Dokument-ID Dokumenttyp Autoren/innen Persönliche Herausgeber/innen Haupttitel Abstract Auflage Verlagsort Verlag Herausgeber (Institution) Erscheinungsjahr Titel des übergeordneten Werkes Jahrgang/Band ISBN Veranstaltung Veranstaltungsort Beginndatum der Veranstaltung Enddatum der Veranstaltung Ausgabe/Heft Erste Seite Letzte Seite URN DOI Lizenz Datum der Freischaltung OPUS4-132 Dissertation Schwenk, Christopher FE-Simulation des Schweißverzugs laserstrahlgeschweißter dünner Bleche Sensitivitätsanalyse durch Variation der Werkstoffkennwerte Der Hauptaspekt der vorliegenden Dissertation ist die Sensitivitätsanalyse der FE- Schweißsimulation, basierend auf einer Variation der Werkstoffkennwerte, sowie deren Einfluss auf das transiente Temperaturfeld und die Verzüge. Dabei wird das Streuband der Werkstoffkennwerte für den gesamten Temperaturbereich sowie für diskrete Temperaturintervalle, die aus der Metallurgie und den experimentellen Randbedingungen abgeleitet sind, betrachtet. Die Untersuchung findet an drei verschiedenen Legierungen statt, welche zurzeit gebräuchliche Werkstoffe im Automobilbau innerhalb der folgenden Hauptlegierungsgruppen darstellen: • hochfester Dualphasenstahl • austenitischer Chrom-Nickel-Stahl • aushärtbare Aluminiumlegierung Die betrachteten Kennwerte sind Wärmeleitfähigkeit, spezifische Wärmekapazität und Dichte sowie E-Modul, Dehngrenze, thermische Dehnung, Querkontraktionszahl und Verfestigungsverhalten. Die Untersuchungen zeigen den großen Einfluss der spezifischen Wärmekapazität und der Dichte auf das berechnete Temperaturfeld und die anschließend ermittelten Verzüge. Mit Blick auf die thermomechanischen Kennwerte werden die Verzüge hauptsächlich von der thermischen Dehnung, dem E-Modul und der Dehngrenze beeinflusst. Die wichtigen thermophysikalischen und thermomechanischen Kennwerte werden für alle drei Legierungen gemessen. Diese sehr genauen Daten werden für eine Simulation ohne die möglichen Fehlerquellen der Streuung der Werkstoffkennwerte verwendet. Die Daten der Werkstoffkennwerte werden dann entsprechend der bekannten Streubänder variiert um die Sensitivität der simulierten Temperaturzyklen und Verzüge zu ermitteln. Die Berechnungsergebnisse werden über Schweißversuche an ebenen Platten mit Laserstrahl- Blindnähten validiert (Thermoelementmessungen, Nahtquerschliffe und Wegaufnehmermessungen der Verzüge). Darüber hinaus werden die Ergebnisse anhand einer Schweißsimulation und Verzugsoptimierung eines industriell relevanten Bauteils überprüft. Die Ergebnisse, Meinungen und Schlüsse dieser Dissertation sind nicht notwendigerweise die der Volkswagen AG. Berlin Bundesanstalt für Materialforschung und -prüfung (BAM) 2007 26 978-3-9811655-5-5 1 185 urn:nbn:de:kobv:b43-1324 http://www.gesetze-im-internet.de/urhg/index.html 2015-01-23 OPUS4-25623 Zeitschriftenartikel Brauser, Stephan; Schwenk, Christopher; Rethmeier, Michael; Noack, T.; Jüttner, S. Einfluss von schweißbedingten Rissen auf die Schwingfestigkeit von Widerstandspunktschweißverbindungen aus hochfestem austenitischen Stahl Unter den rauen Bedingungen in der Automobilkarosseriefertigung lassen sich schweißbedingte Imperfektionen wie Risse beim Widerstandspunktschweißen von hochfesten Stählen nicht immer vermeiden. Dabei ist der Einfluss solcher Risse auf die Schwingfestigkeit insbesondere von modernen hochfesten austenitischen Stählen derzeit nicht hinreichend bekannt. Im Rahmen dieser Arbeit wurde daher der Einfluss von Schweißrissen verschiedener Lage und Ausbildung untersucht. Dabei konnte durch die Analyse der normierten Steifigkeitsverläufe von Proben sowie durch die Gegenüberstellung der Versagensschwingspielzahlen nachgewiesen werden, dass die spritzerfrei erzeugten Oberflächenrisse im Zentrum, im Übergangsbereich sowie im Randbereich der Schweißlinse keinen negativen Einfluss auf die Schwingfestigkeit des hier untersuchten hochfesten austenitischen Werkstoffs haben. Proben, die mit Schweißspritzern hergestellt wurden und Risse im Randbereich aufweisen, zeigen deutliche höhere Versagensschwingspielzahlen als rissfreie Referenzproben. ---------------------------------------------------------------------------------------------------------------------------------------------- In the rough conditions in the fabrication of automobile bodies, it is not always possible to avoid welding-induced imperfections such as cracks during the resistance spot welding of highstrength steels. In this respect, the influence of such cracks on the fatigue strength particularly of modern high-strength austenitic steels is not sufficiently well-known at present. The influence of welding cracks with various positions and formations was therefore investigated within the framework of this paper. In this case, the analysis of the standardised stiffness courses of specimens and the comparison of the numbers of failure stress cycles served to prove that the surface cracks produced without any spatter in the centre, interfacial region and peripheral region of the weld nugget do not have any negative influence on the fatigue strength of the high-strength austenitic material investigated here. Specimens which were manufactured with welding spatter and exhibit cracks in the peripheral region show considerably higher numbers of failure stress cycles than crack-free reference specimens. Düsseldorf Verl. für Schweißen u. Verwandte Verfahren, DVS-Verl. Deutscher Verband für Schweißen und Verwandte Verfahren 2012 Schweißen und Schneiden : Fachzeitschrift für Schweißen und verwandte Verfahren 64 1-2 28 31 2016-02-19 OPUS4-25629 Zeitschriftenartikel Heinze, Christoph; Schwenk, Christopher; Rethmeier, Michael Numerical calculation of residual stress development of multi-pass gas metal arc welding In various applications, welding-induced residual stresses have a substantial impact on the integrity of welded constructions. Tensile residual stress can promote stress-corrosion cracking, brittle fracture, and reduces the fatigue life in service, as well as influences component design due to critical stress concentrations within the component. In the present paper, a six bead multi-pass gas metal arc weld of 20 mm thick structural steel S355J2+N is experimentally and numerically investigated. The studies include transient 2D and 3D numerical calculations which consider temperature-dependent material properties, phase transformations, 'thermal' tempering, transformation plasticity, volume change due to phase transformation, an elastic–plastic material model, and isotropic strain hardening. The experimentally determined and calculated residual stresses are in a good agreement. Furthermore, the influence of the preheat and interpass temperature on welding-induced residual stresses is shown in the present investigation. Oxford Elsevier 2012 The journal of constructional steel research 72 12 19 10.1016/j.jcsr.2011.08.011 2016-02-19 OPUS4-26001 Zeitschriftenartikel Chen, Ji; Schwenk, Christopher; Wu, Chuan Song; Rethmeier, Michael Predicting the influence of groove angle on heat transfer and fluid flow for new gas metal arc welding processes This article studies the three dimensional transient weld pool dynamics and the influence of groove angle on welding of low carbon structural steel plates using the ForceArc® process. The deformation of the weld bead is also calculated with an accurate coupling of the heat transfer with fluid flow through continuity, momentum and the energy equations combined with the effect of droplet impingement, gravity, electromagnetic force, buoyancy, drag forces and surface tension force (Marangoni effect). Different angles of V groove are employed under the same welding parameters and their influence on the weld pool behavior and weld bead geometry is calculated and analyzed, which is needed for subsequent calculations of residual stress and distortion of the workpiece. Such a simulation is an effective way to study welding processes because the influence of all welding parameters can be analyzed separately with respect to heat transfer, weld pool dynamic, and microstructure of the weld. Good agreement is found between the predicted and experimentally determined weld bead cross-section and temperature cycles. It is found that the main flow pattern is more or less the same although the groove angle increases, but it will evoke larger amount of fluid to flow downward to get deeper penetration. Amsterdam Elsevier 2012 International journal of heat and mass transfer 55 1-3 102 111 10.1016/j.ijheatmasstransfer.2011.08.046 2016-02-19 OPUS4-26346 Zeitschriftenartikel Brauser, Stephan; Schwenk, Christopher; Rethmeier, Michael; Noack, T.; Jüttner, S. Influence of welding-induced cracks on the fatigue strength of resistance-spot-welded joints made of high-strength austenitic steel In the rough conditions in the fabrication of automobile bodies, it is not always possible to avoid welding-induced imperfections such as cracks during the resistance spot welding of high-strength steels. In this respect, the influence of such cracks on the fatigue strength particularly of modern high-strength austenitic steels is not sufficiently well-known at present. The influence of welding cracks with various positions and formations was therefore investigated within the framework of this paper. In this case, the analysis of the standardised stiffness courses of specimens and the comparison of the numbers of failure stress cycles served to prove that the surface cracks produced without any spatter in the centre, interfacial region and peripheral region of the weld nugget do not have any negative influence on the fatigue strength of the high-strength austenitic material investigated here. Specimens which were manufactured with welding spatter and exhibit cracks in the peripheral region show considerably higher numbers of failure stress cycles than crack-free reference specimens. Düsseldorf DVS - German Welding Society 2012 Welding and cutting 11 4 232 235 2016-02-19 OPUS4-24354 Zeitschriftenartikel Thater, Raphael; Perret, William; Schwenk, Christopher; Alber, U.; Rethmeier, Michael Industrial application of welding temperature field and distortion visualization using FEA Osaka, Japan Joining and Welding Research Institute, Osaka University (JWRI) 2010 Transactions of JWRI 39 2 232 234 2016-02-19 OPUS4-24355 Zeitschriftenartikel Schwenk, Christopher; Tikhomirov, D.; Eßer, G.; Rethmeier, Michael General standard for welding simulation Für die Abgrenzung der Anwendbarkeit verschiedener Methoden