@inproceedings{DoynovChristovMichailov, author = {Doynov, Nikolay and Christov, St. and Michailov, Vesselin}, title = {Development of the Strains during Local Explosive Post Treatment of Welded Joints}, series = {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}, booktitle = {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}, publisher = {Techn. Univ.}, address = {Graz}, isbn = {3-901351-99-X}, pages = {363 -- 375}, language = {en} } @inproceedings{StapelfeldDoynovMichailov, author = {Stapelfeld, Christoph and Doynov, Nikolay and Michailov, Vesselin}, title = {Das Maximaltemperaturmodell und das gekoppelt analytisch-numerische Schrumpfkraftmodell angewandt an einer komplexen Struktur}, language = {de} } @inproceedings{StapelfeldKloshekDoynovetal., author = {Stapelfeld, Christoph and Kloshek, Alexander and Doynov, Nikolay and Michailov, Vesselin}, title = {Analytisches Schrumpfkraftmodell und Berechnungsprogramm zur Bestimmung des schweißbedingten Verzugs}, series = {Die Verbindungs-Spezialisten 2008, Vortr{\"a}ge und Posterbeitr{\"a}ge der Veranstaltung in Dresden vom 17. bis 19. September 2008}, booktitle = {Die Verbindungs-Spezialisten 2008, Vortr{\"a}ge und Posterbeitr{\"a}ge der Veranstaltung in Dresden vom 17. bis 19. September 2008}, publisher = {DVS-Verl.}, address = {D{\"u}sseldorf}, isbn = {978-3-87155-256-4}, pages = {401 -- 405}, language = {de} } @inproceedings{StarkKloshekDoynovetal., author = {Stark, O. and Kloshek, Alexander and Doynov, Nikolay and Michailov, Vesselin}, title = {FE-Prozesssimulation des Unterpulverschweißens}, series = {Die Verbindungs-Spezialisten 2008, Vortr{\"a}ge und Posterbeitr{\"a}ge der Veranstaltung in Dresden vom 17. bis 19. September 2008}, booktitle = {Die Verbindungs-Spezialisten 2008, Vortr{\"a}ge und Posterbeitr{\"a}ge der Veranstaltung in Dresden vom 17. bis 19. September 2008}, publisher = {DVS-Verl.}, address = {D{\"u}sseldorf}, isbn = {978-3-87155-256-4}, pages = {490 -- 493}, language = {de} } @inproceedings{GenchevDoynovMichailov, author = {Genchev, Gancho Vladimirov and Doynov, Nikolay and Michailov, Vesselin}, title = {Sensibilit{\"a}tsanalyse der thermomechanischen Schweißsimulation - Bewertung des Vernetzungseinflusses}, series = {Die Verbindungs-Spezialisten 2008, Vortr{\"a}ge und Posterbeitr{\"a}ge der Veranstaltung in Dresden vom 17. bis 19. September 2008}, booktitle = {Die Verbindungs-Spezialisten 2008, Vortr{\"a}ge und Posterbeitr{\"a}ge der Veranstaltung in Dresden vom 17. bis 19. September 2008}, publisher = {DVS-Verl.}, address = {D{\"u}sseldorf}, isbn = {978-3-87155-256-4}, pages = {494 -- 497}, language = {de} } @inproceedings{PfennigKloshekOssenbrinketal., author = {Pfennig, T. and Kloshek, Alexander and Ossenbrink, Ralf and Doynov, Nikolay and Michailov, Vesselin}, title = {Experimentelle und numerische Untersuchungen von Al-Stahl-Mischverbindungen}, series = {Die Verbindungs-Spezialisten 2009, Vortr{\"a}ge der Veranstaltung in Essen vom 14. bis 19. September 2009}, booktitle = {Die Verbindungs-Spezialisten 2009, Vortr{\"a}ge der Veranstaltung in Essen vom 14. bis 19. September 2009}, isbn = {978-3-87155-584-8}, pages = {236 -- 240}, language = {de} } @inproceedings{StapelfeldDoynovMichailov, author = {Stapelfeld, Christoph and Doynov, Nikolay and Michailov, Vesselin}, title = {Neue L{\"o}sungsans{\"a}tze zur Schweißverzugsberechnung}, series = {20. Symposium Simulationstechnik, ASIM 2009, Brandenburgische Technische Universit{\"a}t 23. - 25. September 2009}, booktitle = {20. Symposium Simulationstechnik, ASIM 2009, Brandenburgische Technische Universit{\"a}t 23. - 25. September 2009}, publisher = {Brandenburgische Techn. Univ.