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C4 - Microstructural Analysis - FEA

Analysis of Load History Dependent Evolution of Damage and Microstructure for the Numerical Design of Sheet-bulk Metal Forming Processes

Project Status: Active

Last Update: 19.07.2019


The aim of this project is the numerical failure prediction in sheet-bulk forming processes based on coupled damage models, which are motivated and validated by microstructural analysis. This serves the purpose to predict the remaining formability and a safe process window for complex multi-step sheet-bulk forming processes. Hence minor goals are following, like the characterization and modelling of anisotropic hardening, characterization and modelling of strain rate dependencies and the determination of the local loose in stiffness of the workpiece.

Material models developed in the first and second stage to model kinematic hardening, shall be modified to model hardening phenomena like cross-hardening and hardening stagnation, which can be observed for continuous and discontinuous loading path changes in DC04 and DP600. These advanced models are used by TP A4 to adapt process routes of ISBMF in such a manner that locally wanted hardening effects occur. The anisotropic hardening model is combined with a criterion for ductile damage to take into account the impact of load history dependent hardening and evolution of pore structure on fatigue.

The strain rate dependent hardening and fatigue behavior of DC04 and DP600 is to be captured experimentally in a range between 0.001 1/s and 500 1/s. Hence, the developed Gurson- and Lemaitre-based failure models have to be extended with a strain rate dependency to predict the strain rate dependent evolution of damage in the manufacturing as well as the usage. The observed influence of higher strain rates on the evolution of pore structure has to be taken into account for the formulation of the enhanced models.

For a reasonable characterization of initial damage resulting from sheet-bulk metal forming processes and damage due to abrupt dynamic loads in the stage of usage, the resonance method, which was qualified/verified in the second stage, is to be adapted to reduced material volumes, to determine macroscopic damage in predefined areas even for short-term measurements.

For the aim of determining above-mentioned cross-hardening effect at large strains, the Bulge-Torsion-Test has been developed at the IUL. The combination of bulge test and torsion test allows an orthogonal strain-path change at plastic strains greater than 0.5. This approach makes it possible to characterize cross-hardening at strains typical for sheet-bulk metal forming.



Working Groups



    • Wernicke, S.; Hahn, M.; Gerstein, G.; Nürnberger, F.; Tekkaya, A.: Strain path dependency in incremental sheet-bulk metal forming. In: International Journal of Material Forming, (2020), Paris: Springer-Verlag France SAS, part of Springer Nature, published


    • Bryukhanova, A. A.; Gerstein, G.; Volchok, N. A.; Bryukhanova, Z. A.; Nürnberger, F.: Effect of Low-Temperature Annealings on the Change in the Level of Microdamage of Sheets of the Dual DP-600 Steel. In: Physics of Metals and Metallography, 120(2019)5, pp. 506-512
    • Clausmeyer, T.; Nürnberger, F.; Gutknecht, F.; Isik, K.; Besserer, H.; Gerstein, G.; Wernicke, S.; Schulte, R.; Tekkaya, A.; Merklein, M.; Maier, H.: Analyse und Modellierung von Schädigung und Versagen in der Blechmassivumformung. In: Merklein, M.; Behrens, B.-A.; Tekkaya, A. E. (Edt.): 4. Workshop Blechmassivumformung, (2019), Erlangen: FAU University Press, pp. 33-60
    • Gutknecht, F.; Vogel, M.; Schulte, R.; Merklein, M.; Rosenbusch, D.; Koch, S.; Hübner, S.; Behrens, B.; Tekkaya, A.; Clausmeyer, T.: Comparison of strain-path indicators for analysis of processes in sheet-bulk metal forming. In: Proceedings of Numiform 2019, (2019), published
    • Gutknecht, F.; Clausmeyer, T.: Analysis of strain-path change indicator for application in sheet-bulk metal forming. In: Proceedings of Forming Technology Forum, (2019), published on CD


    • Gutknecht, F.; Gerstein, G.; Traphöner, H.; Clausmeyer, T.; Nürnberger, F.: Experimental setup to characterize flow-induced anisotropy of sheet metals. In: International Deep Drawing Research Group 37th Annual Conference (Edt.): IOP Conference Series: Materials Science and Engineering, 418(2018), IOP Publishing, published
    • Gerstein, G.; Briukhanov, A.; Gutknecht, F.; Volchok, N.; Clausmeyer, T.; Nürnberger, F.; Tekkaya, A.; Maier, H.: Evaluation of micro-damage by acoustic methods. In: Procedia Manufacturing, (2018)15, pp. 527-534
    • Isik, K.; Yoshida, Y.; Chen, L.; Clausmeyer, T.; Tekkaya, A. E.: Modelling of the blanking process of high-carbon steel using Lemaitre damage model. In: Comptes Rendus - Mecanique, 346(2018)8, Elsevier Masson SAS, pp. 770-778
    • Isik, K.: Modelling and characterization of damage and fracture in sheet-bulk metal forming. In: Prof. Dr.-Ing. M. Kleiner (Edt.): Dortmunder Umformtechnik, Dissertation, 101(2018), Aachen: Shaker Verlag, pp. 1-182


    • Gerstein, G.; Besserer, H.; Nürnberger, F.; Barrales-Mora, L. A.; Shvindlerman, L. S.; Estrin, Y.; Maier, H.: Formation and growth of voids in dual-phase steel at microscale and nanoscale levels. In: Journal of Materials Science, 52(2017)8, pp. 4234-4243
    • Gerstein, G.; Clausmeyer, T.; Gutknecht, F.; Tekkaya, A.; Nürnberger, F.: Analysis of dislocation structures in ferritic and dual phase steels regarding continuous and discontinuous loading paths. In: 146th Annual Meeting & Exhibition Supplemental Proceedings (Edt.): The Minerals, Metals & Materials Society TMS 2017, 146(2017), Cham, Switzerland: Springer, pp. 203-210
    • Gutknecht, F.; Isik, K.; Clausmeyer, T.; Tekkaya, A.: Comparison of Gurson and Lemaitre model in the context of blanking simulation of a high strength steel. In: 14th International Conference on Computational Plasticity - Fundamentals and Applications (COMPLAS), (2017), Barcelona, Spain, pp. 163-173
    • Gerstein, G.; Isik, K.; Gutknecht, F.; Sieczkarek, P.; Ewert, J.; Tekkaya, A.; Clausmeyer, T.; Nürnberger, F.: Microstructural characterization and simulation of damage for geared sheet components. In: 36th IDDRG Conference on Materials Modelling and Testing for Sheet Metal Forming (Edt.): Journal of Physics Conference Series, 896(2017), München, Deutschland, published
    • Gerstein, G.; Clausmeyer, T.; Isik, K.; Nürnberger, F.; Tekkaya, A.; Bruchanov, A.; Maier, H.: Experimental analysis of anisotropic damage in dual-phase steel by resonance measurement. In: International Journal of Damage Mechanics , 26(2017)8, pp. 1147-1169



      • 11.04.2018: Gutknecht, F.: Charakterisierung der Fließkurve mit dem gewölbten Torsionsversuch, Workshop Werkstoffcharakterisierung für die Umformtechnik, Fürth
      • 16.05.2018: Gutknecht, F.: Vorstellung eines Lastpfadindikators für die Blechmassivumformung, 19. Simufact RoundTable - Simulating Manufacturing, Marburg
      • 09.10.2018: Isik, K.: Modellierung und Charakterisierung von Schädigung und Bruch bei der Blechmassivumformung, Arbeitsgruppe Simulation des DVM-Arbeitskreises Bauteilsicherheit und Bruchmechanik, Dortmund