welding simulations Y1 - 2023 UR - https://www.researchgate.net/publication/370944206 SP - 6 EP - 16 CY - Charkow, Ukraine ER - TY - CHAP A1 - Dreibati, Ossama A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Hydrogen charging of high strength steel specimens and physical simulation of cold cracking under laser beam welding conditions T2 - THERMEC 2011, International Conference on Processing & Manufacturing of Advanced Materials, processing, fabrication, properties, applications, August 1 - 5, 2011, Quebec City, Canada, Vol. 2 Y1 - 2012 SN - 978-3-0-3785-303-0 SP - 1391 EP - 1396 PB - TTP, Trans Tech Publ. CY - Durnten-Zurich [u.a.] ER - TY - CHAP A1 - Sasse, Ina A1 - Schleuß, Leander A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Cutting of structured sheet metals with high power fiber laser T2 - Proceedings of International Conference on Innovative Technologies, IN-TECH, 01.09.2011 to 03.09.2011, Bratislava, Slovakia Y1 - 2011 SP - 485 EP - 488 ER - TY - CHAP A1 - Dreibati, Ossama A1 - Ossenbrink, Ralf A1 - Doynov, Nikolay A1 - Michailov, Vesselin T1 - Physical and numerical simulation of thermo-mechanical properties in the weld heat affected zone of an AlMgSi-alloy T2 - THERMEC 2011, International Conference on Processing & Manufacturing of Advanced Materials, processing, fabrication, properties, applications, August 1 - 5, 2011, Quebec City, Canada, Vol. 2 Y1 - 2011 SP - 1491 EP - 1496 PB - TTP, Trans Tech Publ. CY - Durnten-Zurich [u.a.] ER - TY - CHAP A1 - Dreibati, Ossama A1 - Zhang, Wei A1 - Wolf, Matthias A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Thermo-mechanical properties of refractory ceramic for the numerical simulation of their thermo-shock behaviour Y1 - 2011 ER - TY - CHAP A1 - Kornienko, Elena A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Investigation of corrosion behaviour of structured sheet metals by salt spray test T2 - Proceedings of International Conference on Innovative Technologies, IN-TECH, 01.09.2011 to 03.09.2011, Bratislava, Slovakia Y1 - 2011 SP - 308 EP - 311 ER - TY - CHAP A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Schweißtechnische FE-Simultaion mit Gefügeumwandlungen Y1 - 2004 N1 - CD-ROM-Ausg. ER - TY - GEN A1 - Ginzburg, Svetlana A1 - Morozova, Iuliia A1 - Kloshek, Alexander A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin A1 - Bobrynina, Elizaveta A1 - Koltsova, Tatiana S. A1 - Tolochko, Oleg V. A1 - Koçak, Mustafa A1 - Ozbek, Sunullah A1 - Morozova, Iuliia T1 - Addition of nanoparticles to flux cored wires for the nucleation of acicular ferrite microstructure in weld metals of the high-strength low-alloy steel T2 - Welding and Cutting N2 - For the reliability of many welded structures like pipelines or offshore wind parks, it is necessary to ensure high mechanical properties such as strength and toughness of the entire material. In order to improve quality of weld joints, flux cored rods and wires containing different nanoparticles (ZrO2, LaB6 and Al2O3) were manufactured and welded with the TIG and MAG welding processes. Influence of these nanoparticles on the microstructure and mechanical properties of the weld joints were investigated. The acicular ferrite and improved strength of the weld metals were observed by the addition of 0.2 wt.% of iron powder with ZrO2 nanoparticles to the filling of flux cored wires. Y1 - 2020 SN - 1612-3433 VL - 19 IS - 1 SP - 48 EP - 53 ER - TY - GEN A1 - Naumov, Anton A1 - Morozova, Iuliia A1 - Isupov, Fedor A1 - Golubev, Iurii A1 - Michailov, Vesselin T1 - Temperature Influence on Microstructure and Properties Evolution of Friction Stir Welded Al-Mg-Si Alloy T2 - Key Engineering Materials N2 - The temperature influence on the microstructure evolution and microhardness of the agehardenable aluminium alloy 6082 T6 during friction stir welding was defined. In order to achieve this aim, the thermocycles calculated using the developed 3D Finite Element Model were physically simulated on the Gleeble-3800 in the points which located in the different zones of the weld. The microstructure in the chosen points after Gleeble testing was investigated as well as the microhardness was measured. The results were consequently compared with the relevant results obtained after friction stir welding. It was shown that the microstructure and microhardness profile are influenced not only by temperature but by deformation. The increase in hardness in different zones after FSW compared to Gleeble testing can be explained by the grain refinement in the nugget zone as well as the hardening precipitate distribution along the weld which can occur more rapidly due to the deformation influence. Y1 - 2019 U6 - https://doi.org/10.4028/www.scientific.net/KEM.822.122 SN - 1662-9795 VL - 822 SP - 122 EP - 128 ER - TY - GEN A1 - Naumov, Anton A1 - Isupov, Fedor A1 - Golubev, Iurii A1 - Morozova, Iuliia T1 - Effect of the temperature of friction stir welding on the microstructure and mechanical properties of welded joints of an Al-Cu-Mg