In a previous work a numerical tool was presented which accurately predicted both process force and fracture initiation for blanking of a ferritic stainless steel in various blanking geometries. This approach was based on the finite element method, employing a rate-independent elasto-plastic constitutive model combined with a fracture criterion which accounts for the complete loading history. In the present investigation this work is extended with respect to rate-dependence by employing an elasto-viscoplastic constitutive model in combination with the previously postulated fracture criterion for ferritic stainless steel. Numerical predictions are compared to experimental data over a large range of process speeds. The rate-dependence of the process force is significant and accurately captured by the numerical simulations at speeds ranging from 0.001 to 10 mm/s. Both experiments and numerical simulations show no influence of punch velocity on fracture initiation.

Issue Section:
Technical Papers
Keywords:
manufacturing processes, ductile fracture, elastoplasticity, viscoplasticity, stress-strain relations, numerical analysis, stainless steel
Topics:
Blanking (Metalworking), Ductile fracture, Constitutive equations, Computer simulation, Stainless steel, Fracture (Materials), Fracture (Process)
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