}, address = {Cottbus}, isbn = {978-3-9811800-5-3}, pages = {155 -- 159}, language = {de} } @inproceedings{StapelfeldDoynovMichailov, author = {Stapelfeld, Christoph and Doynov, Nikolay and Michailov, Vesselin}, title = {Hybride Berechnungsans{\"a}tze zur Prognostizierung und Minimierung des Verzugs komplexer Schweißkonstruktionen}, series = {SYSWELD Forum, 22.-23. Oktober 2009, Tagungsband}, booktitle = {SYSWELD Forum, 22.-23. Oktober 2009, Tagungsband}, publisher = {Univ.-Verl.}, address = {Weimar}, isbn = {978-3-86068-401-6}, pages = {91 -- 105}, language = {de} } @inproceedings{DoynovOssenbrinkKlosheketal., author = {Doynov, Nikolay and Ossenbrink, Ralf and Kloshek, Alexander and Michailov, Vesselin}, title = {Simulation of the Welding Distortions in Large Welded Structures}, language = {en} } @inproceedings{StadtausDoynovMichailov, author = {Stadtaus, Marc and Doynov, Nikolay and Michailov, Vesselin}, title = {Investigation of the Modified CTS-Test for the Prediction of Cold Cracking Susceptibility by Numerical Models}, series = {Mathematical modelling of weld phenomena 8}, booktitle = {Mathematical modelling of weld phenomena 8}, editor = {Cerjak, Horst-Hannes}, publisher = {Verl. der Techn. Univ. Graz}, address = {Graz}, isbn = {978-3-902465-69-6}, language = {en} } @inproceedings{DoynovOssenbrinkSchmidtetal., author = {Doynov, Nikolay and Ossenbrink, Ralf and Schmidt, J. and Michailov, Vesselin}, title = {Utilization of Weld Pool Models in Thermal-Mechanical Simulations}, series = {Mathematical modelling of weld phenomena 8}, booktitle = {Mathematical modelling of weld phenomena 8}, publisher = {Verl. der Techn. Univ. Graz}, address = {Graz}, isbn = {978-3-902465-69-6}, language = {en} } @inproceedings{OssenbrinkDoynovMichailov, author = {Ossenbrink, Ralf and Doynov, Nikolay and Michailov, Vesselin}, title = {FE-Simulation des Schweißens}, language = {de} } @inproceedings{DoynovOssenbrinkMichailov, author = {Doynov, Nikolay and Ossenbrink, Ralf and Michailov, Vesselin}, title = {Verbesserte Verzugsvorhersage beim Laserstrahlschweißen durch Implementierung eines Prozessmodells}, series = {Schweißen und Schneiden 2006, Vortr{\"a}ge der gleichnamigen Großen Schweißtechnischen Tagung in Aachen vom 20. bis 22. September 2006}, booktitle = {Schweißen und Schneiden 2006, Vortr{\"a}ge der gleichnamigen Großen Schweißtechnischen Tagung in Aachen vom 20. bis 22. September 2006}, publisher = {DVS-Verl.}, address = {D{\"u}sseldorf}, isbn = {978-3-87155-699-9}, language = {de} } @inproceedings{StapelfeldDoynovAtanasovaetal., author = {Stapelfeld, Christoph and Doynov, Nikolay and Atanasova, D. and Michailov, Vesselin}, title = {Calculation of Welding Distortions in Large Structures Using the Maximum Temperature Model and the Coupled Analytic-Numerical Shrinkage Force Model}, series = {ESI Global Forum 2010, 19. - 20. Mai 2010, M{\"u}nchen}, booktitle = {ESI Global Forum 2010, 19. - 20. Mai 2010, M{\"u}nchen}, language = {en} } @inproceedings{MichailovStapelfeldDoynov, author = {Michailov, Vesselin and Stapelfeld, Christoph and Doynov, Nikolay}, title = {Verzugsberechnung einer komplexen Struktur mittels eines analytisch-numerischen Hybridmodells}, series = {DVS Congress 2010, Große Schweißtechnische Tagung, Studentenkongress, Statusseminar "Schneidtechnik" - Abschlusskolloquium zum AiF-Forschungscluster "Integration des R{\"u}hrreibschweißens in Fertigungsprozessketten, N{\"u}rnberg 27./28. September 2010}, booktitle = {DVS Congress 2010, Große Schweißtechnische Tagung, Studentenkongress, Statusseminar "Schneidtechnik" - Abschlusskolloquium zum AiF-Forschungscluster "Integration des R{\"u}hrreibschweißens in Fertigungsprozessketten, N{\"u}rnberg 27./28. September 2010}, publisher = {DVS Media GmbH}, address = {D{\"u}sseldorf}, isbn = {978-3-87155-592-3}, pages = {128 -- 132}, language = {de} } @inproceedings{GenchevDoynovMichailov, author = {Genchev, Gancho Vladimirov and Doynov, Nikolay and Michailov, Vesselin}, title = {Kennlinien zur Festlegung der erforderlichen r{\"a}umlichen und zeitlichen Diskretisierung bei der thermomechanischen Schweißsimulation}, language = {de} } @incollection{MichailovDoynovPfennigetal., author = {Michailov, Vesselin and Doynov, Nikolay and Pfennig, T. and Degen, M. and Ossenbrink, Ralf}, title = {Simulationsgest{\"u}tzte Entwicklung einer Aluminium-Stahl-Schweißkontruktion eines Slicermessers f{\"u}r die Lebensmittelverarbeitung}, series = {Große Schweißtechnische Tagung 2011}, booktitle = {Große Schweißtechnische Tagung 2011}, publisher = {DVS Media GmbH}, address = {D{\"u}sseldorf}, isbn = {978-3-87155-267-0}, pages = {428 -- 433}, language = {de} } @incollection{MichailovKloshekDoynov, author = {Michailov, Vesselin and Kloshek, Alexander and Doynov, Nikolay}, title = {Thermomechanische Simulation geschweißter Mischverbindungen aus Aluminium- und Stahlwerkstoffen}, series = {Jahrbuch Schweißtechnik 2012}, booktitle = {Jahrbuch Schweißtechnik 2012}, publisher = {DVS Media GmbH}, address = {D{\"u}sseldorf}, isbn = {978-3-87155-606-7}, pages = {173 -- 184}, language = {de} } @misc{MichailovDoynovStapelfeldetal., author = {Michailov, Vesselin and Doynov, Nikolay and Stapelfeld, Christoph and Ossenbrink, Ralf}, title = {Hybrid Model for Prediction of Welding Distortions in Large Structures}, series = {Journal of Frontiers of Materials Science}, volume = {5}, journal = {Journal of Frontiers of Materials Science}, number = {2}, issn = {2095-025X}, pages = {209 -- 215}, language = {en} } @inproceedings{DreibatiOssenbrinkDoynovetal., author = {Dreibati, Ossama and Ossenbrink, Ralf and Doynov, Nikolay and Michailov, Vesselin}, title = {Physical and numerical simulation of thermo-mechanical properties in the weld heat affected zone of an AlMgSi-alloy}, series = {THERMEC 2011, International Conference on Processing \& Manufacturing of Advanced Materials, processing, fabrication, properties, applications, August 1 - 5, 2011, Quebec City, Canada, Vol. 2}, booktitle = {THERMEC 2011, International Conference on Processing \& Manufacturing of Advanced Materials, processing, fabrication, properties, applications, August 1 - 5, 2011, Quebec City, Canada, Vol. 2}, publisher = {TTP, Trans Tech Publ.}, address = {Durnten-Zurich [u.a.]