der numerischen Schweißsimulation sowie für die Vereinheitlichung der Voraussetzungen und der durchzuführenden Schritte bei der Simulation sind normative Regelwerke für den Anwender erforderlich. Da es derzeit noch keine normähnlichen Dokumente auf diesem Gebiet gibt, wurde vom Deutschen Institut für Normung e.V. DIN in Zusammenarbeit mit der Forschungsvereinigung des DVS Deutscher Verband für Schweißen und verwandte Verfahren e.V. ein Arbeitsausschuss gegründet, welcher sich mit der Erarbeitung der entsprechenden Dokumente befasst. Der vorliegende Beitrag konzentriert sich auf die Vorstellung der neuen DIN Spec 32534-1, welche die grundlegenden Simulations-Schritte erläutert und ihre Anwendungsfelder sowie die Schlüsselbegriffe spezifiziert. Des Weiteren wurde eine allgemein gültige Simulationsstruktur erarbeitet, welche als Empfehlung für den Auftraggeber und den Auftragnehmer bei der Formulierung und Abwicklung eines Dienstleistungsauftrages sowie für den Neueinstieg in die Schweißsimulation dienen soll. Schließlich wird ein Ausblick auf die weiteren Themenfelder des Arbeitsausschusses sowie auf die internationalen Aktivitäten auf diesem Gebiet gegeben. München Hanser Bundesanstalt für Materialforschung und -prüfung 2011 Materials Testing 53 9 522 527 2016-02-19 OPUS4-24558 Beitrag zu einem Sammelband Schwenk, Christopher; Tikhomirov, D. Standardisierung der numerischen Schweißsimulation Für die Abgrenzung der Anwendbarkeit verschiedener Methoden der numerischen Schweißsimulation sowie für die Vereinheitlichung der Voraussetzungen und der durchzuführenden Schritte bei der Simulation sind normative Regelwerke für den Anwender erforderlich. Da es derzeit noch keine normähnlichen Dokumente auf diesem Gebiet gibt, wurde vom DIN der Arbeitsausschuss NA 092-00-29-A "Schweißsimulation" gegründet, welcher sich mit der Erarbeitung der entsprechenden Dokumente befasst. Dieses Gremium wurde gemeinsam mit dem Gemeinschaftsausschuss FA 12 "Anwendungsnahe Schweißsimulation" der Forschungsvereinigung des DVS initiiert. Das Ziel der Normungsarbeit im Bereich der numerischen Schweißsimulation besteht in der Erarbeitung einer DIN SPEC, die die Vorgehensweisen bei der Simulation verschiedener Schweißphänomene und -verfahren langfristig standardisieren soll. In einem durch den genannten Arbeitsausschuss bereits vorbereiteten Entwurf der DIN SPEC 32534-1 wurde die Struktur des Hauptdokuments festgelegt. Im Hauptdokument sind die Anwendungsbereiche und die wesentlichen Begriffe der Schweißsimulation spezifiziert. Des Weiteren wurde die allgemein gültige Simulationsstruktur erarbeitet, welche als Empfehlung für den Auftraggeber und den Auftragnehmer bei der Formulierung und Abwicklung eines Dienstleistungsauftrages sowie für den Neueinstieg in die Schweißsimulation dienen soll. Den Schwerpunkt stellt die Vorstellung der neuen DIN SPEC mit der Erläuterung der wesentlichen Simulationsschritte dar. Im Weiteren wird auf die Klassifizierung der Unterdokumente in Abhängigkeit des Schweißverfahrens und des angestrebten Simulationsergebnisses eingegangen. Schließlich wird ein Ausblick auf die weiteren Themenfelder des Arbeitsausschusses NA 092-00-29-A "Schweißsimulation" sowie auf die internationalen Aktivitäten auf diesem Gebiet gegeben. Düsseldorf DVS Media GmbH 2011 DVS-Berichte - DVS Congress 2011 - Große Schweißtechnische Tagung 275 978-3-87155-267-0 DVS Congress 2011 - Große Schweißtechnische Tagung Hamburg, Deutschland 27.09.2011 29.09.2011 21 26 2016-02-19 OPUS4-24519 Vortrag Schwenk, Christopher Standardisierung der numerischen Schweißsimulation 2011 Große Schweißtechnische Tagung 2011, DVS Congress und DVS Expo Große Schweißtechnische Tagung 2011, DVS Congress und DVS Expo Hamburg, Germany 2011-09-27 2011-09-29 2016-02-19 OPUS4-24684 Zeitschriftenartikel Heinze, Christoph; Schwenk, Christopher; Rethmeier, Michael Effect of heat source configuration on the result quality of numerical calculation of welding-induced distortion The results of numerical welding simulations strongly depend on its temperature field. In the present paper, the temperature field of a pulsed gas metal arc weld of structural steel S355J2+N (ASTM A572 Gr. 50) with a thickness of 5 mm is experimentally and numerically investigated. In the case of temperature field validation, volumetric Gauss and double-ellipsoid Goldak heat sources are applied. Additionally, different heat source configurations, including adaptations of thermal conductivity, are analyzed regarding their influence on the calculation of welding-induced distortion. The investigations clarify the influence of heat source configurations on the calculated results, thus, contribute to an improved prediction of welding-induced distortion. Amsterdam [u.a.] Elsevier 2011 Simulation modelling practice and theory 20 1 112 123 10.1016/j.simpat.2011.09.004 2016-02-19 OPUS4-25139 Zeitschriftenartikel Perret, William; Thater, R.; Alber, U.; Schwenk, Christopher; Rethmeier, Michael Approach to assess a fast welding simulation in an industrial envrionment - application for an automotive welded part Fusion welding processes are widely used for joining metal structures, such as pipes, ships, and cars. In general, these joining processes offer a very good compromise between reliability, safety, cost and maintenance which are important issues in the current economical context. The negative heat effects of welding, i.e. distortions and residual stresses of the welded parts, are well known and many researches in this field have already been done in the last decades in order to minimize them. On the experimental side, many sophisticated procedures have become state of the art to deal with this problem. On the computational side, the improvement of the simulation algorithms and the computing power enables the simulations of many physical phenomena occurring during the welding process. The implementation of welding simulation techniques is nevertheless not an easy task and often associated with expert knowledge which hinders their global application in an industrial environment. This paper is focused on the industrial requirements of a welding simulation software with special respect to the needs of the automotive industry. The necessary information to run a welding simulation and the expectations of a weld specialist without deep knowledge in numerical methods are investigated. These expectations are tested on an automotive welded assembly with a commercially available welding simulation software designed especially for the needs of the automotive industry. A welding experiment is done and the measured temperature distributions and distortions serve as reference to validate the simulation results. The result quality of the simulations of temperature fields and distortions is in best agreement with experimental data. The workflow is well adapted for the considered industrial requirements and the time-tosolution as well as the computational costs are acceptable, whereas the efficient calibration of the heat input model is still a point which will be further investigated in current and future research works. Seoul / Berlin ; Heidelberg KSAE / Springer 2011 International journal of automotive technology 12 6 895 901 10.1007/s12239-011-0102-0 2016-02-19 OPUS4-24603 Zeitschriftenartikel Pittner, Andreas; Weiß, D.; Schwenk, Christopher; Rethmeier, Michael Fast temperature field generation for welding simulation and reduction of experimental effort The quality of welding processes is governed by the occurring induced distortions yielding an increase in production costs due to necessary reworking. Especially for more complex specimens, it is difficult to evaluate the optimal configuration of welding sequences in order to minimize the distortion. Even experienced welding operators can solve this task only by trial and error which is time and cost consuming. In modern engineering the application of welding simulation is already known to be able to analyse the heat effects of welding virtually. However, the welding process is governed by complex physical interactions. Thus, recent weld thermal models are based on many simplifications. The state of the art is to apply numerical methods in order to solve the transient heat conduction equation. Therefore, it is not possible to use the real process parameters as input for the mathematical model. The model parameters which allow calculating a temperature field that is in best agreement with the experiments cannot be defined directly but inversely by multiple simulations runs. In case of numerical simulation software based on finite discretization schemes this approach is very time consuming and requires expert users. The weld thermal model contains an initial weakness which has to be adapted by finding an optimal set of model parameters. This process of calibration is often done against few experiments. The range of model validity is limited. An extension can be obtained by performing a calibration against multiple experiments. The focus of the paper is to show a combined modelling technique which provides an efficient solution of the inverse heat conduction problem mentioned above. On the one hand the inverse problem is solved by application of fast weld thermal models which are closed form solutions of the heat conduction equation. In addition, a global optimization algorithm allows an automated calibration of the weld thermal model. This technique is able to provide a temperature field automatically that fits the experimental one with high accuracy within minutes on ordinary office computers. This fast paradigm permits confirming the application of welding simulation in an industrial environment as automotive industry. On the other hand, the initial model weakness is compensated by calibrating the model against multiple experiments. The unknown relationship between model and process parameters is approximated by a neural network. The validity of the model is increased successively and enables to decrease experimental effort, For a test case, it is shown that this approach yields accurate temperature fields within very short amount of time for unknown process parameters as input data to the model contributing to the requirement to construct a substitute system of the real welding process. Oxford Springer International Institute of Welding 2011 Welding in the world 55 09-10 83 90 2016-02-19 OPUS4-24607 Beitrag zu einem Sammelband Tang, Z.; Schempp, Philipp; Seefeld, T.; Schwenk, Christopher; Vollertsen, F. Kornfeinung