alloy T2 - Metal Science and Heat Treatment N2 - Amethod for assessing the effect of the temperature of friction stir welding on the microstructure and mechanical properties of welded joints of aluminum alloy D16AT is suggested. The temperature cycles in different zones of a welded joint are determined by mathematical simulation. The computed temperature cycles are implemented in a Gleeble-3800 system. It is shown that the welding temperature affects little the evolution of the microstructure in different zones of the welded joints of alloy D16AT. Y1 - 2019 U6 - https://doi.org/10.1007/s11041-019-00342-0 SN - 1573-8973 SN - 0026-0673 VL - 60 SP - 695 EP - 700 ER - TY - CHAP A1 - Schwenk, C. A1 - Rethmeier, M. A1 - Dilger, Klaus A1 - Michailov, Vesselin ED - Cerjak, Horst-Hannes T1 - Sensitivity Analysis of Welding Simulation Depending on Material Properties Value Variation T2 - Mathematical modelling of weld phenomena 8 KW - sensitivity analysis KW - analysis KW - welding simulation KW - simulation KW - material properties value variation KW - welding KW - schweißen KW - fügen KW - Fügetechnik Y1 - 2007 SN - 978-3-902465-69-6 PB - Verl. der Techn. Univ. Graz CY - Graz ER - TY - CHAP A1 - Doynov, Nikolay A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Verbesserte Verzugsvorhersage beim Laserstrahlschweißen durch Implementierung eines Prozessmodells T2 - Schweißen und Schneiden 2006, Vorträge der gleichnamigen Großen Schweißtechnischen Tagung in Aachen vom 20. bis 22. September 2006 KW - Verzug KW - Verzugsvorhersage KW - Laserstrahlschweißen KW - Prozessmodell KW - Modell KW - schweißen KW - fügen KW - Fügetechnik Y1 - 2006 SN - 978-3-87155-699-9 PB - DVS-Verl. CY - Düsseldorf ER - TY - CHAP A1 - Karkhin, Victor A. A1 - Homich, P. N. A1 - Michailov, Vesselin T1 - Analytical-Experimental Technique for Calculating the Temperature Fields in Laser Welding T2 - 11th Nolamp Conference in Laser Processing of Materials, August 20-22, 2007 Lappeenranta KW - analytical experimental technique KW - analytical KW - calculating temperature fields KW - temperature fields KW - laser welding KW - welding KW - Laserschweißen KW - Temperaturfelder KW - Berechnung Temperaturfelder KW - schweißen KW - fügen KW - Fügetechnik Y1 - 2007 SP - 21 EP - 27 ER - TY - CHAP A1 - Doynov, Nikolay A1 - Ossenbrink, Ralf A1 - Schmidt, J. A1 - Michailov, Vesselin T1 - Utilization of Weld Pool Models in Thermal-Mechanical Simulations T2 - Mathematical modelling of weld phenomena 8 KW - weld pool models KW - model KW - thermal-mechanical simulation KW - simulation KW - welding KW - fügen KW - schweißen KW - Fügetechnik Y1 - 2007 SN - 978-3-902465-69-6 PB - Verl. der Techn. Univ. Graz CY - Graz ER - TY - CHAP A1 - Kloshek, Alexander A1 - Michailov, Vesselin T1 - HybridPlus Hochleistungsschweißen KW - Hybridschweißen KW - Hybrid KW - Hochleistungsschweißen KW - schweißen KW - fügen KW - Fügetechnik Y1 - 2009 ER - TY - CHAP A1 - Ossenbrink, Ralf A1 - Doynov, Nikolay A1 - Michailov, Vesselin T1 - FE-Simulation des Schweißens KW - FE-Simulation KW - Simulation KW - schweißen KW - fügen Y1 - 2006 ER - TY - GEN A1 - Shapovalov, Oleg A1 - Kodzhaspirov, Georgii A1 - Hantelmann, Cord A1 - Michailov, Vesselin T1 - Effect of a Welding Method on the Fatigue Strength and Fracture of Foam–Aluminum Sandwiches T2 - Russian Metallurgy (Metally) N2 - The influence of argon-arc welding and laser welding on the fatigue properties and the fracture of a foam–aluminum sandwich is studied. Argon-arc-welded samples are found to have the highest fatigue strength. KW - aluminum sandwich KW - fatigue strength KW - four-point bending KW - butt weld Y1 - 2019 UR - https://link.springer.com/journal/11505/2019/10/page/2 U6 - https://doi.org/10.1134/S0036029519100239 SN - 0036-0295 VL - Vol. 2019 IS - 10 SP - 1063 EP - 1066 ER - TY - CHAP A1 - Kloshek, Alexander A1 - Pietsch, N. T1 - Trennen und Fügen dicker Bleche KW - Trennen KW - Fügen KW - dicke Bleche KW - Bleche KW - schweißen KW - Fügetechnik Y1 - 2009 ER - TY - CHAP A1 - Doynov, Nikolay A1 - Ossenbrink, Ralf A1 - Kloshek, Alexander A1 - Michailov, Vesselin T1 - Simulation of the Welding Distortions in Large Welded Structures KW - Simulation KW - Welding Distortions KW - Distortions KW - Welded Structures KW - welding KW - schweißen KW - fügen KW - Simulation KW - Fügetechnik Y1 - 2007 UR - http://www.fabtechexpo.com ER - TY - CHAP A1 - Nauroschat, C. A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Ermittlung von lokalen Bauteileigenschaften durch physikalische Simulation des Schweißens T2 - Fortschritte in der Metallographie, Vortragstexte der 42. Metallographie-Tagung, 17. - 19. September 2008 in Jena KW - Bauteileigenschaften KW - physikalische Simulation KW - Simulation KW - schweißen KW - Fügetechnik Y1 - 2008 SN - 3-88355-370-0 SP - 227 EP - 232 PB - MAT-INFO CY - Frankfurt am Main [u.a.] ER - TY - CHAP A1 - Stark, O. A1 - Kloshek, Alexander A1 - Doynov, Nikolay A1 - Michailov, Vesselin T1 - FE-Prozesssimulation des