}, pages = {1491 -- 1496}, language = {en} } @misc{DreibatiOssenbrinkDoynovetal., author = {Dreibati, Ossama and Ossenbrink, Ralf and Doynov, Nikolay and Michailov, Vesselin}, title = {Physical and numerical simulation of thermo-mechanical properties in the weld heat affected zone of an AlMgSi-alloy}, series = {Materials Science Forum}, volume = {706-709}, journal = {Materials Science Forum}, issn = {0255-5476}, pages = {1491 -- 1496}, language = {en} } @book{MichailovDoynovOssenbrink, author = {Michailov, Vesselin and Doynov, Nikolay and Ossenbrink, Ralf}, title = {Sensibilit{\"a}tsanalyse der thermomechanischen FE-Schweißsimulation}, publisher = {Shaker}, address = {Aachen}, isbn = {978-3-8440-1016-9}, pages = {137}, language = {de} } @misc{GenchevDreibatiOssenbrinketal., author = {Genchev, Gancho Vladimirov and Dreibati, Ossama and Ossenbrink, Ralf and Doynov, Nikolay and Michailov, Vesselin}, title = {Physical and Numerical Simulation of the Heat-affected Zone of Multi-pass Welds}, series = {Materials Science Forum}, journal = {Materials Science Forum}, number = {Vol. 762}, issn = {0255-5476}, pages = {544 -- 550}, abstract = {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.}, language = {en} } @incollection{GenchevOssenbrinkDoynovetal., author = {Genchev, Gancho Vladimirov and Ossenbrink, Ralf and Doynov, Nikolay and Michailov, Vesselin}, title = {Gef{\"u}geeigenschaften in der W{\"a}rmeeinflusszone von Mehrlagenschweißungen aus S355J2+N}, series = {Fortschritte in der Metallographie}, booktitle = {Fortschritte in der Metallographie}, editor = {Keßler, Olaf}, publisher = {Inventum}, address = {Bonn}, isbn = {978-3-88355-392-4}, pages = {167 -- 172}, language = {de} } @inproceedings{GenchevDoynovOssenbrinketal., author = {Genchev, Gancho Vladimirov and Doynov, Nikolay and Ossenbrink, Ralf and Michailov, Vesselin}, title = {Simulation des Mehrlagenschweißens unter Ber{\"u}cksichtigung der Gef{\"u}geumwandlungen}, series = {Conference proceedings, 2012 - ANSYS Conference \& 30. CADFEM Users' Meeting, 24. - 26. Oktober 2012, Kassel}, booktitle = {Conference proceedings, 2012 - ANSYS Conference \& 30. CADFEM Users' Meeting, 24. - 26. Oktober 2012, Kassel}, publisher = {CADFEM GmbH}, address = {Grafing}, pages = {Art. 2.2.9}, abstract = {Der Konferenzvortrag stellt das entwickelte M-STAAZ Modell vor. Mit dem M-STAAZ l{\"a}sst sich in der FE-Simulation die {\"A}nderung der Werkstoffkennwerte bei mehrmaliger Temperaturbelastung wie in der WEZ von Mehrlagenschweißungen ber{\"u}cksichtigen.}, language = {de} } @inproceedings{GenchevDoynovOssenbrinketal., author = {Genchev, Gancho Vladimirov and Doynov, Nikolay and Ossenbrink, Ralf and Michailov, Vesselin}, title = {Bewertung der relevanten Einflussfaktoren auf die Gef{\"u}geumwandlungen und thermomechanischen Eigenschaften bei komplexen Temperaturbelastungen}, series = {ANSYS Conference \& 29. CADFEM Users' Meeting 2011, conference proceedings, 19. - 21. October 2011, Stuttgart, ICS}, booktitle = {ANSYS Conference \& 29. CADFEM Users' Meeting 2011, conference proceedings, 19. - 21. October 2011, Stuttgart, ICS}, publisher = {CADFEM GmbH}, address = {Grafing}, isbn = {3-937523-08-1}, abstract = {Der Vortrag stellt die Identifizierung und Bewertung der relevanten Einflussfaktoren auf die Gef{\"u}geumwandlungen und auf die thermomechanischen Werkstoffkennwerte bei komplexen Temperaturbelastungen vor. Dies erfolgt durch physikalische Simulation der Gef{\"u}ge 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 Gef{\"u}geumwandlung identifiziert. Hinweise zu den erforderlichen Werkstoffkennwerten f{\"u}r die numerische Schweißsimulation wurden gegeben.