beim WIG- und Laserstrahlschweißen von Aluminiumlegierungen Die Kornfeinung beim Schweißen ist mit einem Übergang von groben, stängeligen Körnern zu kleineren, globulitischen Körnern im Schweißgut verbunden. Die Feinung der Korngröße und Form führt sowohl zu einer wesentlichen Verbesserung der Schweißeignung als auch zu verbesserten mechanischen Eigenschaften. Heute gebräuchliche Schweißzusatzwerkstoffe enthalten zum Teil bereits geringe Mengen kornfeinender Zusätze, deren Wirksamkeit jedoch von einer Reihe weiterer Randbedingungen abhängt. Durch Zugabe definierter Mengen an Keimbildnern (AlTi5B1) in das Schmelzbad wurde die Abhängigkeit der Korn-größe und -form vom Titan/Bor-Gehalt untersucht. Weiterhin wurde der zur vollständigen Kornfeinung notwendige Mindestgehalt an Keimbildner für unterschiedliche Legierungen und unter unterschiedlichen Schweißbedingungen, sowohl beim WIG-Schweißen als auch beim Laserstrahlschweißen bestimmt. Die Ergebnisse zeigen, dass sich die Korngröße im Schweißgut bis auf ein Minimum von ca. 20µm verringern lässt und zugleich der Anteil der globulitischen Körner zunimmt. Der Mindestgehalt an Keimbildner für vollständige Korn-feinung hängt stark von Schweißgeschwindigkeit und Legierungszusammensetzung ab. Der Einfluss der Kornfeinung auf die Festigkeit, Duktilität sowie die Heißrissempfindlichkeit der Schweißverbindungen wird an ausgewählten Bespielen aufgezeigt. Düsseldorf DVS Media GmbH 2011 DVS-Berichte - DVS Congress 2011 - Große Schweißtechnische Tagung 275 978-3-87155-267-0 DVS Congress 2011 - Große Schweißtechnische Tagung Hamburg, Deutschland 27.09.2011 29.09.2011 153 160 2016-02-19 OPUS4-24654 Zeitschriftenartikel Schempp, Philipp; Schwenk, Christopher; Rethmeier, Michael; Cross, C.E. Weld metal grain refinement of aluminium alloy 5083 through controlled additions of Ti and B Kornfeinung im Schweißgut kann die mechanischen Eigenschaften der Schweißnaht und die Schweißeignung des Grundwerkstoffs deutlich verbessern. Eine Möglichkeit korngefeintes Schweißgut zu erreichen, ist das Versetzen des Schmelzbades mit kornfeinenden Mitteln. In dieser Studie wird gezeigt wie Titan- und Borzusätze Korngröße und -struktur von WIG-Schweißnähten der Al-Legierung 5083 (Al Mg4,5Mn0,7) beeinflussen. Dazu wurden in einem Gießprozess stäbchenförmige Einlagen hergestellt, die aus Grundwerkstoff und definierten Zusätzen der Kornfeinungslegierung Al Ti5B1 bestanden. Sie wurden als Ersatz für einen Schweißzusatzwerkstoff in einer Nut im Grundwerkstoff untergebracht und im WIG-Verfahren überschweißt. Durch die Steigerung des Titan- und Borgehalts im Schweißgut konnte dessen mittlere Korngröße deutlich verringert werden. Außerdem wurde eine Änderung der Kornstruktur beobachtet. Die Ergebnisse können als Grundlage genutzt werden, um die empfohlene chemische Zusammensetzung von Schweißzusätzen für Lichtbogenschweißen von Aluminium anzupassen. München Hanser Bundesanstalt für Materialforschung und -prüfung (BAM) 2011 Materials Testing 53 10 604 609 10.3139/120.110265 2016-02-19 OPUS4-24644 Zeitschriftenartikel Schwenk, Christopher; Rethmeier, Michael Standards and guidelines for numerical welding simulation Jixie Dianzi Gongye Bu * Harbin Hanjie Yanjiusuo 2011 Hanjie = Welding & joining 459 9 5 8 2016-02-19 OPUS4-24363 Beitrag zu einem Tagungsband Heinze, Christoph; Schwenk, Christopher; Rethmeier, Michael Zoch, H.-W.; Lübben, T. Influences on the result quality of numerical calculation of welding-induced distortion The present investigations cover different relevant influences on the numerical calculation of welding-induced distortion. Therefore, a single-layer pulsed gas metal arc (GMA) weld of structural Steel S355J2+N with a thickness Öf5 mm is experimentally and numerically investigated. The influences of mesh density, tack-welds, and continuous cooling transformation (CCT) diagrams on welding-induced distortion are studied. The quality and quantity of These effects are clarified based on the used experimental and numerical set up. The occurring differences between the investigated cases achieve significant values. Consequently, prediction of welding-induced distortion can be improved considering the present investigations. IWT 2011 IDE 2011 - 3rd International conference on distortion engineering 2011 (Proceedings) 978-3-88722-724-1 IDE 2011 - 3rd International conference on distortion engineering 2011 Bremen, Germany 14.09.2011 16.09.2011 277 285 2016-02-19 OPUS4-24820 Zeitschriftenartikel Heinze, Christoph; Schwenk, Christopher; Rethmeier, Michael The effect of tack welding on numerically calculated welding-induced distortion A single-layer pulsed gas metal arc weld of structural steel S355J2+N with a thickness of 5 mm is experimentally and numerically investigated. Two tack welds are considered in the numerical simulation into two different ways. First, the tack welds are represented by elements belonging to the initial material. This implies that the 'tack weld material' was not exposed to any thermal load or phase transformation before actual welding was performed. The weld seam is shortened and there is an influence on the stiffness of the whole structure affecting the calculation result. Secondly, the tack welds were simulated as conducted in the experimental welding procedure. The cases considering tack welding are compared to a simulation neglecting tack welding and to the experimental results. The influence of tack welds on the calculated welding-induced distortion is clarified and a contribution to an improved simulation-based prediction of welding-induced distortion is possible by modeling tack welding according to the realistic fabrication procedure. Amsterdam Elsevier 2012 Journal of materials processing technology 212 1 308 314 10.1016/j.jmatprotec.2011.09.016 2016-02-19 OPUS4-25028 Zeitschriftenartikel Schwenk, Christopher; Rethmeier, Michael Material properties for welding simulation - measurement, analysis, and exemplary data Welding is a key technology in the area of industrial production due to its flexibility and efficiency. However, new materials and welding techniques necessitate permanent research activities in order to keep up with the demands. A detailed knowledge about the process itself and the heat effects of welding, e.g., temperatures, distortions, and stresses, is the basis for a target-oriented optimization instead of a trial-and-error approach. Numerical welding simulation is a powerful tool to meet these demands. Complementary to an experimental investigation, it enables the analysis of the specimen during the welding process, commonly known as computational welding mechanics (CWM). Whereas simulation is nowadays a common tool in different development processes, the modeling of welding still remains difficult because of the multiple physical effects taking place. One of the most important problems for the user is the lack of knowledge about the material properties as input data for the simulation. Furthermore, any scattering of the data causes uncertainties that can have major effects on the calculations. The objective of this paper is to give an overview about the experimental determination and analysis of the material properties needed as input data for a welding simulation. The measurement techniques and the occurring deviations of the results are discussed. Additionally, the collected data for three representative alloys (dual-phase steel, austenitic steel, precipitation-hardenable aluminum alloy) are analyzed. Finally, the temperature-dependent thermophysical and thermomechanical material properties for these three alloys are given in a ready-to-use format for a numerical welding simulation. New York, NY American Welding Society Welding Research Council 2011 Welding journal 90 220-s 227-s 2016-02-19 OPUS4-25029 Zeitschriftenartikel Perret, William; Thater, Raphael; Alber, U.; Schwenk, Christopher; Rethmeier, Michael Case study for welding simulation in the automotive industry Welding is one of the most widely used joining processes in structural applications, like in car body production in the automotive industry. It is well-known that distortions and residual stresses occur during and after the welding process. Many procedures exist to decrease these negative heat effects of welding, but are often coupled with highly cost intensive experiments. For several decades, simulation models have been developed to understand and predict the heat effects of welding and to reduce experimental effort. In the production planning of various Original Equipment Manufacturers (OEM), some simulation tools are already well established, e.g. for crash test, forming or casting simulations. For welding, the demand is high but the implementation of welding simulation software is still not established yet. Welding is a complex process and the development of a flexible simulation tool, which produces good simulation results without expert knowledge in simulation, is not an easy task. In this paper, a welded assembly from the automotive industry has been simulated and compared to experimental data. Temperature fields and transient distortion distributions have been measured with thermocouples and with an optical 3D deformations analysis tool, respectively. The simulation has been run with a commercially available welding simulation software. The simulated temperature fields match the numerical ones perfectly. The simulated distortions are also qualitatively in best agreement with the experimental ones. Quantitatively, a difference of approximately 20 % between the simulated and the measured distortions is visible; this is acceptable considering the simplifications and assumptions of the simulation model. The global time to solution to get these results without expert knowledge in welding simulation was between 4 and 6 weeks, which is a reasonable time frame for an industrial application of welding simulation. Oxford Springer International Institute of Welding 2011 Welding in the world 55 11/12 89 98 10.1007/BF03321546 2016-02-19 OPUS4-25036 Zeitschriftenartikel Heinze, Christoph; Schwenk, Christopher; Rethmeier, Michael Numerical calculation of residual stress development of multi-pass gas metal arc welding under high restraint conditions During welding, residual stresses build-up created by the steep thermal gradient that occurs in the weld zone from localized heating and cooling, and phase transformations appearing in low-alloyed structural steel is inevitable. Welding of rather simple test plates