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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 -