Fraunhofer-Institut für Produktionsanlagen und Konstruktionstechnik IPK

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  • Publication
  • Publication
    Different modeling approaches for efficient distortion calculation of an automotive assembly
    ( 2011)
    Thater, R.
    ;
    Perret, W.
    ;
    Schwenk, C.
    ;
    Alber, U.
    ;
    Rethmeier, M.
    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. In this study a MIG welded aluminum assembly from the automotive industry is investigated. Experimental and numerical methods are performed. On the experimental side, temperature cycles are obtained with thermocouples and transient distortion fields are measured using a 3D optical analysis system. On the numerical side, threedimensional nonlinear welding simulations are performed using the welding simulation software simufact.welding to obtain the transient distortion field of the investigated industrial assembly. Several modeling approaches are considered and are discussed with respect to the time-to-solution (modeling effort and the calculation time) and the result accuracy. Finally, a FE model with a good result accuracy and a reasonable calculation time for an industrial application is presented.
  • Publication
    Simulation of welding temperature field in laser beam welding by inverse techniques
    ( 2011)
    Karkhin, V.A.
    ;
    Pittner, A.
    ;
    Schwenk, C.
    ;
    Rethmeier, M.
  • Publication
    Efficient welding simulation of an automotive sheet metal assembly
    ( 2011)
    Perret, W.
    ;
    Thater, R.
    ;
    Alber, U.
    ;
    Schwenk, C.
    ;
    Rethmeier, M.
  • Publication
  • Publication
    Welding residual stresses depending on solid-state transformation behaviour studied by numerical and experimental methods
    ( 2011)
    Heinze, C.
    ;
    Kromm, A.
    ;
    Schwenk, C.
    ;
    Kannengiesser, T.
    ;
    Rethmeier, M.
    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 transforma tion affected welds is established and can be used for identification of appropriate Ms-temperatures considering the content of retained austenite.
  • Publication
    Industrial application of welding temperature field and distortion visualization using FEA
    ( 2010)
    Thater, R.
    ;
    Perret, W.
    ;
    Schwenk, C.
    ;
    Alber, U.
    ;
    Rethmeier, M.
    Welding simulation offers with its holistic visualization of physical phenomena occurring during and after the welding process, like temperature and distortions, the opportunity to clearly identify the mechanisms responsible for the global deformations of welded parts. With this information, a target-oriented adaption of the welding parameters like welding sequence and clamping conditions is possible in order to minimize the welding distortions, whereby the required number of experimental iterations can be significantly reduced. Nevertheless, the industrial application of welding simulation is not yet established widely because of reservations regarding the computation costs and the result accuracy. The aim of this study is to show the applicability of the welding simulation within an ind ustrial environment and to com-pare its visualization capabilities and implementation to experimental procedures. For this purpose a welded assembly from the automotive industry has been simulated and compared with experimental data. The calculation is in a reasonable time frame and the characteristics of welding distortions are reproduced by the simulation in detail. Finally, it is shown that the numerical visualization with its high flexibility compared to experimental visualization has a great potential as part of a target-oriented distortion optimization to reduce experimental iteration steps.