Unterpulverschweißens T2 - Die Verbindungs-Spezialisten 2008, Vorträge und Posterbeiträge der Veranstaltung in Dresden vom 17. bis 19. September 2008 KW - FE-Prozesssimulation KW - Simulation KW - Unterpulverschweißen KW - UP KW - schweißen KW - fügen KW - Fügetechnik Y1 - 2008 SN - 978-3-87155-256-4 SP - 490 EP - 493 PB - DVS-Verl. CY - Düsseldorf ER - TY - CHAP A1 - Stapelfeld, Christoph A1 - Doynov, Nikolay A1 - Michailov, Vesselin T1 - Das Maximaltemperaturmodell und das gekoppelt analytisch-numerische Schrumpfkraftmodell angewandt an einer komplexen Struktur KW - Maximaltemperaturmodell KW - temperaturmodell KW - Maximaltemperatur KW - modell KW - schrumpfkraftmodell KW - analytisch numerische Schrumpfkraftmodell KW - komplexe struktur KW - struktur Y1 - 2009 ER - TY - CHAP A1 - Deflorio, Andrea A1 - Klingler, M. A1 - Brinkmann, D. A1 - Michailov, Vesselin ED - Cerjak, Horst-Hannes T1 - Laser Beam Welding Simulation with two Different Approaches T2 - Mathematical modelling of weld phenomena 8 KW - Laser Beam Welding KW - Simulation KW - Different Approaches KW - Laserstrahlschweißen KW - welding KW - schweißen KW - fügen KW - Fügetechnik Y1 - 2007 SN - 978-3-902465-69-6 PB - Verl. der Techn. Univ. Graz CY - Graz ER - TY - CHAP A1 - Stapelfeld, Christoph A1 - Doynov, Nikolay A1 - Michailov, Vesselin T1 - Hybride Berechnungsansätze zur Prognostizierung und Minimierung des Verzugs komplexer Schweißkonstruktionen T2 - SYSWELD Forum, 22.-23. Oktober 2009, Tagungsband KW - Hybride Berechnungsansätze KW - Berechnung KW - Verzug KW - komplexe Schweißkonstruktion KW - Schweißkonstruktion KW - schweißen KW - fügen KW - Fügetechnik Y1 - 2009 SN - 978-3-86068-401-6 SP - 91 EP - 105 PB - Univ.-Verl. CY - Weimar ER - TY - CHAP A1 - Fritzsche, Sebastian T1 - Flexible Weiterverarbeitung strukturierter Bleche KW - Weiterverarbeitung KW - strukturierte Bleche KW - struckturiert KW - Bleche Y1 - 2008 ER - TY - CHAP A1 - Stapelfeld, Christoph A1 - Doynov, Nikolay A1 - Michailov, Vesselin T1 - Neue Lösungsansätze zur Schweißverzugsberechnung T2 - 20. Symposium Simulationstechnik, ASIM 2009, Brandenburgische Technische Universität 23. - 25. September 2009 Y1 - 2009 SN - 978-3-9811800-5-3 SP - 155 EP - 159 PB - Brandenburgische Techn. Univ. CY - Cottbus ER - TY - CHAP A1 - Fritzsche, Sebastian T1 - Geklebte Verbundbauteile - Bewertung der Festigkeit KW - geklebte Verbundbauteile KW - kleben KW - Verbundbauteile KW - Bauteile KW - geklebte Bauteile KW - Bewertung KW - Festigkeit Y1 - 2008 ER - TY - CHAP A1 - Stapelfeld, Christoph A1 - Kloshek, Alexander A1 - Doynov, Nikolay A1 - Michailov, Vesselin T1 - Analytisches Schrumpfkraftmodell und Berechnungsprogramm zur Bestimmung des schweißbedingten Verzugs T2 - Die Verbindungs-Spezialisten 2008, Vorträge und Posterbeiträge der Veranstaltung in Dresden vom 17. bis 19. September 2008 KW - analytisches Schrumpfkraftmodell KW - Schrumpfkraftmodell KW - Schrumpfkraft KW - Modell KW - Berechnung KW - Berechnungsprogramm KW - schweißen KW - schweißbedingter Verzug KW - Verzug KW - Schweißverzug Y1 - 2008 SN - 978-3-87155-256-4 SP - 401 EP - 405 PB - DVS-Verl. CY - Düsseldorf ER - TY - CHAP A1 - Pfennig, T. A1 - Kloshek, Alexander A1 - Ossenbrink, Ralf A1 - Doynov, Nikolay A1 - Michailov, Vesselin T1 - Experimentelle und numerische Untersuchungen von Al-Stahl-Mischverbindungen T2 - Die Verbindungs-Spezialisten 2009, Vorträge der Veranstaltung in Essen vom 14. bis 19. September 2009 KW - experimentell KW - numerisch KW - Untersuchung KW - Mischverbindung KW - Verbindung KW - Al KW - Stahl KW - schweißen KW - fügen KW - Fügetechnik Y1 - 2009 SN - 978-3-87155-584-8 SP - 236 EP - 240 ER - TY - CHAP A1 - Genchev, Gancho Vladimirov A1 - Doynov, Nikolay A1 - Michailov, Vesselin T1 - Sensibilitätsanalyse der thermomechanischen Schweißsimulation - Bewertung des Vernetzungseinflusses T2 - Die Verbindungs-Spezialisten 2008, Vorträge und Posterbeiträge der Veranstaltung in Dresden vom 17. bis 19. September 2008 KW - Sensibilitätsanalyse KW - Analyse KW - thermomechanische Schweißsimulation KW - thermomechanisch KW - Schweißsimulation KW - Simulation KW - Vernetzungseinfluss KW - schweißen KW - fügen KW - Fügetechnik Y1 - 2008 SN - 978-3-87155-256-4 SP - 494 EP - 497 PB - DVS-Verl. CY - Düsseldorf ER - TY - RPRT A1 - Dilger, Klaus A1 - Michailov, Vesselin T1 - Schlussbericht zum BMBF-Verbundprojekt SST-Schweißsimulationstool - Werkzeug zur vollständigen numerischen Simulation des Schmelzschweißens KW - BMBF Verbundprojekt KW - SST-Schweißsimulationstool KW - Schweißsimulationstool KW - Forschungsbericht KW - Schweißsimulation KW - numerische Simulation KW - Schmelzschweißen KW - schweißen KW - fügen KW - Fügetechnik Y1 - 2006 SN - 978-3-8322-5414-8 PB - Shaker-Verl. CY - Aachen ER - TY - GEN A1 - Karkhin, Victor A. A1 - Homich, P. N. A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Experimentellgestütztes Berechnungsverfahren zur Ermittlung des Temperaturfeldes beim Laserstrahlschweißen T2 - Zeitschrift "Schweißproduktion" KW - experimentellgestütztes Berechnungsverfahren KW - experimentelles Berechnungsverfahren KW - Berechnungsverfahren KW - Temperaturfeld KW - Laserstrahlschweißen KW - schweißen KW - fügen KW - Fügetechnik Y1 - 2006 N1 - russiche Ausg. SP - 13 EP - 17 ER - TY - CHAP A1 - Michailov, Vesselin A1 - Doynov, Nikolay A1 - Pfennig, T. A1 - Degen, M. A1 - Ossenbrink, Ralf T1 - Simulationsgestützte Entwicklung einer Aluminium-Stahl-Schweißkontruktion eines Slicermessers für die Lebensmittelverarbeitung T2 - Große Schweißtechnische Tagung 2011 Y1 - 2011 SN - 978-3-87155-267-0 SP - 428 EP - 433 PB - DVS Media GmbH CY - Düsseldorf ER - TY - GEN A1 - Ivanov, Sergey Y. A1 - Karkhin, Victor A. A1 - Michailov, Vesselin A1 - Martikainen, J. A1 - Hiltunen, E. T1 - Assessment of the Sensitivity of Welded Joints of Al –Mg – Si Alloys to Liquation Cracks Under Laser Welding T2 - Metal Science and Heat Treatment N2 - The microstructure and the distribution of chemical elements in laser-welded joints of Al – Mg – Si alloy 6005-T6 are studied. Segregations of chemical elements are detected over grain boundaries in the heat-affected zones of the welded joints. The joints fracture by the intergrain mechanism. A Gleeble 3800 device is used to determine the temperature dependences of the mechanical properties of the alloy with allowance for the special features of the welding cycle. Amethod for evaluating the sensitivity of welded joints of aluminum alloys to formation of liquation cracks with allowance for the local properties of the metal, the welding conditions, and the rigidity of the construction is suggested. KW - laser welding KW - Al – Mg – Si alloy KW - microstructure KW - microscopic chemical analysis KW - liquation cracks KW - stress-strain state Y1 - 2018 U6 - https://doi.org/10.1007/s11041-018-0225-2 SN - 0026-0673 VL - Vol. 59 IS - 11-12 SP - 773 EP - 778 ER - TY - GEN A1 - Bobrynina, E. V. A1 - Larionova, T. V. A1 - Koltsova, Tatiana S. A1 - Ginzburg, S. A. A1 - Michailov, Vesselin T1 - Effect of alumina addition on weld deposits microstructure at the welding of carbon steel T2 - Materials Physics and Mechanics N2 - The formation of acicular ferrite in the structure of weld deposits when welding carbon steels is often associated with the introduction of nonmetallic additives into the electrode material. Fe–alumina composite powders with alumina particles less than 1 µm were used as a filler for cored welding wire and the influence of aluminum oxide additives up to 2,5 wt.% on the structure of the welded seam was studied. It was shown that the addition of aluminum oxide to the welding wire led to the initiation of the formation of intragranular acicular ferrite in the weld deposit and to a more even distribution of hardness through the zones of weld seam. KW - acicular ferrite KW - alumina KW - welding KW - carbon steel Y1 - 2018 U6 - https://doi.org/10.18720/MPM.3812018_4 SN - 1605-8119 VL - Vol. 38 IS - 1 SP - 26 EP - 32 ER - TY - GEN A1 - Bokuchava, Gizo A1 - Petrov, Peter A1 - Genchev, Gancho Vladimirov A1 - Michailov, Vesselin A1 - Doynov, Nikolay A1 - Ossenbrink, Ralf T1 - Residual stress analysis in welded joints by neutron difffraction and comouter modeling T2 - Romanian Journal of Physics N2 - Numerical models for thermo-mechanical simulation of the welding residual stresses in laser beam and multi-pass arc welded joints are developed. The models describe the resulting microstructure as a function of the peak temperature, austenization time, cooling time and take into account the microstructure formed after single or multiple thermal cycles. The results of simulations are validated by neutron diffraction experiments performed on FSD diffractometer at the IBR-2 pulsed reactor in FLNP JINR (Dubna, Russia). The elaborated numerical models are in good agreement with obtained neutron diffraction data, which enable to study the influence of different conditions and process parameters on the distribution of residual welding stresses. KW - residual stress KW - neutron diffraction KW - computer modeling KW - welding Y1 - 2018 SN - 1221-146X VL - Vol. 63 IS - 7-8 ER - TY - GEN A1 - Zhang, Wei A1 - Evdokimov, Anton A1 - Schleuß, Leander A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Laser beam build-up welding of AlSi12-powder on AlSi1MgMn-alloy substrate T2 - Progress in Additive Manufacturing N2 - In the present work, laser beam build-up welding of AlSi12 alloy powder on AlSi1MgMn-alloy (EN AW-6082) substrate has been studied to determine the laser deposition strategy for fabrication of 3-D structure. First, the influence of laser power, scanning speed and powder feeding rate on the output parameters, such as clad geometry, dilution ratio, powder efficiency and porosity were analysed for deposition of a single track. Mathematical relationships were then established and the optimal parameters were identified by the desirability approach. Second, these optimal process parameters are furthermore adjusted to fabricate rectangular, cylindrical