do not cover the actual structural effects, which have to be considered during real component welding. However, the resulting welding-induced residual stress state is highly influenced by the structural characteristics, i.e. restraint conditions, of the welded construction. Therefore, a unique large-scale testing facility providing a specific shrinkage restraint while welding and subsequent cooling was used for the present investigations. Hereby, a six bead multi-pass gas metal arc weld of 20 mm thick structural steel S355J2 + N was welded under shrinkage restraint. The residual stresses were experimentally and numerically investigated, and compared to an analysis of plates welded under force-free support and free shrinkage conditions. The experimentally determined and calculated residual stresses using both 2D and 3D numerical models are in a good agreement. Furthermore, the influence of a shrinkage restraint on the residual stress distribution is both experimentally and numerically shown for the present test set-up. Oxford Elsevier Science 2011 Materials and design 35 201 209 10.1016/j.matdes.2011.09.021 2016-02-19 OPUS4-18300 Zeitschriftenartikel Pittner, Andreas; Weiß, D.; Schwenk, Christopher; Rethmeier, Michael Methodology to improve applicability of welding simulation The objective of this paper is to demonstrate a new simulation technique which allows fast and automatic generation of temperature fields as input for subsequent thermomechanical welding simulation. The basic idea is to decompose the process model into an empirical part based on neural networks and a phenomenological part that describes the physical phenomena. The strength of this composite modelling approach is the automatic calibration of mathematical models against experimental data without the need for manual interference by an experienced user. As an example for typical applications in laser beam and GMA-laser hybrid welding, it is shown that even 3D heat conduction models of a low complexity can approximate measured temperature fields with a sufficient accuracy. In general, any derivation of model fitting parameters from the real process adds uncertainties to the simulation independent of the complexity of the underlying phenomenological model. The modelling technique presented hybridises empirical and phenomenological models. It reduces the model uncertainties by exploiting additional information which keeps normally hidden in the data measured when the model calibration is performed against few experimental data sets. In contrast, here the optimal model parameter set corresponding to a given process parameter is computed by means of an empirical submodel based on relatively large set of experimental data. The approach allows making a contribution to an efficient compensation of modelling inaccuracies and lack of knowledge about thermophysical material properties or boundary conditions. Two illustrating examples are provided. London Maney Institute of Materials, Minerals and Mining 2008 Science and technology of welding and joining 13 6 496 508 10.1179/136217108X329322 2016-02-19 OPUS4-18278 Beitrag zu einem Tagungsband Schwenk, Christopher; Rethmeier, Michael H.-W. Zoch, ; T. Lübben, Distortion optimisation of beam-welded industrial parts by means of numerical welding simulation 2008 2nd International Conference on Distortion Engineering (IDE 2008), September 17-19, 2008, Bremen (Proceedings) 2nd International Conference on Distortion Engineering (IDE 2008) Bremen, Germany 2008-09-17 2008-09-19 483 490 2016-02-19 OPUS4-18290 Beitrag zu einem Sammelband Pittner, Andreas; Weiss, D.; Schwenk, Christopher; Rethmeier, Michael A methodology for the fast temperature field generation for welding simulation Cambridge TWI 2008 Proceedings of the 17th International Conference Computer Technology in Welding and Manufacturing 978-1-903761-07-6 17th International Conference "Computer Technology in Welding and Manufacturing" Cranfield, UK 2008-06-18 2008-06-19 1 12 2016-02-19 OPUS4-16500 Zeitschriftenartikel Tikhomirov, D.; Rietman, B.; Schwenk, Christopher; Franz, T. Methoden der Schweißverzugssimulation für die Anwendung in der Automobilindustrie In diesem Artikel wird eine Übersicht über die Methoden zurnumerischen Berechnung schweißbedingter Bauteilverzüge fürindustrielle Anwendungen gegeben. Zunächst werden die Anforderungen der Automobilindustrie an die benötigte Softwaredargestellt. Dabei wird zwischen der industriellen Forschungund der Entwicklung/Produktionsplanung differenziert. Es werden die verschiedenen derzeit verfügbaren Ansätze zur numerischen Schweißsimulation vorgestellt und deren Möglichkeitenzur Erfüllung der dargestellten Bedürfnisse erläutert. Anhand eines aktuellen Bauteils aus der Automobilindustrie (B-SäuleVW Golf) wird beispielhaft die Verzugsoptimierung mit Hilfe einer Berechnungsmethodik aufgezeigt, welche sich durch eine schnelle Modellerstellung, kurze Rechenzeiten und einfache Handhabung auszeichnet. Ein Vergleich der Simulationsergebnisse mit experimentell ermittelten Daten zeigt sehr gute Über-einstimmungen und verdeutlicht das immense Potenzial einer numerisch unterstützten Prozessoptimierung. Düsseldorf Verl. für Schweißen u. Verwandte Verfahren, DVS-Verl. Deutscher Verband für Schweißen und Verwandte Verfahren 2007 Schweißen und Schneiden : Fachzeitschrift für Schweißen und verwandte Verfahren 59 12 678 680 2016-02-19 OPUS4-16488 Beitrag zu einem Sammelband Schwenk, Christopher; Rethmeier, Michael; Dilger, K.; Michailov, V. H.K.D.H. Bhadeshia, ; H. Cerjak, ; E. Kozeschnik, Sensitivity Analysis of Welding Simulation Depending on Material Properties Value Variation Graz, Austria Technische Universität Graz 2007 Mathematical Modelling of Weld Phenomena 8 978-3-902465-69-6 1107 1128 2016-02-19 OPUS4-16489 Beitrag zu einem Sammelband Roeren, S.; Schwenk, Christopher; Rethmeier, Michael H.K.D.H. Bhadeshia, ; H. Cerjak, ; E. Kozeschnik, Different approaches to model clamping conditions within a welding simulation Graz, Austria Technische Universität Graz 2007 Mathematical Modelling of Weld Phenomena 8 978-3-902465-69-6 1093 1106 2016-02-19 OPUS4-16490 Beitrag zu einem Sammelband Schwenk, Christopher; Rethmeier, Michael; Dilger, K. H.K.D.H. Bhadeshia, ; H. Cerjak, ; E. Kozeschnik, Analysis of the transient deformation behaviour and numerical optimisation of an electron beam welded gearwheel Graz, Austria Technische Universität Graz 2007 Mathematical Modelling of Weld Phenomena 8 978-3-902465-69-6 1155 1166 2016-02-19 OPUS4-16491 Beitrag zu einem Sammelband Schwenk, Christopher; Rethmeier, Michael; Weiss, D. H.K.D.H. Bhadeshia, ; H. Cerjak, ; E. Kozeschnik, Rapid generation of temperature fields for simulation of welding distortions Graz, Austria Technische Universität Graz 2007 Mathematical Modelling of Weld Phenomena 8 978-3-902465-69-6 835 846 2016-02-19 OPUS4-17447 Beitrag zu einem Tagungsband Schwenk, Christopher; Rethmeier, Michael F. Vollertsen, ; J. Sakkiettibutra, Influence of Material Properties on Numerically Calculated Welding Distortions Bremer Institut für angewandte Strahltechnik (BIAS) 2008 International Workshop on Thermal Forming and Welding Distortion (IWOTE `08), April 22-23, 2008, Bremen (Proceedings) International Workshop on Thermal Forming and Welding Distortion (IWOTE `08) Bremen, Germany 2008-04-22 2008-04-23 35 44 2016-02-19 OPUS4-17740 Beitrag zu einem Sammelband Schwenk, Christopher Thomas Böllinghaus, ; Masaki Kitagawa, ; Teruo Kishi, ; Jürgen Lexow, Measurement and analysis of material properties needed for numerical welding simulation Tsukuba, Ibaraki, Japan National Institute for Materials Science (NIMS) 2008 1st World Materials Research Institutes Forum (WMRIF) - Workshop for young materials scientists, July 22-25, 2008, Tsukuba, Ibaraki, Japan (Proceedings) 978-4-9900563-3-9 1st World Materials Research Institutes Forum (WMRIF) - Workshop for young materials scientists Tsukuba, Ibaraki, Japan 2008-07-22 2008-07-25 XX-1 - XX-10 2016-02-19 OPUS4-15725 Vortrag Schwenk, Christopher Influence of material property values on result accuracy of FE welding simulation 2007 5. Deutsch-Japanisches Seminar, Frauenhofer Institut Werkstoffmechanik iwm 5. Deutsch-Japanisches Seminar, Frauenhofer Institut Werkstoffmechanik iwm Freiburg, Germany 2007-06-27 2007-06-28 2016-02-19 OPUS4-16103 Vortrag Schwenk, Christopher Anwendungsmöglichkeiten der Schweißsimulation zur Analyse und Verbesserung der Sicherheit gefügter Bauteile 2007 SYSWELD Forum 2007, Bauhaus-Universität Weimar, Professur Stahlbau SYSWELD Forum 2007, Bauhaus-Universität Weimar, Professur Stahlbau Weimar, Germany 2007-11-15 2016-02-19 OPUS4-19639 Beitrag zu einem Tagungsband Pittner, Andreas; Weiss, D.; Schwenk, Christopher; Rethmeier, Michael V.I. Makhnenko, Fast generation and prediction of welding temperature fields for multiple experiments The objective of this paper is to demonstrate a new simulation technique which allows the fast and automatic generation to temperature fields based on a combination of empirical and phenomenological modelling techniques. The automatic calibration of the phenomenological model is performed by a multi-variable global optimisation routine which yields the optimal fit between simulated and experimental weld charcteristics without the need for initial model parameters. For exemplary welding processes it is shown that linear 3D heat conduction models can approximate measured temperature fields with a high accuracy. The modelling approach presented comprises the automatic calibration against multiple experiments which permits simulating the temperature field for unknown process parameters. The validation of this composite simulation model is performed for exemplary welding processes and includes the prediction of the fusion line in the cross section and the corresponding thermal cycles. Kiev, Ukraine E.O. Paton Electric Welding Institute of the NAS of Ukraine 2008 Mathematical modelling and information technologies in welding and related processes - 4th International Conference (Proceedings) 4th International Conference - Mathematical modelling and information technologies in welding and related processes Katsiveli, Crimea, Ukraine 2008-05-27 2008-05-30 134 140 2016-02-19 OPUS4-19744 Forschungsbericht Pittner, Andreas; Weiss, D.; Schwenk, Christopher; Rethmeier, Michael Fast temperature field generation for welding simulation and reduction of experimental effort The quality of welding processes is governed by the occurring induced