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