Fine-blanking process simulation by rigid viscous-plastic FEM coupled with void damage

In the present paper, a 3-D rigid visco-plastic finite-element method coupled with void damage was developed for analyzing the fine-blanking process with an incremental implicit algorithm. Based on the Gurson-Tvergaard-Needleman plastic potential equation and the orthogonal rules, the effect of void volume fraction was introduced into the material constitutive law to document the ductile damage of the deformed material. A principle of variation of rigid visco-plastic material was presented considering both the shear work and the work caused by the change of volume. This proposed principle reveals both the effects of equivalent stress and hydrostatic pressure. The related FEM equations coupled with void damage based on this principle of variation were presented and the void damage in form of void volume fraction was applied to denote the ductile fracture in the blanking process. Based on the obtained system, the fine blanking process was simulated and the onset of the micro-crack of the sheet wais predicted. Furthermore, the influence of the studied work-piece shape on the deformation process was also discussed.

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