distortions yielding an increase in production costs due to necessary reworking. Especially for more complex specimens it is difficult to evaluate the optimal configuration of welding sequences in order to minimise the distortion. Even experienced welding operators can solve this task only by trial and error which is time and cost consuming. In modern engineering the application of welding simulation is already known to be able to analyse the heat effects of welding virtually. However, the welding process is governed by complex physical interactions. Thus, recent weld thermal models are based on many simplifications. The state of the art is to apply numerical methods in order to solve the transient heat conduction equation. Therefore, it is not possible to use the real process parameters as input for the mathematical model. The model parameters which allow calculating a temperature field that is in best agreement with the experiments cannot be defined directly but inversely by multiple simulations runs. In case of numerical simulation software based on finite discretisation schemes this approach is very time consuming and requires expert users. The weld thermal model contains an initial weakness which has to be adapted by finding an optimal set of model parameters. This process of calibration is often done against few experiments. The range of model validity is limited. An extension can be obtained by performing a calibration against multiple experiments. The focus of the paper is to show a combined modelling technique which provides an efficient solution of the inverse heat conduction problem mentioned above. On the one hand the inverse problem is solved by application of fast weld thermal models which are closed form solutions of the heat conduction equation. In addition, a global optimisation algorithm allows an automated calibration of the weld thermal model. This technique is able to provide a temperature field automatically that fits the experimental one with high accuracy within minutes on ordinary office computers. This fast paradigm permits confirming the application of welding simulation in an industrial environment as automotive industry. On the other hand, the initial model weakness is compensated by calibrating the model against multiple experiments. The unknown relationship between model and process parameters is approximated by a neural network. The validity of the model is increased successively and enables to decrease experimental effort. For a test case it is shown, that this approach yields accurate temperature fields within very short amount of time for unknown process parameters as input data to the model contributing to the requirement to construct a substitute system of the real welding process. Paris International Institute of Welding 2009 IIW Document SC-Auto-32-09 1 11 2016-02-19 OPUS4-19727 Vortrag Schwenk, Christopher Fast Temperature Field Generation for Welding Simulation and Reduction of Experimentall Effort 2009 Präsentation Institutskolloquium Prof. C.S. Wu, Shangdong University Präsentation Institutskolloquium Prof. C.S. Wu, Shangdong University Jinan, China 2009-07-08 2016-02-19 OPUS4-22705 Zeitschriftenartikel Schwenk, Christopher; Rethmeier, Michael Distortion optimisation of beam-welded industrial parts by means of numerical welding simulation Genève, Switzerland Inderscience Enterprises Ltd 2010 international journal of microstructure and materials properties 5 4/5 412 422 2016-02-19 OPUS4-22721 Beitrag zu einem Tagungsband Thater, Raphael; Perret, William; Schwenk, Christopher; Alber, U.; Rethmeier, Michael Industrial application of welding temperature field and distortion visualization using FEA The non-uniform heat input during the welding process leads to problematic permanent deformations of welded parts. The control of these welding distortions is, with the absence of the knowledge of the fundamental mechanisms responsible for these deformations, an extremely time and cost consuming iterative "trial-and-error" optimization process. The visualization of the involved physical phenomena, like temperature and distortions, .is an indispensable tool to clearly identify these mechanisms in order to adapt the welding parameters and clamping conditions target-oriented. Both experimental and virtual methods exist to obtain these physical data, however the possibilities to visualize them with experimental methods are laborious, expensive and limited in their application. Welding Simulation using finite element analysis (FEA) offers many benefits and has a great potential to reduce the experimental effort. Nevertheless, the industrial application of welding Simulation is not yet established widely because of reservations regarding the computation costs and the resulting accuracy for instance. In this paper, the results of a case study for a welding Simulation with an industrial background are presented. A welded assembly from the automotive industry has been investigated with numerical and experimental methods. A comparison between both methods demonstrates the Potentials of welding Simulation in terms of visualization. Furthermore, the numerical results reveal the possibilities of current resources. regarding calculation time and result accuracy of an industrial applied welding Simulation. Joining and Welding Research Institute, Osaka University (JWRI) 2010 VISUAL-JW 2010 - The international symposium on visualization in joining & welding science through advanced measurements and simulation (Proceedings) 1 VISUAL-JW 2010 - The international symposium on visualization in joining & welding science through advanced measurements and simulation Osaka, Japan 11.11.2010 12.11.2010 PT-31 245 246 2016-02-19 OPUS4-23519 Beitrag zu einem Tagungsband Schwenk, Christopher; Tikhomirov, D.; Eßer, G.; Rethmeier, Michael General standard for welding simulation For differentiating the applicability of various numerical welding Simulation methods as well as unifying the prerequisites and the Steps to be taken in Simulation, normative codes are required for the user. Since any standard-like documents are currently still lacking in this field, DIN German Institute for Standardization has set up the Standards Committee NA 092-00-29-AA "Welding Simulation" dealing with the preparation of respective documents. This committee was initiated in partnership with the joint committee FA 12 "Weld Simulation on Application" of the Research Association of DVS German Welding Society. The objective of this Standardization work in the field of numerical welding Simulation is to prepare a DIN SPEC with a view to standardizing the approaches to the Simulation of various welding phenomena and processes over the long run. In a draft version of DIN SPEC 32534 that has already been prepared by the above mentioned Committee, the structure of the primary document was stated. The primary document specifies the application fields and the key terms of welding Simulation. In addition, the generally valid Simulation structure has been established which is intended to serve as a recommendation for customers and suppliers in formulating and handling a Service order as well as for persons who Start doing welding Simulation for the first time. This article focuses on the presentation of the new DIN SPEC 32534-1 explaining the major Simulation Steps. It additionally addresses the Classification of the secondary documents depending on the welding process and on the desired Simulation result. Finally, it gives an overview of the other subject areas dealt with in the Standards Committee NA 092-00-29-AA "Welding Simulation" as well as of the international activities in this field. International Institute of Welding (IIW) 2011 IIW SC-Auto Intermediate Meeting IIW SC-Auto Intermediate Meeting Ijmuiden, The Netherlands 11.04.2011 12.04.2011 SC-Auto-44-11 1 10 2016-02-19 OPUS4-23517 Zeitschriftenartikel Schwenk, Christopher Developing guidelines for numerical welding simulation A goal of industry is to fully map the fabrication process — from the blank metal through the individual fabrication steps all the way to the end product — in a so-called "virtual process chain." The concept of continuous simulation of all relevant fabrication segments is intended not only to achieve a reduction in development and fabrication costs, but most of all to optimize products and fabrication procedures. An essential link in this virtual process chain is welding simulation. New York, NY American Welding Society Welding Research Council 2011 Welding journal April 49 51 2016-02-19 OPUS4-20674 Beitrag zu einem Sammelband Heinze, Christoph; Schwenk, Christopher; Rethmeier, Michael Experimentelle und numerische Analyse des Geometrieeinflusses auf den Schweißeigenspannungszustand Die vorliegende Arbeit stellt Untersuchungen im Rahmen eines Forschungsprojektes mit Schwerpunkt in der experimentellen und numerischen Analyse schweißbedingter Eigenspannungen und Verzüge beim Mehrlagenschweißen dar. Das Auftreten von kritischen Eigenspannungszuständen und untolerierbaren Verzügen während des Fertigungsprozesses verursacht durch erforderliche Nacharbeiten, wie z.B. Richten oder Wärmenachbehandlungen, zusätzliche Kosten. Diese Nacharbeiten können vermieden werden, wenn die numerische Schweißsimulation auf der Grundlage von zuverlässigen Berechnungsergebnissen zur Optimierung angewandt wird. Die Analyse des Eigenspannungszustandes erfolgt an 5 mm dicken Blechen des unlegierten Baustahls S355J2, wobei Stumpfnaht-Verbindungen mittels Metall-Aktiv-Gas-(MAG)-Schweißen ausgeführt worden sind. Im Zusammenhang mit den Experimenten werden sowohl Temperaturzyklen und Eigenspannungen gemessen als auch Schmelzbadgeometrie und Mikrostruktur ermittelt. Auf der Basis eines experimentell validierten Temperaturfeldes und umfangreichen röntgenografischen Eigenspannungsuntersuchungen erfolgen numerische Strukturberechnungen. Die auftretenden Phasenumwandlungen werden in der Simulation berücksichtigt. Die Betrachtung verschiedener Blechkonfigurationen gibt den Einfluss der Blechlänge auf das Niveau der entstehenden Eigenspannungen wieder. Es stellt sich heraus, dass sich die Quereigenspannungen in den nahtnahen Bereich mit zunehmender Blechlänge in den Druckbereich verschieben. Dieses Verhalten kann durch die experimentell validierte Struktursimulation des vorliegenden Prozesses numerisch abgebildet werden und schafft somit den Ausgangspunkt für die spätere Berechnung von mehrlagigen Schweißnähten. Universitätsverlag Weimar Bauhaus Universität Weimar 2009 SYSWELD Forum 2009 978-3-86068-401-6 SYSWELD Forum 2009 Weimar, Deutschland 2009-10-22 2009-10-23 62 74 2016-02-19 OPUS4-20793 Zeitschriftenartikel Babu, S. S.; Sonnenberg, G.; Schwenk, Christopher; Goldak, J.; Porzner, H.; Khurana, S.P.; Zhang, W.; Gayler, J. How can computational weld mechanics help industry? New York, NY American Welding Society Welding Research Council 2010 Welding journal 89 1 40 45 2016-02-19 OPUS4-20882 Beitrag zu einem Tagungsband Pittner, Andreas; Schwenk, Christopher; Weiß, D.; Rethmeier, Michael Application of a combined modelling technique to reduce experimental effort - a case study for laser-GMA-hybrid welding Saint Petersburg, Russia Saint Petersburg state polytechnic university 2009 VI. International conference "Beam technologies & laser application" VI. International conference "Beam technologies & laser application" Saint Petersburg, Russia 2009-09-23 2009-09-25 97 102 2016-02-19 OPUS4-20797 Beitrag zu einem Tagungsband Schwenk, Christopher; Rethmeier, Michael Simulation based approach for distortion analysis and optimisation of beam welded automotive parts Saint Petersburg, Russia Saint Petersburg state polytechnic university 2009 VI. International conference "Beam technologies & laser application" VI. International conference "Beam technologies & laser application" Saint Petersburg, Russia 2009-09-23 2009-09-25 1 9(?) 