PSI - Issue 2_A

Florian Gutknecht et al. / Procedia Structural Integrity 2 (2016) 1700–1707 Gutknecht et al. / Structural Integrity Procedia 00 (2016) 000–000

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does not distinguish between positive and negative triaxiality shows a completely different evolution of damage and thus leads to a crack path which is not observed in reality. 5. Conclusion A fully-coupled elasto-plastic Lemaitre-type damage model is applied to a 2D plane strain process simulation of shear cutting with an open-cut. Material parameters are identified with a time-efficient approach. Complementary experiments of the process are conducted to validate the model. The findings of this work can be summarized as:  The application of an enhanced Lemaitre damage model enables accurate prediction of force and cutting surface quality for shear cutting with an open-cut.  An objective evaluation criterion has been presented for determination of transition from burnish to fracture  Comparison of open-cut and closed-cut simulation have revealed that the stress states for both processes are significantly different. The open-cut process is much more shear dominated than the closed-cut.  Nevertheless analysis of the triaxiality indicates that negative triaxiality still occurs. Therefore it needs to be taken into account correctly. The applied Lemaitre model distinguishes between the effect of positive and negative stresses on damage evolution Further investigation are necessary to validate these results for different process parameters (e.g. clearance, sheet FS acknowledges financial support of the IGF project 17791 N of the Research Association for Steel Application, FOSTA, Sohnstraße 65, 40237 Düsseldorf, funded by AiF in the context of the program for support of Industrial Collective Research and Development (IGF) by the Federal Ministry of Economic Affairs and Energy on the basis of a decision by the German Bundestag. All other authors appreciate financial support from the German Research Foundation (DFG) in the project DFG 1 Te 508/37-1 and Vo 1487/2-1. Both projects are embedded in the Research-Cluster PAK 678/0 “Dry Shear Cutting of Metal Laminated Composite Material” supported by DFG and Arbeitsgemeinschaft industrieller Forschungsvereinigungen “Otto von Guericke” e.V. (AiF). References Abaqus 6.11 Analysis User’s Manual, Vol. 5, Dassault Systèmes Simulia Corp. (2011) Bao, Y., Wierzbicki, T., 2004. On fracture locus in the equivalent strain and stress triaxiality space. In: Int. J. Mech. Sci. 46(1), 81-98 Brosius, A., Yin, Q., Güner, A., Tekkaya, A.E., 2011. A New Shear Test for Sheet Metal Characterization. In: steel research international 82, 323– 328. Dalloz, A., Besson, J., Gourgues-Lorenzon, A.-F., Sturel, T., Pineau, A., 2009. Effect of shear cutting on ductility of a dual phase steel. In: Eng. Frac. Mech. 76, 1411-1424 Gutknecht, F., Steinbach, F., Clausmeyer, T., Tekkaya, A.E, 2015. Advanced material model for shear cutting of metal sheets. In: Proceedings of the XIII COMPLAS, Barcelona: CIMNE, 2015, 170-181. Lemaitre, J., 1971. Evaluation of dissipation and damage in metals. Proceedings of I.C.M. 1. Kyoto, Japan. Lemaitre, J., Desmorat, R., 2005. Engineering Damage Mechanics, Springer Verlag. Sasada, M., Shimura, K., Aoki, I., 2006. Coefficient of Friction between Tool and Material in Shearing. In: JSME International Journal Series C Mechanical Systems, Machine Elements and Manufacturing 49, 1171-1178. Soyarslan, C., Tekkaya, A.E., 2010. A damage coupled orthotropic finite plasticity model for sheet metal forming: CDM approach. In: Comp. Mat. Sci. 48(1), 150-165. thickness, worn tools). Acknowledgements