}, language = {de} } @inproceedings{GenchevOssenbrinkDoynovetal., author = {Genchev, Gancho Vladimirov and Ossenbrink, Ralf and Doynov, Nikolay and Michailov, Vesselin}, title = {Material Properties of the HAZ of Multi-Pass Welded Joints from low alloyed Steel}, series = {Junior Euromat 2012, Paperlist}, booktitle = {Junior Euromat 2012, Paperlist}, pages = {A297}, language = {en} } @misc{ZhangDoynovWolfetal., author = {Zhang, Wei and Doynov, Nikolay and Wolf, Matthias and Dreibati, Ossama and Ossenbrink, Ralf and Michailov, Vesselin}, title = {Investigation of the Thermal Shock Behavior of Ceramic Using a Combination of Experimental Testing and FE-Simulation Methods}, series = {Advanced engineering materials}, volume = {15}, journal = {Advanced engineering materials}, number = {6}, issn = {1527-2648}, doi = {10.1002/adem.201200241}, pages = {480 -- 484}, abstract = {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.}, language = {en} } @incollection{DoynovChristovMichailovetal., author = {Doynov, Nikolay and Christov, St. and Michailov, Vesselin and Wohlfahrt, Helmut}, title = {Finite Elements Simulation of Multipass Submerged Arc Welding}, series = {Mathematical Modelling of Weld Phenomena 6}, booktitle = {Mathematical Modelling of Weld Phenomena 6}, publisher = {Maney - IOM}, address = {London}, isbn = {978-1-902653-56-3}, pages = {651 -- 669}, language = {en} } @inproceedings{OssenbrinkDoynovMichailov, author = {Ossenbrink, Ralf and Doynov, Nikolay and Michailov, Vesselin}, title = {Welding simulation of aluminium to steel joints by means of arc welding Processes}, series = {10th International Scientific and Technical Conference, Advanced metal materials and technologies (AMMT'2013), June 25-29, Saint Petersburg, 2013}, booktitle = {10th International Scientific and Technical Conference, Advanced metal materials and technologies (AMMT'2013), June 25-29, Saint Petersburg, 2013}, publisher = {Izdat. Polytechn. Univ.}, address = {Saint Petersburg, Russia}, pages = {523 -- 528}, abstract = {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.}, language = {en} } @incollection{OssenbrinkGenchevDoynov, author = {Ossenbrink, Ralf and Genchev, Gancho Vladimirov and Doynov, Nikolay}, title = {Simulation der Schweißeigenspannungen und des -verzuges unter Ber{\"u}cksichtigung der Gef{\"u}geumwandlungen mit dem STAAZ-Modell}, series = {Internationales Symposium Schweißtechnik - Verfahren, Werkstoffe, Simulation, Cottbus, 6. November 2013}, booktitle = {Internationales Symposium Schweißtechnik - Verfahren, Werkstoffe, Simulation, Cottbus, 6. November 2013}, editor = {Michailov, Vesselin}, publisher = {Shaker Verlag}, address = {Aachen}, isbn = {978-3-8440-2319-0}, pages = {149 -- 167}, abstract = {Die vorliegende Arbeit stellt das von Professor Michailov vorgeschlagene Spitzentemperatur-Austenitisierungs- Abk{\"u}hlzeit-Modell f{\"u}r die thermomechanische Schweißsimulation unter Ber{\"u}cksichtigung der Gef{\"u}geumwandlungen vor. Das Modell erfasst die f{\"u}r die Gef{\"u}geausbildung maßgebenden Temperaturzyklen durch seine drei so genannten STAAZ-Parameter: Spitzentemperatur, Austenitisierungs- und Abk{\"u}hlzeit. Die Korrelation dieser Temperaturzyklusparameter mit den thermomechanischen gef{\"u}geabh{\"a}ngigen Werkstoffeigenschaften erfolgt auf Grundlage einer empirischen Datenbasis. Mit der vorgenommenen Erweiterung zu Mehrmalig-(M-)STAAZ l{\"a}sst sich das aus einem vorgelagerten Temperaturzyklus entstandene Zwischengef{\"u}ge ber{\"u}cksichtigen.