2016-02-19 OPUS4-20814 Vortrag Schwenk, Christopher Simulation Based Approach for Distortion Analysis and Optimisation of Beam Welded Automotive Parts 2009 Beam Technologies & Laser Application, Abstracts of papers, VI International Conference Beam Technologies & Laser Application, Abstracts of papers, VI International Conference Saint Petersburg, Russia 2009-09-23 2009-09-25 2016-02-19 OPUS4-20887 Zeitschriftenartikel Perret, William; Schwenk, Christopher; Rethmeier, Michael Comparison of analytical and numerical welding temperature field calculation Analytical and numerical methods are used to estimate the temperature field due to the heat effects of welding. Numerical techniques are more adapted for industrial complex applications where analytical solutions do not exist yet. However, computational time is much lower with analytical models and a combination of both methods is investigated. Therefore, the two approaches are introduced and confronted in this paper. The finite-element software Ansys has been used for numerical simulations and Scilab for analytical simulations. In order to get a similar result quality, both methods have to be analysed and compared with respect to boundary conditions. These configurations are presented in this paper. Before starting any analysis, the analytical and numerical models have to be comparable. For the numerical simulation, every in- or output is given in discrete form and, for the analytical simulation, in continuous form. Thus, an analysis of the energy input distribution in both models is compulsory to ensure that the same amount of energy is applied. After this first study, a comparison of the analytical and numerical temperature field simulation is done from a fix point source in an infinite volume in steady state to a moving point source in a finite dimension in a transient state. A good agreement between the analytical and the numerical simulation results is found. However, some techniques, like a consideration of an image heat source for the analytical model or the selection of boundary conditions for the numerical model, need to be taken into consideration when the degree of complexity of the study (finite dimension or cooling time) increases. The limit of the comparison is reached when the geometry becomes too complex and when the effect of variable thermal properties with temperature cannot be neglected. Amsterdam Elsevier 2010 Computational materials science 47 4 1005 1015 10.1016/j.commatsci.2009.11.032 2016-02-19 OPUS4-21169 Vortrag Schwenk, Christopher Strukturierte Vorgehensweise zur Simulation schweißbedingter Verzüge und Eigenspannungen 2010 INS-Vortragsforum Hannover-Messe 2010 (Präsentation zum abgeschlossenen INS-Vorhaben) INS-Vortragsforum Hannover-Messe 2010 (Präsentation zum abgeschlossenen INS-Vorhaben) Hanover, Germany 2010-04-20 2016-02-19 OPUS4-21213 Vortrag Schwenk, Christopher Optimierung von Verzug und Eigenspannungen beim Schweißen dickwandiger Bauteile 2010 Kolloquium "Schweißbedingter Verzug - Möglichkeiten der Vorausberechnung" Präsentation zu AiF Vorhaben IG 15746 N Kolloquium "Schweißbedingter Verzug - Möglichkeiten der Vorausberechnung" Präsentation zu AiF Vorhaben IG 15746 N Braunschweig, Germany 2010-04-22 2016-02-19 OPUS4-22238 Zeitschriftenartikel Schenk, T.; Schwenk, Christopher Material response of GMA welded 1 mm thick DP600 overlap joints In a previously published model, gas metal arc welding of 1 mm thick DP600 overlap joints is validated for the transient temperature distribution, the welding distortion and longitudinal residual stresses. Tensile tests have been simulated and performed experimentally. Validations were performed for two clamping cases: an immediate release of the clamps after welding and a release of the clamps after cooling to room temperature. There is good agreement between experiments and simulations. It has been found that the temperature distribution, longitudinal stresses and welding distortions are dependent on the clamping conditions. To explain the effect of the clamping time, a bar model is proposed. It is shown that longer clamping times increase plastic deformation and hence reduce residual stresses and buckling distortion. Additionally for an overlap joint, it has been found that the longitudinal residual stresses are affected significantly by the sample's geometry. London Maney Institute of Materials, Minerals and Mining 2010 Science and technology of welding and joining 15 7 567 574 10.1179/136217110X12714217309777 2016-02-19 OPUS4-22541 Beitrag zu einem Tagungsband Perret, William; Thater, R.; Alber, U.; Schwenk, Christopher; Rethmeier, Michael Case study for welding simulation in the automotive industry 2010 INPRO - Intermediate meeting - IIW-Select committee "automotive and road transport" INPRO - Intermediate meeting - IIW-Select committee "automotive and road transport" 2010-04-21 2010-04-22 IIW-Doc. No. SC-Auto-37-10 1 13 2016-02-19 OPUS4-23153 Beitrag zu einem Sammelband Schwenk, Christopher; Rethmeier, Michael Cerjak, H.; Enzinger, N. Structured approach for a transient 3D numerical welding simulation Verlag der Technischen Universität Graz 2010 Mathematical modelling of weld phenomena 9 978-3-85125-127-2 901 917 2016-02-19 OPUS4-23154 Beitrag zu einem Sammelband Pittner, Andreas; Schwenk, Christopher; Weiß, D.; Rethmeier, Michael Cerjak, H.; Enzinger, N. An efficient solution of the inverse heat conduction problem for welding simulation Verlag der Technischen Universität Graz 2010 Mathematical modelling of weld phenomena 9 978-3-85125-127-2 761 791 2016-02-19 OPUS4-23835 Zeitschriftenartikel Heinze, Christoph; Schwenk, Christopher; Rethmeier, Michael; Caron, J. Numerical sensitivity analysis of welding-induced residual stress depending on variations in continuous cooling transformation behavior The usage of continuous cooling transformation (CCT) diagrams in numerical welding simulations is state of the art. Nevertheless, specifications provide limits in chemical composition of materials which result in different CCT behavior and CCT diagrams, respectively. Therefore, it is necessary to analyze the influence of variations in CCT diagrams on the developing residual stresses. In the present paper, four CCT diagrams and their effect on numerical calculation of residual stresses are investigated for the widely used structural steel S355J2 + N welded by the gas metal arc welding (GMAW) process. Rather than performing an arbitrary adjustment of CCT behavior, four justifiable data sets were used as input to the numerical calculation: data available in the Sysweld database, experimental data acquired through Gleeble dilatometry tests, and TTT/CCT predictions calculated from the JMatPro and Edison Welding Institute (EWI) Virtual Joining Portal software. The performed numerical analyses resulted in noticeable deviations in residual stresses considering the different CCT diagrams. Furthermore, possibilities to improve the prediction of distortions and residual stress based on CCT behavior are discussed. Secaucus, N.J. ; Heidelberg Springer ; [Beijing] : Higher Education Press 2011 Frontiers of materials science in China 5 2 168 178 10.1007/s11706-011-0131-7 2016-02-19 OPUS4-26992 Zeitschriftenartikel Schempp, Philipp; Cross, Carl Edward; Schwenk, Christopher; Rethmeier, Michael Influence of Ti and B additions on grain size and weldability of aluminium alloy 6082 Grain refinement is an important possibility to enhance the weldability of aluminium weld metal that is usually defined by its susceptibility to solidification cracking. In this study, grain refinement was achieved through the addition of commercial grain refiner containing titanium and boron to the GTA weld metal of aluminium alloy 6082. The weld metal mean grain size could be reduced significantly from about 70 µm to a saturated size of 21 µm with a change in grain shape from columnar to equiaxed. The grain refinement prevented the formation of centreline solidification cracking that was present only in welds with unrefined grain structure. A variation of torch speed led to a strong change of solidification parameters such as cooling rate that was measured in the weld metal and the corresponding solidification rate and thermal gradient. The ratio thermal gradient/growth rate (G/R) decreased from 50 K s/mm² (high torch speed) to 10 K s/mm² (low torch speed). However, the variation of torch speed did not change the tendency for solidification cracking. The microstructure of unrefined and completely refined weld metal was compared. The observed change in size and distribution of the interdendritic phases was related to the change in susceptibility to solidification cracking. Oxford Springer International Institute of Welding 2012 Welding in the world 56 09/10 95 104 2016-02-19 OPUS4-19826 Zeitschriftenartikel Pittner, Andreas; Schwenk, Christopher; Rethmeier, Michael; Weiß, D. Automated generation of temperature fields for numerical welding simulation Tokyo, Japan Yosetsu Gakkai 2009 Quarterly journal of the Japan Welding Society 27 2 219 224 2016-02-19 OPUS4-22038 Zeitschriftenartikel