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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 -