}, language = {de} } @misc{JakobsenZhangDoynovetal., author = {Jakobsen, Daniel and Zhang, Wei and Doynov, Nikolay and B{\"o}hm, Anna and Malzbender, J{\"u}rgen and Michailov, Vesselin and Roosen, Andreas}, title = {Thermal shock behaviour of laminated multilayer refractories for steel casting applications reinforced by residual stresses}, series = {Ceramics International}, volume = {42}, journal = {Ceramics International}, number = {12}, issn = {0272-8842}, doi = {10.1016/j.ceramint.2016.05.149}, pages = {13562 -- 13571}, language = {en} } @misc{ZhangDoynovOssenbrinketal., author = {Zhang, Wei and Doynov, Nikolay and Ossenbrink, Ralf and Michailov, Vesselin}, title = {Physical and FE-Simulation of Thermal Shock Behaviour of Refractory Ceramics}, series = {refractories WORLDFORUM}, volume = {8}, journal = {refractories WORLDFORUM}, number = {2}, issn = {1868-2405}, pages = {110 -- 117}, language = {en} } @inproceedings{ZhangDoynovOssenbrinketal., author = {Zhang, Wei and Doynov, Nikolay and Ossenbrink, Ralf and Michailov, Vesselin and Scheithauer, Uwe and Michaelis, Alexander}, title = {Investigation of thermal shock behaviour of refractory ceramics based on the calcium-aluminate}, series = {14th Biennial Worldwide Congress Unified International Technical Conference on Refractories (UNITECR) 2015, Vienna, Austria, September 15-18, 2015}, booktitle = {14th Biennial Worldwide Congress Unified International Technical Conference on Refractories (UNITECR) 2015, Vienna, Austria, September 15-18, 2015}, address = {Hannover}, isbn = {978-3-9815813-1-7}, language = {en} } @misc{AtangaZhangDreibatietal., author = {Atanga, Valetine Kubong and Zhang, Wei and Dreibati, Ossama and Doynov, Nikolay and Ossenbrink, Ralf and Michailov, Vesselin and Scheffler, Michael}, title = {Alumina-mullite Materials for Refractory Applications: Microstructure, Physical and Finite Element Simulation of Thermal Shock Behaviour}, series = {refractories WORLDFORUM}, volume = {4}, journal = {refractories WORLDFORUM}, number = {1}, issn = {1868-2405}, pages = {159 -- 164}, language = {en} } @misc{GenchevDoynovOssenbrinketal., author = {Genchev, Gancho Vladimirov and Doynov, Nikolay and Ossenbrink, Ralf and Michailov, Vesselin}, title = {Modelling the Local Microstructure Properties due to Multi-Pass Welding}, series = {Materials Science Forum}, volume = {Vol. 879}, journal = {Materials Science Forum}, issn = {0255-5476}, doi = {10.4028/www.scientific.net/MSF.879.595}, pages = {595 -- 600}, language = {en} } @misc{MichailovDoynov, author = {Michailov, Vesselin and Doynov, Nikolay}, title = {Analytical-Numerical Modeling Approach for Calculation of the Structural Distortions after Welding and Thermal Straightening}, series = {Journal of Mechanics Engineering and Automation}, volume = {6}, journal = {Journal of Mechanics Engineering and Automation}, number = {5}, issn = {2159-5283}, doi = {10.17265/2159-5275/2016.05.004}, pages = {246 -- 253}, language = {en} } @inproceedings{Doynov, author = {Doynov, Nikolay}, title = {Anwendungsnahe Simulation des thermischen Richtens}, series = {Schweißen in der Maritimen Technik und im Ingenieurbau, 16. Tagung, 20./21. April 2016 in Hamburg}, booktitle = {Schweißen in der Maritimen Technik und im Ingenieurbau, 16. Tagung, 20./21. April 2016 in Hamburg}, publisher = {GSI SLV Nord}, address = {Hamburg}, pages = {78 -- 88}, language = {de} } @inproceedings{GenchevDoynovOssenbrinketal., author = {Genchev, Gancho Vladimirov and Doynov, Nikolay and