Tikhomirov, D.; Schwenk, Christopher Efficient numerical welding simulation through standardisation Düsseldorf DVS - German Welding Society 2010 Welding and cutting 9 5 292 295 2016-02-19 OPUS4-22041 Zeitschriftenartikel Tikhomirov, D.; Schwenk, Christopher Effiziente numerische Schweißsimulation durch Standardisierung Düsseldorf Verl. für Schweißen u. Verwandte Verfahren, DVS-Verl. Deutscher Verband für Schweißen und Verwandte Verfahren 2010 Schweißen und Schneiden : Fachzeitschrift für Schweißen und verwandte Verfahren 62 9 519 523 2016-02-19 OPUS4-21444 Zeitschriftenartikel Caron, J.; Heinze, Christoph; Schwenk, Christopher; Rethmeier, Michael; Babu, S. S.; Lippold, J. Effect of continuous cooling transformation variations on numerical calculation of welding-induced residual stresses Continuous cooling transformation (CCT) behavior affects the transient state of material properties employed in a numerical welding simulation, having a direct influence on the developing stress state. Three different CCT diagrams for S355J2 steel were employed to understand the influence of variations in CCT behavior on the numerical calculation of welding-induced residual stresses. The CCT diagrams were constructed from transformation data contained in the Sysweld software database, measured dilatometric data from Gleeble experiments, and transformation data calculated from the JMatPro software. The calculated transverse and longitudinal residual stress distributions provided a qualitative correction only in comparison to experimental measurements, with the largest deviation occurring near the weld interface. Overall, the results indicate a weak dependency of the calculated residual stresses due to anticipated CCT variations. The most significant effect on the calculated residual stresses was shown to be related to the proportion of formed martensite. It is suggested that CCT data of approximate accuracy is sufficient for reliable calculation of welding-induced residual stresses. New York, NY American Welding Society Welding Research Council 2010 Welding journal 89 151-s - 160-s 2016-02-19 OPUS4-21447 Zeitschriftenartikel Schwenk, Christopher Normen und Richtlinien für die numerische Schweißsimulation - Entwicklungsbegleitende Normung (EBN) Die Schweißsimulation ermöglicht frühzeitige Aussagen über schweißbedingte Phänomene und hilft so, den Entwicklungsprozess zu verbessern. Damit können die Ursachen auftretender Qualitätseinbußen besser identifiziert werden, sodass eine gezielte Vorgehensweise für die Bauteil- und Verfahrensoptimierung möglich wird. Das wirtschaftliche Anwendungspotenzial der Schweißsimulation ist enorm und mit dem der Umformsimulation vergleichbar. Bei unsachgemäßer Anwendung ist das Fehlerpotenzial jedoch sehr hoch, wodurch die Notwendigkeit einer strukturierten und definierten Vorgehensweise verdeutlicht wird. Hiermit werden nicht nur die Zuverlässigkeit und Aussagekraft der Simulationen sichergestellt, sondern auch eine Grundlage zur effektiven Vergleichbarkeit verschiedener Berechnungsprojekte geschaffen. Diese Sicherheit ist sowohl für Auftraggeber als auch für Auftragnehmer wichtig und hilft, die industrielle Anwendung der Schweißsimulation zu unterstützen und ihr Potenzial voll auszuschöpfen. Berlin Beuth Deutsches Institut für Normung 2010 DIN-Mitteilungen + Elektronorm 6 28 31 2016-02-19 OPUS4-21469 Vortrag Schwenk, Christopher Fügetechnik am IPK und der BAM 2010 Kolloquium "Synergie von Werkstoff- und Prozesstechnik" Kolloquium "Synergie von Werkstoff- und Prozesstechnik" Berlin, Germany 2010-06-04 2016-02-19 OPUS4-23283 Zeitschriftenartikel Tikhomirov, D.; Schwenk, Christopher Efficient numerical welding simulation through standardisation New York, NY Welding Research Council 2010 Welding research abroad LVI 09 18 21 2016-02-19 OPUS4-23874 Zeitschriftenartikel Heinze, Christoph; Schwenk, Christopher; Rethmeier, Michael Influences of mesh density and transformation behavior on the result quality of numerical calculation of welding induced distortion Welding simulation is a powerful, cost-efficient tool to predict welding induced distortion. Nevertheless, effects on calculation result quality are often unknown, thus, sensitivity analyses should be performed to evaluate the influences of certain parameters on distortion development. In the present paper, a single-layer gas metal arc (GMA) weld of 5 mm thick structural steel S355J2+N is experimentally and numerically investigated. Subsequent to welding, the numerical modeling begins with a mesh analysis based on modal analyses. Hereby, the influence of different coarsening methods and element edge length (EEL) in welding direction on the deformation behavior or the stiffness of the discrete geometry is the focus of the analysis. Secondly, phase transformations in structural steels such as S355J2+N are decisive for final product properties. The sensitivity of welding-induced distortion is examined regarding different continuous cooling transformation (CCT) diagrams for S355J2+N. The present investigations deal with different relevant influences on numerical calculation of welding-induced distortion. The quality and quantity of these effects are clarified based on the experimental and numerical set-up employed. Consequently, prediction of welding-induced distortion is possible and potential for pre-production optimization is present. Amsterdam [u.a.] Elsevier 2011 Simulation modelling practice and theory 19 9 1847 1859 10.1016/j.simpat.2011.05.001 2016-02-19 OPUS4-24088 Beitrag zu einem Tagungsband Perret, William; Alber, U.; Schwenk, Christopher; Rethmeier, Michael Wieland, H.-J. Efficient welding simulation of an automotive sheet metal assembly Fusion welding is widely used in the automotive industry to join metal structures. It is well-known that distortions and residual stresses occur during and after the welding process. Many procedures exist to decrease these negative heat effects of welding, but are often coupled with highly cost intensive experiments. The implementation of a welding Simulation tool to reduce this very expensive experimental procedures is therefore of high interest. Despite the fact that the automotive industry is a key sector for Simulation procedures, welding Simulation Software is nevertheless not yet widely implemented. This is mainly due to the complexity of the Simulation tools requiring expert users and the resulting high time to Solution. In this study, a new fast thermo-mechanical Simulation of a complex and large laser beam welded automotive sheet metal assembly with several non linear welds is simulated. Assumptions and simplifications of the complex physical welding phenomenon, which are made to keep the computational cost and the complexity of the Simulation in an industrial frame, are discussed. The calibration time of the phenomenological heat source model has been optimized with a very fast analytical thermal model and the resulting simulated temperature fields match perfectly with the measured ones. Additionally, the user experience and the time-to-solution are kept within a reasonable time frame for arr industrial environment. All Simulation results are validated with experimental results. Stahleisen Steel Institute VDEh 2011 SCT2011 - 3rd International conference on steels in cars and trucks - Future trends in steel development, processing technologies and applications 978-3-514-00783-3 SCT2011 - 3rd International conference on steels in cars and trucks Salzburg, Austria 05.06.2011 09.05.2011 704 713 2016-02-19 OPUS4-23984 Beitrag zu einem Tagungsband Chen, Ji; Schwenk, Christopher; Wu, Chuan Song; Rethmeier, Michael Prediction of weld pool shape and influence of joint preparation angle for new gas metal arc welding processes This article studies the three dimensional transient weld pool dynamics and the influence of joint preparation angle on welding of low carbon structural steel plates using the ForceArc® process. ForceArc is a new gas metal arc welding technology which allows adequate fusion and penetration with a smaller V groove angle. This enhances welding efficiency significantly because of reduction of layers and low material consumption. The deformation of the weld bead is calculated with an accurate coupling of the heat transfer with fluid flow through continuity, momentum and the energy equations combined with the effect of droplet impingement, gravity, electromagnetic force, buoyancy, drag forces and surface tension force (Marangoni effect). Four different angles of V groove are employed with the same welding parameters and their influence on the weld pool behavior and weld bead geometry is calculated and analyzed, to allow subsequent calculations of residual stress and distortion of the workpiece. Such a simulation is an effective way to study welding processes because the influence of all the welding parameters can be analyzed separately with respect to thermal cycle, weld bead formation, and the microstructure of the weld. Good agreement is shown between the predicted and experimentally determined weld bead dimensions. It was found that with a larger groove angle, the penetration depth increases. Furthermore, a higher wire feeding rate is needed to fill the larger groove. The model presented can be used for further analyses of GMAW processes as well as input data for the numerical calculation of welding induced residual stresses and distortions using Computational Weld Mechanics CWM. Institute for the Joining of Materials 2011 JOM-16 - 16th International conference on the joining of materials (Proceedings) 87-89582-19-5 JOM-16 - 16th International Conference on the Joining of Materials Tisvildeleje, Denmark 10.05.2011 13.05.2011 JOM 7 / J15 1 13 2016-02-19 OPUS4-24164 Zeitschriftenartikel Karkhin, Victor; Pittner, Andreas; Schwenk, Christopher; Rethmeier, Michael Simulation of inverse heat conduction problems in fusion welding with extended analytical heat source models The paper presents bounded volume heat sources and the corresponding functional-analytical expressions for the temperature field. The power density distributions considered here are normal, exponential and parabolic. The sources model real heat sources like the welding arc, laser beam, electron beam, etc., the convection in the weld pool as well as the latent heat due to fusion and solidification. The parameters of the heat source models are unknown a priori and have to be evaluated by solving an inverse heat conduction problem. The functional-analytical