Simulation of Electromagnetic Forming of a Cross-Shaped Cup by Means of a Viscoplasticity Model Coupled with Damage at Finite Strains

Abstract:

In the field of sheet metal forming traditional forming processes are used. However, a quasi-static forming process combined with a high speed forming process can enhance the forming limits of a single one. In this paper, the investigation of the process chain quasi-static deep drawing – electromagnetic forming by means of a new coupled damage-viscoplasticity model for large deformations is performed. The finite strain constitutive model, used in the finite element simulation combines nonlinear kinematic and isotropic hardening and is derived in a thermodynamically consistent setting. The anisotropic viscoplastic model is based on the multiplicative decomposition of the deformation gradient in the context of hyperelasticity. The kinematic hardening component represents a continuum extension of the classical rheological model of Armstrong–Frederick kinematic hardening. Hill-type plastic anisotropy is modelled by expressing the yield surface as a function of second-order structure tensors as additional tensor-valued arguments. The coupling of damage and plasticity is carried out in a constitutive manner according to the effective stress concept. The constitutive equations of the material model are integrated in an explicit manner and implemented as a user material subroutine in the commercial finite element package of LS-Dyna with the electromagnetical modul. Aim of the work is to show the increasing formability of the sheet by combining quasi-static deep drawing processes with high speed electromagnetic forming process.

• Periodical: Key Engineering Materials (Volumes 554-557)
• Pages: 2363-2368
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.554-557.2363
• Online since: June 2013
• Authors: Yalin Kiliclar, O. Koray Demir, Ivaylo N. Vladimirov, Lukas Kwiatkowski, Stefanie Reese, A. Erman Tekkaya
• Keywords: Damage, Deep Drawing, Materials Modelling, Viscoplasticity

References

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DOI: 10.4028/www.scientific.net/kem.554-557.2363