Ossenbrink, Ralf and Michailov, Vesselin}, title = {Schweißtechnische Simulation der lokalen Eigenschaften in der W{\"a}rmeeinflusszone von Mehrlagenschweißungen}, series = {ANSYS Conference \& 33rd CADFEM Users' Meeting, 24. - 26. Juni, Bremen, conference proceedings}, booktitle = {ANSYS Conference \& 33rd CADFEM Users' Meeting, 24. - 26. Juni, Bremen, conference proceedings}, publisher = {CADFEM GmbH}, address = {Grafing}, language = {de} } @inproceedings{DoynovKukeMichailov, author = {Doynov, Nikolay and Kuke, Felix and Michailov, Vesselin}, title = {Thermal straightening simulation of welded structures}, series = {Proceedings, METEC \& 2nd ESTAD 2015, European Steel Technology and Application Days, D{\"u}sseldorf, Germany, CCD Congress Center D{\"u}sseldorf, 15 - 19 June 2015}, booktitle = {Proceedings, METEC \& 2nd ESTAD 2015, European Steel Technology and Application Days, D{\"u}sseldorf, Germany, CCD Congress Center D{\"u}sseldorf, 15 - 19 June 2015}, publisher = {TEMA Technologie Marketing AG}, address = {Aachen}, isbn = {978-3-00-049542-7}, pages = {P 709, 1 -- 6}, language = {en} } @misc{GenchevDoynovOssenbrinketal., author = {Genchev, Gancho Vladimirov and Doynov, Nikolay and Ossenbrink, Ralf and Bokuchava, Gizo and Petrov, Peter and Michailov, Vesselin}, title = {Numerical and Experimental Study of Residual Stress Distribution in Laser Beam Welded Joint}, pages = {S. 20}, language = {en} } @inproceedings{PetrovBokuchavaPapushkinetal., author = {Petrov, Peter and Bokuchava, Gizo and Papushkin, Igor and Genchev, Gancho Vladimirov and Doynov, Nikolay and Michailov, Vesselin and Ormanova, Maria}, title = {Neutron diffraction studies of laser welding residual stresses}, series = {19th International Conference and School on Quantum Electronics: Laser Physics and Applications, 26-30 September 2016 Sozopol, Bulgaria}, booktitle = {19th International Conference and School on Quantum Electronics: Laser Physics and Applications, 26-30 September 2016 Sozopol, Bulgaria}, publisher = {SPIE}, address = {Bellingham, Wash.}, isbn = {978-1-5106-0953-2}, doi = {10.1117/12.2261802}, language = {en} } @inproceedings{KrawczynskiDoynovMichailov, author = {Krawczynski, Damian and Doynov, Nikolay and Michailov, Vesselin}, title = {Minimization of Residual Welding Stress and Distortins in Aluminium-Steel Hybrid Structure}, series = {Innowacje w procesach produkcyjnych, technologicznych i bezpieczeństwie : XXXVIII Studencka Sesja Naukowa, Częstochowa, 29 maj 2014 : praca zbiorowa}, booktitle = {Innowacje w procesach produkcyjnych, technologicznych i bezpieczeństwie : XXXVIII Studencka Sesja Naukowa, Częstochowa, 29 maj 2014 : praca zbiorowa}, publisher = {Wydawnictwo Wydziału Inżynierii Produkcji i Technologii Materiał{\´o}w Politechniki Częstochowskie}, address = {Częstochowa}, isbn = {879-83-63989-02-6}, pages = {59 -- 63}, language = {en} } @misc{GenchevDoynovOssenbrinketal., author = {Genchev, Gancho Vladimirov and Doynov, Nikolay and Ossenbrink, Ralf and Michailov, Vesselin and Bokuchava, Gizo and Petrov, Peter}, title = {Residual stresses formation in multi-pass weldment: A numerical and experimental study}, series = {Journal of Constructional Steel Research}, volume = {138}, journal = {Journal of Constructional Steel Research}, issn = {0143-974X}, doi = {10.1016/j.jcsr.2017.08.017}, pages = {633 -- 641}, abstract = {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.