and complex combination volumes; different layer deposition strategies are used and evaluated. Finally, by using an adapted deposition strategy, one prototype consisted of different complexly shaped elements on one curved Al-alloy substrate without welding fusion defects was manufactured. The average tensile strength of deposited samples with four different layer deposition directions (vertical 0°/90°; horizontal 0°/90°; horizontal 0° and horizontal 90°) was measured, respectively, which are comparable strengths or higher than those of cast samples. The microstructure of the laser-deposited material is investigated using optical microscopy and scanning electron microscopy as well as microcomputed tomography. Microstructure and hardness of deposited multilayers exhibit inhomogeneous distributions, which vary with the deposit location KW - Laser beam build-up welding KW - Laser metal deposition KW - AlSi12 KW - Additive manufacturing KW - Build-up strategy Y1 - 2019 UR - https://doi.org/10.1007/s40964-018-0065-z SN - 2363-9512 VL - 4 IS - 2 SP - 117 EP - 129 ER - TY - GEN A1 - Golubev, Iurii A1 - Morozova, Iuliia A1 - Naumov, Anton A1 - Hantelmann, Cord A1 - Doynov, Nikolay A1 - Michailov, Vesselin T1 - Numerical Simulation and Experimental Investigation on Impulse Friction Stir Welding of 6082-T6 Aluminum Alloy T2 - Papers from Materials Science and Technology 2017 (MS&T17), October 8 – 12, 2017, David L. Lawrence Convention Center, Pittsburgh, Pennsylvania USA N2 - The series of impulse friction stir welding (IFSW) experiments for aluminum alloy 6082-T6 butt joints was performed to obtain micrographs, tensile and hardness test samples and to receive the validation data for a numerical model of the process. Impulse force and frequency were varied to determine the effect of individual process parameters on microstructure evolution and mechanical properties of the welded butt joints. A three-dimensional model was established to simulate temperature distribution, heat generation and contact state between the tool and the workpiece during IFSW. Based on the numerical simulation, the influence of the impulses on heat input, maximum weld temperatures and contact state was found. The combination of impulse force and frequency effected the grain refinement. The influence of impulses on the elongation and hardness of the welded joints during IFSW were determined. Y1 - 2017 UR - https://www.researchgate.net/publication/326434324_Numerical_Simulation_and_Experimental_Investigation_on_Impulse_Friction_Stir_Welding_of_6082-T6_Aluminum_Alloy U6 - https://doi.org/10.7449/2017/mst_2017_987_994 SP - 987 EP - 994 ER - TY - CHAP A1 - Doynov, Nikolay A1 - Christov, St. A1 - Michailov, Vesselin T1 - Development of the Strains during Local Explosive Post Treatment of Welded Joints T2 - Mathematical modelling of weld phenomena 7, papers presented at the Seventh International Seminar 'Numerical Analysis of Weldability' held 2003 at Schloss Seggau near Graz, Austria Y1 - 2005 SN - 3-901351-99-X SP - 363 EP - 375 PB - Techn. Univ. CY - Graz ER - TY - GEN A1 - Michailov, Vesselin T1 - Advanced Analytical-Numerical Approach for Simulation of Welding Distortions T2 - Journal of Materials Science and Technology Y1 - 2007 SN - 0861-9786 VL - 15 IS - 3 SP - 139 EP - 150 ER - TY - GEN A1 - Sasse, Ina A1 - Schleuß, Leander A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Joining of structured sheet metals - Remote laser beam welding in comparison with resistance spot welding T2 - Welding and Cutting N2 - One main problem of thin-walled, large-area sheet components for lightweight construction solutions is the inadequate stiffness. One approach for a solution is provided by structured sheet metals which have an increased flexural stiffness due to three-dimensionally incorporated structures. The areas of application of the structured sheet metals (e.g. in subassemblies in automobile, rail vehicle and tank construction) necessitate adapted welding technologies. Since few systematic investigations have been conducted on structured sheet metals in the field of joining technology until now, there is a lack of knowledge about the further processing of these sheets by means of welding technology. The aims of the presented investigations are to make it possible to utilise these modern semi-finished products industrially using remote laser beam welding and to compare this with resistance spot welding. Both are important joining processes in the areas of applications interesting for structured sheet metals and thus constitute key technologies for industrial utilisation. Resistance spot welding has already been qualified for utilisation on structured sheet metals [1]. In addition, investigations were conducted into the remote laser beam welding of structured and flat sheets. These investigations encompass the possibilities of joining structured and flat joining members by means of remote laser beam welding as well as the assessment of the joint strength in tensile