technique for calculating 3D temperature fields in butt welding is developed. The proposed technique makes it possible to reduce considerably the total time for data input and solution. It is demonstrated with an example of laser beam welding of steel plates. Secaucus, N.J. Springer 2011 Frontiers of materials science 5 2 119 125 10.1007/s11706-011-0137-1 2016-02-19 OPUS4-24165 Beitrag zu einem Tagungsband Karkhin, Victor; Pittner, Andreas; Schwenk, Christopher; Rethmeier, Michael Halmoy, E. Simulation of the temperature field in laser beam welding by inverse technique This paper presents volume heat sources and the corresponding functional analytical Solutions for the transient temperature field. The considered energy distributions are normal, exponential and parabolic. The method follows the common approach in Computational Welding Mechanics (CWM) to account for the physics of the welding process and the resulting temperature field by phenomenological models for heat conduction. Therefore, the used heat source models are apparent heat sources that incorporate the real heat input as well as the fluid flow in the weld pool and the latent heat connected with phase transformations. The heat source models provide welding characteristics like thermal cycle and Fusion line in the cross section within short computational time. Consequently, inverse techniques on basis of optimisation algorithms enable the adaptation of the models to the experimental data efficiently. Furthermore, the direct evaluation of the energy distribution for the experimental fusion line in the cross section is demonstrated which enhances the numerical optimisation by reducing the number of unknown model Parameters and providing a reasonable initial guess within the model parameter space. The proposed temperature field models are validated with real laser beam welding experiments. Norwegian university of science and technology 2011 13th Conference on laser materials processing in the nordic countries 13th Conference on laser materials processing in the nordic countries Trondheim, Norway 27.06.2011 29.06.2011 223 234 2016-02-19 OPUS4-23350 Forschungsbericht Rethmeier, Michael; Schwenk, Christopher; Heinze, Christoph Optimierung von Verzug und Eigenspannungen beim Schweißen dickwandiger Bauteile Die Schweißsimulation dickwandiger Bauteile stellt aufgrund der erhöhten Komplexität der thermophysikalischen und thermomechanischen Vorgänge beim Mehrlagenschweißen hohe Anforderungen an kommerziell verfügbare Schweißsimulationssoftware. Das umfasst die während des Fügeprozesses induzierten Verzüge und Eigenspannungen in das gefertigte Bauteil, welche zur Beurteilung der Fertigungsqualität von großer Bedeutung sind. Gerade in dickwandigen Bauteilen ist der Spannungszustand sowohl bedingt durch die konstruktive Steifigkeit der einzelnen Bauteile sowie der gesamten Baugruppe als auch aufgrund zusätzlicher externer Einspannvorrichtungen bei der Fertigung überaus komplex. Hinzu kommen bei Werkstoffen mit Phasenumwandlung noch die metallurgisch verursachten Spannungszustände und bei mehrlagig ausgeführten Schweißverbindungen die wiederholte thermische und umwandlungsbedingte Spannungsausbildung, so dass eine überschlägige Abschätzung des gesamten Verformungs- und Spannungszustandes auch für Experten in der Regel nicht mehr möglich ist. Die vorherrschenden Verformungen und Spannungen bestimmen jedoch maßgeblich die Eigenbeanspruchung der Schweißkonstruktion und damit deren Belastbarkeit im Betrieb. Eine genaue Kenntnis dieser Daten würde wertvolle Informationen zur Qualitätsoptimierung des Endproduktes liefern. Düsseldorf Verlag und Vertriebsgesellschaft mbH Forschungsvereinigung Stahlanwendung e.V. (FOSTA) 2011 Forschung für die Praxis P 784 3-937567-98-4 1 160 2016-02-19 OPUS4-23357 Zeitschriftenartikel Heinze, Christoph; Kromm, Arne; Schwenk, Christopher; Kannengießer, Thomas; Rethmeier, Michael Welding residual stresses depending on solid-state transformation behaviour studied by numerical and experimental methods The development of high-strength structural steels with yield strengths up to 1000 MPa results in the requirement of suitable filler materials for welding. Recently designed low transformation temperature (LTT) alloys offer appropriate strength. The martensitic phase transformation during welding induces compressive residual stress in the weld zone. Therefore, the mechanical properties of welded joints can be improved. The present paper illustrates numerical simulation of the residual stresses in LTT-welds taking into account the effect of varying Ms/Mf-temperatures, and therefore different retained austenite contents, on the residual stresses. Residual stress distributions measured by synchrotron diffraction are taken as evaluation basis. A numerical model for the simulation of transformation affected welds is established and can be used for identification of appropriate Ms-temperatures considering the content of retained austenite. Aedermannsdorf, Switzerland Trans Tech Publications 2011 Materials science forum 681 85 90 10.4028/www.scientific.net/MSF.681.85 2016-02-19 OPUS4-23382 Beitrag zu einem Sammelband Karkhin, V.A.; Pittner, Andreas; Schwenk, Christopher; Rethmeier, Michael Makhnenko, V.I. Heat source models in simulation of heat flow in fusion welding Kiev, Ukraine E.O. Paton Electric Welding Institute of the NAS of Ukraine 2010 5th International Conference - Mathematical modelling and information technologies in welding and related processes (Proceedings) 978-966-8872-15-0 5th International Conference - Mathematical modelling and information technologies in welding and related processes vil. Katsiveli, Crimea, Ukraine 2010-05-25 2010-05-28 56 60 2016-02-19 OPUS4-23324 Vortrag Schwenk, Christopher Schweißsimulation an der BAM und am IPK 2011 Veranstaltung für Industrievertreter der Fa. ZF Friedrichshafen, Präsentation von aktuellen Projekten und Forschungsergebnissen Veranstaltung für Industrievertreter der Fa. ZF Friedrichshafen, Präsentation von aktuellen Projekten und Forschungsergebnissen Friedrichshafen, Germany 2011-02-22 2016-02-19 OPUS4-23673 Zeitschriftenartikel Schwenk, Christopher; Tikhomirov, D.; Diether, T. Erste Spezifikation für die numerische Schweißsimulation - Normenausschuss Schweißtechnik (NAS) im DIN - DIN SPEC 32534-1:2011-03 "Numerische Schweißsimulation - Durchführung und Dokumentation - Teil 1: Übersicht" Mit Ausgabedatum März 2011 ist die Spezifikation DIN SPEC 32534-1 erschienen. Die Spezifikation wurde im DIN/DVS-Gemeinschaftsausschuss NA 092-00-29 AA „Schweißsimulation (DVS AG I 2.1)" des Normenausschusses Schweißtechnik (NAS) im DIN in Zusammenarbeit mit dem Ausschuss für Technik (AfT) im DVS - Deutscher Verband für Schweißen und verwandte Verfahren e. V. nach dem Vornormverfahren erarbeitet. Berlin Beuth Deutsches Institut für Normung 2011 DIN-Mitteilungen + Elektronorm 5 129 130 2016-02-19 OPUS4-23627 Beitrag zu einem Tagungsband Thater, R.; Perret, William; Schwenk, Christopher; Alber, U.; Rethmeier, Michael Vollertsen, F. Different modeling approaches for efficient distortion calculation of an automotive assembly In contrast to other simulation fields like forming simulation, welding simulation is still not widely used in industrial environments. A high user expertise, a high time-to-solution and the result accuracy are the most important problems that hinder its extensively application. Different modeling approaches influence these aspects and an analysis of their implementation is of interest especially for the automotive industry as a key user for production Simulation. Bremen Bremer Institut für angewandte Strahltechnik (BIAS) 2011 International workshop on thermal forming and welding distortion - IWOTE' 11 (Proceedings) 978-3-933762-35-1 International workshop on thermal forming and welding distortion - IWOTE´ 11 Bremen, Germany 06.04.2011 07.04.2011 279 291 2016-02-19 OPUS4-18614 Beitrag zu einem Sammelband Pittner, Andreas; Schwenk, Christopher; Rethmeier, Michael; Weiß, D. Hirata, Yoshinori; Manabu Tanaka, Automated generation of temperature fields for numerical welding simulation Kyoto Japan Welding Society 2008 Proceedings of the 8th International Welding Symposium - Innovations in Welding and Joining for a New Era in Manufacturing 8th International Welding Symposium - Innovations in Welding and Joining for a New Era in Manufacturing Kyoto, Japan 2008-11-16 2008-11-18 158 2016-02-19 OPUS4-19085 Vortrag Schwenk, Christopher Eintwurf einer Richtlinie zur strukturierten Vorgehensweise bei der Durchführung, Auswertung und Ergebnisdarstellung einer numerischen Simulation schweißbedingter Verzüge und Eigenspannungen 2009 Sitzung des NAS-Beirates Sitzung des NAS-Beirates Berlin, Germany 2009-03-02 2016-02-19 OPUS4-23008 Beitrag zu einem Sammelband Caron, J.; Heinze, Christoph; Schwenk, Christopher; Rethmeier, Michael; Babu, S. S.; Lippold, J. Cerjak, H.; Enzinger, N. Sensitivity analysis of martensite transformation temperatures with respect to numerical calculation of welding-induced residual stresses Verlag der Technischen Universität Graz 2010 Mathematical modelling of weld phenomena 9 978-3-85125-127-2 215 238 2016-02-19 OPUS4-59606 Forschungsbericht Schwenk, Christopher; Perret, William Abschlussbericht zur Übersicht aktueller Software im Bereich Schweißsimulation Das Ziel der vorliegenden Vorstudie ist es, die grundsätzlichen Anforderungen, Funktionen und Möglichkeiten vorhandener Software zur Simulation schweißbedingter Phänomene (Prozess-, Struktur- und Werkstoffsimulation) zu erarbeiten und gegenüberzustellen. Die notwendigen Eingabedaten, die vorausgesetzte Anwendererfahrung, sowie die Systemanforderungen und der Rechenzeitbedarf werden für sowohl kommerziell erhältliche als auch zur Zeit noch rein in der Forschung angewandte Programme berücksichtigt. Nach Aufarbeitung des heutigen Kenntnisstandes der Schweißsimulation wird aktuell verfügbare Software diskutiert. Diese Programme lassen sich in Anlehnung an Radaj in drei Teilbereiche (Software für Struktursimulation, Prozesssimulation und Werkstoffsimulation) unterteilen. Schließlich wird auf notwendige Eingabedaten, hier vor Allem auf die Werkstoffkennwerte, eingegangen. Da die quantitative Aussagekraft der Simulationsergebnisse gewährleistet werden muss, ist eine umfassende Prüfung der Plausibilität und der Genauigkeit der experimentell bestimmten Werkstoffkennwerte notwendig. Berlin Bundesanstalt für Materialforschung und -prüfung (BAM) 2009 1 64 2015-12-31