}, language = {en} } @misc{DoynovMichailov, author = {Doynov, Nikolay and Michailov, Vesselin}, title = {Distortion analysis of heat spot straightening thin-walled welded structures: part 2: analytical-numerical approach}, series = {International Journal of Advanced Manufacturing Technology}, volume = {95}, journal = {International Journal of Advanced Manufacturing Technology}, number = {1-4}, issn = {0268-3768}, doi = {10.1007/s00170-017-1214-0}, pages = {469 -- 478}, abstract = {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.}, language = {en} } @book{MichailovDoynovKuke, author = {Michailov, Vesselin and Doynov, Nikolay and Kuke, Felix}, title = {Anwendungsnahe Simulation des thermischen Richtens : Forschungsvorhaben P 1008/IGF-Nr. 17970 BR}, publisher = {Verlag und Vertriebsgesellschaft mbH}, address = {D{\"u}sseldorf}, isbn = {978-3-946885-03-0}, pages = {XV, 122}, language = {de} } @misc{DoynovMichailov, author = {Doynov, Nikolay and Michailov, Vesselin}, title = {Distortion analysis of heat spot straightening thin-walled welded structures: part 1: analytical-numerical approach}, series = {The International Journal of Advanced Manufacturing Technology}, volume = {94}, journal = {The International Journal of Advanced Manufacturing Technology}, number = {1-4}, issn = {0268-3768}, doi = {10.1007/s00170-017-0911-z}, pages = {667 -- 676}, abstract = {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).}, language = {en} } @incollection{GolubevDoynovHantelmannetal., author = {Golubev, Iurii and Doynov, Nikolay and Hantelmann, Cord and Michailov, Vesselin}, title = {W{\"a}rmequellemodell und FE-Temperaturfeldsimulation f{\"u}r das R{\"u}hrreibschweißen}, series = {DVS Congress 2017 : Große Schweißtechnische Tagung : DVS-Studentenkongress : Vortr{\"a}ge der Veranstaltungen in D{\"u}sseldorf vom 26. bis 29. September 2017}, booktitle = {DVS Congress 2017 : Große Schweißtechnische Tagung : DVS-Studentenkongress : Vortr{\"a}ge der Veranstaltungen in D{\"u}sseldorf vom 26. bis 29. September 2017}, publisher = {DVS Media}, address = {D{\"u}sseldorf}, isbn = {978-3-96144-008-5}, pages = {112}, language = {de} } @misc{EvdokimovSpringerDoynovetal., author = {Evdokimov, Anton and Springer, Katrin and Doynov, Nikolay and Ossenbrink, Ralf and Michailov, Vesselin}, title = {Heat source model for laser beam welding of steel-aluminum lap joints}, series = {International Journal of Advanced Manufacturing Technology}, volume = {93}, journal = {International Journal of Advanced Manufacturing Technology}, number = {1-4}, issn = {0268-3768}, doi = {10.1007/s00170-017-0569-6}, pages = {709 -- 716}, abstract = {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.}, language = {en} } @inproceedings{GolubevMorozovaNaumovetal., author = {Golubev, Iurii and Morozova, Iuliia and Naumov, Anton and Hantelmann, Cord and Doynov, Nikolay and Michailov, Vesselin}, title = {Numerical simulation and experimental investigation on Numerical simulation of 6082-T6 aluminum alloy}, series = {Materials Science and Technology 2017, (MS\&T17), Pittsburgh, Pennsylvania, USA, October 8-12, 2017, volume 2}, booktitle = {Materials Science and Technology 2017, (MS\&T17), Pittsburgh, Pennsylvania, USA, October 8-12, 2017, volume 2}, publisher = {Curran Associates, Inc.}, address = {Red Hook, NY}, isbn = {978-1-5108-5058-3}, pages = {987 -- 994}, abstract = {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.}, language = {en} }