shear and peel tests. Thereafter, the results of the investigations are compared with the resistance spot welding of structured sheet metals and specific application recommendations are derived. KW - structured metals sheet KW - Remote laser beam welding KW - resistance spot welding Y1 - 2014 VL - 13 IS - 1 SP - 43 EP - 47 ER - TY - GEN A1 - Hantelmann, Cord A1 - Fritzsche, Sebastian A1 - Michailov, Vesselin A1 - Boywitt, Ralf A1 - Risse, Steffen A1 - Paulinus, Dietmar T1 - Utilisation of aluminium foam sandwich components in welded structures T2 - Welding and Cutting Y1 - 2016 SN - 1612-3433 IS - 5 SP - 317 EP - 325 ER - TY - GEN A1 - Ivanov, Sergey Y. A1 - Karkhin, Victor A. A1 - Michailov, Vesselin A1 - Martikainen, J. A1 - Hiltunen, E. T1 - Modellierung der Entstehung von Heißrissen beim Laserschweißen von Al-Mg-Si-Legierungen T1 - Моделирование образования ликвационных трещин при лазерной сварке Al-Mg-Siсплаво T2 - Izvestija Tul'skogo Gosudarstvennogo Universiteta T2 - Nachrichten der staatlichen Universität Tula Y1 - 2015 SN - 2071-6168 VL - 6 IS - 2 SP - 66 EP - 74 ER - TY - GEN A1 - Ivanov, Sergey Y. A1 - Karkhin, Victor A. A1 - Michailov, Vesselin T1 - Modellierung thermodynamischer Prozesse beim Schweißen von ungeraden Nähten T1 - Моделирование тепловых процессов при сварке соединений с криволинейными швами T2 - Izvestija Tul'skogo Gosudarstvennogo Universiteta T2 - Nachrichten der staatlichen Universität Tula Y1 - 2015 SN - 2071-6168 VL - 6 IS - 2 SP - 62 EP - 66 ER - TY - GEN A1 - Isupov, Fedor A1 - Ganin, Sergey A1 - Tcemenko, Valeriy A1 - Michailov, Vesselin T1 - Numerical simulation of sheet profiling process from aluminum alloy T2 - METAL 2015, 24th International Conference on Metallurgy and Materials, Brno, Czech Republic, June 3rd-5th, 2015, Conference proceedings Y1 - 2015 SN - 978-80-87294-62-8 SP - 1463 EP - 1468 PB - Tanger CY - Ostrava ER - TY - JOUR A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin A1 - Wohlfahrt, Helmut T1 - Numerical simulation of welding stresses and distortions under consideration of temporal and local changes of strain rate Y1 - 2004 ER - TY - GEN ED - Michailov, Vesselin ED - Ossenbrink, Ralf ED - Doynov, Nikolay T1 - Internationales Symposium Schweißtechnik - Verfahren, Werkstoffe, Simulation : 6. November 2013 T1 - International Symposium Welding Technology - Processes, Materials, Simulation : 6. November 2013 KW - Schweißsimulation; Schweißtechnik;Schweißverfahren Y1 - 2013 SN - 978-3-8440-2319-0 PB - Shaker CY - Aachen ER - TY - BOOK A1 - Michailov, Vesselin A1 - Karkhin, Victor A. A1 - Petrov, Peter T1 - Principles of welding Y1 - 2016 SN - 978-5-7422-5569-7 PB - Polytechnic Univ. Publ. CY - St. Petersburg ER - TY - BOOK A1 - Michailov, Vesselin A1 - Karkhin, Victor A. A1 - Petrov, Peter T1 - Grundlagen der Schweißtechnik KW - Schweißverfahren KW - Physik des Schweißens KW - Temperaturfelder beim Schweißen KW - Metallurgie des Schweißens KW - Schweißverzüge und -eigenspannungen Y1 - 2012 SN - 978-954-90912-6-7 PB - Bauwesen CY - Sofia ER - TY - THES A1 - Dreibati, Ossama T1 - Physical welding simulation of the cold crack susceptibility KW - Cold Crack; hydrogen embrittlement; Cold crack criterion; High strength steel Y1 - 2014 SN - 978-3-8440-3133-1 PB - Shaker CY - Aachen ER - TY - THES A1 - Deflorio, Andrea T1 - Distortion Simulation of Cylindrical Body Shape during Laser Beam Welding KW - Laser beam welding KW - welding simulation KW - residual stresses KW - distortions KW - simulation tool KW - material models Y1 - 2008 SN - 978-3-8322-7636-2 PB - Shaker CY - Aachen ER - TY - GEN A1 - Genchev, Gancho Vladimirov A1 - Doynov, Nikolay A1 - Ossenbrink, Ralf A1 - Bokuchava, Gizo A1 - Petrov, Peter A1 - Michailov, Vesselin T1 - Numerical and Experimental Study of Residual Stress Distribution in Laser Beam Welded Joint Y1 - 2016 UR - https://www.tugraz.at/fileadmin/user_upload/Events/Seggau/Dokumente/Dokumente_THERMEC/Program_Book_April_2016.pdf N1 - THERMEC 2016, 9th International Conference on Processing & Manufacturing of Advanced Materials, May 29-June 03, 2016, Graz, Austria SP - S. 20 ER - TY - GEN A1 - Shapovalov, Oleg A1 - Seidlitz, Holger A1 - Ost, Lucas A1 - Doynov, Nikolay A1 - Kuke, Felix A1 - Ambrosio, Marcello A1 - Michailov, Vesselin T1 - Substitution von metallischen Schubfeldern im Fahrzeugbau durch fügetechnische Integration von FKV-Schalen T2 - DVS Congress 2022, Große Schweißtechnische Tagung, DVS Campus ; Kurzfassungen der Vorträge der Veranstaltung in Koblenz vom 19. bis 21. September 2022 ; (Langfassungen der Beiträge auf USB-Karte) N2 - Durch den strukturellen Einsatz von Faser-Kunststoff-Verbunden (FKV) lassen sich hochwertige gewichtsoptimierte Karosserien in Mischbauweise umsetzen. Die untersuchte CMT-Pin-Schweißtechnik zur Verbindung von thermoplastischen Organoblechen mit Stählen bietet, im Vergleich zu anderen Verfahren, neben einer einseitigen Zugänglichkeit, ein hohes Leichtbaupotenzial. Das Vorhaben wurde auf eine werkstoff-, prozess- und