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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: finished

Last Update: 19.10.2020


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.; Tekkaya, A.; Gerstein, G.; Nürnberger, F.: Strain path dependency in incremental sheet-bulk metal forming. In: International Journal of Material Forming, (2020), DOI: 10.1007/s12289-020-01537-0, published
    • Clausmeyer, T.; Gutknecht, F.; Gerstein, G.; Nürnberger, F.: Testing of formed gear wheels at quasi-static and elevated strain rates. In: 23rd International Conference on Material Forming (Edt.): Procedia Manufacturing, 47(2020), Elsevier, pp. 623-628


    • Clausmeyer, T.; Nürnberger, F.; Gutknecht, F.; Isik, K.; Besserer, H.; Gerstein, G.; Wernicke, S.; Schulte, R.; Tekkaya, A.; Maier, H.: Analyse und Modellierung von Schädigung und Versagen in der Blechmassivumformung. In: 4. Workshop Blechmassivumformung : Umformtechnische Herstellung von komplexen Funktionsbauteilen mit Nebenformelementen aus Feinblechen, (2019), FAU University Press, submitted
    • Gutknecht, F.; , .; 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: Yannis Korkolis, Brad Kinsey, Marko Knezevic, and Nikhil Padhye (Edtr.) (Edt.): Proceedings of NUMIFORM 2019: The 13th International Conference on Numerical Methods in Industrial Forming Processes, (2019), pp. 123-126
    • 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
    • Bryukhanov, A.; Gerstein, G.; Volchok, N.; 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), Springer, pp. 506-512
    • Gutknecht, F.; Clausmeyer, T.: Analysis of strain-path change indicator for application in sheet-bulk metal forming. In: Forming Technology Forum 2019, (2019), published on CD


    • Gutknecht, F.; Clausmeyer, T.; Wernicke, S.; Gies, S.; Tekkaya, A.: Vorstellung eines Lastpfadindikators für die Blechmassivumformung. In: 19. Simufact RoundTable, 17.05.2018 in Marbung, (2018), published
    • Isik, K.: Modelling and characterization of damage and fracture in sheet-bulk metal forming. In: Dortmunder Umformtechnik, 101(2018), Shaker Verlag, published
    • 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: 17th International Conference on Metal Forming (Edt.): Procedia Manufacturing, 15(2018), pp. 527-534
    • Isik, K.; Yoshida, Y.; Chen, L.; Clausmeyer, T.; Tekkaya, A.: Modelling of the blanking process of high-carbon steel using Lemaitre damage model. In: Comptes Rendus Mécanique, 346(2018)8, Elsevier, pp. 770-778


    • Gerstein, G.; Isik, K.; Sieczkarek, P.; Ewerth, J.; Tekkaya, A.; Clausmeyer, T.; Nürnberger, F.: MICROSTRUCTURAL CHARACTERIZATION AND SIMULATION OF DAMAGE FOR GEARED SHEET COMPONENTS. In: Journal of Physics: Conference Series 36th IDDRG Conference - Materials Modelling and Testing for Sheet Metal Forming 2–6 July 2017, Munich, Germany, 896(2017), published
    • Gerstein, G.; Clausmeyer, T.; Gutknecht, F.; Tekkaya, A.; Nürnberger, F.: Analysis of dislocaton structures in ferritic and dual phase steels regarding continuous and discontinuous loading path. In: The Minerals, Metals & Materials Society (Edt.): TMS 2017 146th Annual Meeting & Exhibition Supplemental Proceedings, (2017), Springer, published
    • Gutknecht, F.; Isik, K.; Clausmeyer, T.; Tekkaya, A.: Comparison of gurson and lemaitre model in the context of blanking simulation of high stregth steel. In: E. Onate, D.R.J. Owen, M. Chiumenti (Edt.): Proceedings of XIV International Conference on Computational Plasticity, (2017), published
    • Gerstein, G.; Besserer, H.; Nürnberger, F.; Luis Antonio Barrales-Mora; Lasar S. Shvindlerman; Yuri Estrin; Maier, H.: Formation and growth of voids in dual-phase steel at mircrsocale and nanoscale level. In: Journal of Materials Science, 52(2017), Springer, pp. 4234-4243