konstruktionsgerechte Umsetzung des Verfahrens ausgerichtet. Auf Basis experimenteller und numerischer Untersuchungen wurde eine Methode zum Vorwärmen von Organoblechen mittels Infrarotstrahlung entwickelt. Die Eignung der CMT-Pin-Technologie wurde sowohl für das Fügen von karbon- als auch glasfaserverstärktem PA6 betrachtet. Als Bewertungskriterien wurden das Schweißgut sowie der Faser- und Matrixerhalt in Abhängigkeit der Schweißparameter untersucht. Das entwickelte Verfahren wurde mit herkömmlichen Fügemethoden bzgl. der in Kopf- und Scherzugversuchen ermittelten Festigkeiten verglichen. Zur Bestimmung der Beständigkeit der Verbindungen gegen unterschiedliche Witterungsbedingungen wurden Salzsprühnebel- und Wechselkorrosionstests durchgeführt. Mit dem Fügen von Hutprofilen wurde die Anwendung der entwickelte CMT-Pin-Technik am Tunnel sowie den Längs- und Querträgern der Bodenstruktur eines Kraftfahrzeugs demonstriert. Y1 - 2022 UR - https://www.dvs-ev.de/call4papers/abstract.cfm?vid=115&pid=7586 SN - 978-3-96144-189-1 SP - 385 EP - 393 PB - DVS Media GmbH CY - Düsseldorf ER - TY - GEN A1 - Seidlitz, Holger A1 - Ost, Lucas A1 - Ambrosio, Marcello A1 - Kuke, Felix A1 - Michailov, Vesselin A1 - Shapovalov, Oleg A1 - Doynov, Nikolay T1 - Erwärmung von Composites simulieren T2 - Kunststoffe N2 - Neuartige, werkstoffgerechte Fügeverfahren für Faserkunststoffverbunde setzen die Erwärmung der Materialien voraus. Um die damit verbundenen komplexen Temperaturfelder und -verläufe vorherzusagen, haben das Fraunhofer IAP und die BTU Cottbus-Senftenberg numerische Verfahren entwickelt. Mit diesen können auch verschiedene Strahlungsquellen und Prozessabläufe simuliert werden. KW - Faserkunststoffverbunde KW - Fügen KW - Simulation Y1 - 2023 UR - https://www.kunststoffe.de/a/article-3363044 SN - 0023-5563 IS - 2 SP - 66 EP - 70 ER - TY - CHAP A1 - Schleuß, Leander A1 - Seidlitz, Holger A1 - Fritzsche, Sebastian A1 - Schulze, Marcus A1 - Michailov, Vesselin A1 - Schuhmann, Tilo T1 - Gewichtsreduzierte Multi-Material-Bauweisen mit Organoblechen T2 - Tagungsband, 15. Chemnitzer Textiltechnik-Tagung, Chemnitz, Germany, 31.05-01.06.2016 Y1 - 2016 SN - 978-3-945479-06-3 SP - 112 EP - 119 PB - Technische Universität Chemnitz, Professur Fördertechnik CY - Chemnitz ER - TY - CHAP A1 - Haase, Florian Vincent A1 - Reinhold, Maximilian A1 - Woll, Ralf A1 - Wolf, Matthias A1 - Seidlitz, Holger ED - Walls, Lesley ED - Revie, Matthew ED - Bedford, Tim T1 - Reliability capability assessment of cooperative networks using the example of developing demonstrators of structured materials T2 - Risk, Reliability and Safety: Innovating Theory and Practice, Proceedings of the ESREL 2016, Glasgow (United Kingdom) Y1 - 2016 SN - 978-1-138-02997-2 SP - 1323 EP - 1329 PB - CRC Press CY - Boca Raton ER - TY - CHAP A1 - Seidlitz, Holger A1 - Fritzsche, Sebastian A1 - Schleuß, Leander A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin T1 - Neuartige Fügetechnologie zum Herstellen von hochbelastbaren Multi-Material-Bauweisen aus textilverstärkten Kunststoffen und Metallen bei einseitiger Zugänglichkeit der Fügestelle T2 - DVS Congress 2016, Große Schweißtechnische Tagung, Vorträge der Veranstaltungen in Leipzig am 19. und 20. September 2016 Y1 - 2016 SN - 978-3-945023-74-7 SP - 424 EP - 428 PB - DVS-Verlag CY - Düsseldorf ER - TY - GEN A1 - Ivanov, Sergey Y. A1 - Karkhin, Victor A. A1 - Michailov, Vesselin A1 - Martikainen, J. A1 - Hiltunen, E. T1 - Оценка чувствительности сварных соединений Al - Mg - Si-сплавов к ликвационным трещинам при лазерной сварке T1 - Empfindlichkeitsbetrachtung von Heißrissen beim Laserschweißen von Al-Mg-Si-Legierungen T2 - Metallovedenie i termicheskaya obrabotka metallov Y1 - 2017 UR - http://mitom.folium.ru/contents/2017/2017-12.php SN - 0026-0819 IS - 12 ER - TY - GEN A1 - Kotlarski, Georgi A1 - Ormanova, Maria A1 - Nikitin, Alexander A1 - Morozova, Iuliia A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin A1 - Doynov, Nikolay A1 - Valkov, Stefan T1 - Structure Formation and Mechanical Properties of Wire Arc Additively Manufactured Al4043 (AlSi5) Components T2 - Metals N2 - In the current paper, the correlation between the physical size of additively built wire arc specimens and their structure and properties is studied. For the purpose of this work, two oval shaped specimens of different lengths were manufactured under the same technological conditions. The specimens have a length of 200 mm and 400 mm and will be referred to as L200 and L400. The microstructure of the samples was studied using X-ray diffraction analysis (XRD), optical microscopy, and scanning electron microscopy (SEM). The microhardness, yield strength (YS), and ultimate tensile strength (UTS) were determined and their correlation with the technological conditions of specimen build-up was clarified. The results of the carried out experiments indicated that the crystallographic structure of both specimens is similar. The scanning electron microscopy images show a higher concentration of irregularly shaped micro-pores formed near the edge of the αAl grains in the structure of the L400 specimen compared to the L200 one. An increase in the size of the αAl solid solution grains in the case of the L200 specimen towards its top section was noticed using optical microscopy. A slightly lower magnitude change was noticed concerning the L400 specimen. The increase in the size of the aluminum crystals was determined to be the increasing interpass temperature. Due to the much smaller thermal dissipation capacity of the smaller specimen, the interpass temperature of the same increased faster compared to the larger specimen. All of the above-mentioned factors led to a decrease in the microhardness of the specimens at higher stages of build-up. Since the specimens were deposited using similar layer deposition conditions, the resultant YS and UTS data are also highly comparable. KW - structure KW - morphology KW - hardness KW - tensile strength KW - defects formation KW - WAAM KW - AlSi5 KW - Al4043 KW - GMAW KW - cold arc pulse Y1 - 2024 U6 - https://doi.org/10.3390/met14020183 SN - 2075-4701 VL - 14 IS - 2 ER - TY - GEN A1 - Kotlarski, Georgi A1 - Ormanova, Maria A1 - Nikitin, Alexander A1 - Morozova, Iuliia A1 - Ossenbrink, Ralf A1 - Michailov, Vesselin A1 - Doynov, Nikolay A1 - Valkov, Stefan T1 - Microstructural and Mechanical Properties of CAP-WAAM Single-Track Al5356 Specimens of Differing Scale T2 - Materials N2 - The mass production of metallic components requires high agility in the working process conditioned by the necessity of building details of different shapes and sizes. Changing the size of the components theoretically influences the thermal dissipation capability of the same, which could lead to a change in their structure and mechanical properties. This is particularly important when aluminum alloys are concerned. For this reason, two Al5356 single-track specimens were built using the same technological conditions of layer deposition by varying only their geometrical size. In all cases, the specimens were wire and arc additively manufactured (WAAM) using a process based on gas metal arc welding (GMAW) in the cold arc pulse mode (CAP). The structure of both specimens was studied and defects along their surfaces were detected in the form of micro-pores and micro-cracks. A high concentration of undissolved Mg particles was also detected, along with some standalone Si particles. Uniformity in the build-up process was achieved, which led to the formation of nearly identical structures in the specimens. Subsequently, the resultant mechanical properties were also highly comparable. This indicates that the geometry-related variation in thermal conditions has an insignificant influence on the component’s structure and properties. KW - microstructure KW - WAAM KW - cold arc pulse (CAP) KW - AlMg5Cr KW - Al5356 KW - single-track KW - mechanical properties Y1 - 2024 U6 - https://doi.org/10.3390/machines12010072 SN - 2075-1702 VL - 12 IS - 1 ER - TY - GEN A1 - Kotlarski, Georgi A1 - Ormanova, Maria A1 - Ossenbrink, Ralf A1 - Nikitin, Alexander A1 - Doynov, Nikolay A1 - Valkov, Stefan A1 - Michailov, Vesselin T1 - Fabrication and Characterization of Wire Arc Additively Manufactured AlSi5 Structures T2 - Metals N2 - For the purpose of this research, single track details were manufactured in the shape of thin walls with a length of 100 mm and a height of 80 mm. Two welding speeds were chosen for this experiment–13.3 mm/s and 20.0 mm/s corresponding to the following heat inputs: 120 J/mm and 80 J/mm. The gas metal arc welding (GMAW) method was used for the build-up of the specimens in the cold arc pulse mode. The structure of the specimens was studied using X-ray diffraction (XRD) analysis carried out with CuKα radiation with a wavelength of 1.5406 Ǻ, optical microscopy, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX). Furthermore, the Vickers hardness of the samples was determined using a ZwickRoell DuraScan 10/20 G5 unit at a force of 1 N. A preferred crystallographic orientation towards the (200) plane was observed in all cases, however a vastly textured structure was observed with inclusions of peaks in the (111), (220), and (311) crystallographic planes. The full width at half maximum (FWHM) of samples taken from different stages of build-up was calculated indicating an increase of the dislocation density at the more advanced stages of specimen growth. Despite that an increase of the hardness was observed towards the top of both specimens. This is attributed to the change in the structure of the αAl + Si formations from an irregular one at the bottom of the specimens, towards a fibrous one at the top. The results are discussed in regard to the optimization of the build-up process during wire arc additive manufacturing (WAAM). KW - wire arc additive manufacturing KW - Al4043 KW - AlSi5 KW - heat input KW - microstructure KW - eutectic formations Y1 - 2022 SN - 2075-4701 VL - 12 IS - 11 ER -