Parameter identification and blanking simulations of DP1000 and Al6082-T6 using Lemaitre damage model

Abstract

This work provides numerical and experimental investigations of blanking process, where the shear-enhanced Lemaitre’s damage model is fully characterized and successfully applied in blanking process to predict the cutting force and cutting edge geometry under different blanking process parameters. Advanced high strength steel DP1000 and an aluminum alloy Al6082-T6 are selected for series of experiments. To obtain the damage parameters in Lemaitre’s damage model the flat rectangular notched specimens tensile test was conducted and the inverse parameter identification procedure was performed. For characterizing the crack closure parameter h in the shear enhanced Lemaitre’s damage model, an in-plane torsion test with novel specimen design was conducted. The finite element model (FEM) of this test was established with the minimum mesh size of 0.01 mm which was consistent with the minimum mesh size in the shear zone of the FEM for blanking process simulation. The longitudinal strain distributions of four kinds of initial notch radius or central-hole specimen were measured and compared with simulation results to validate the FEMs for these four tests. Deformation analysis of blanking of a circular work piece also was performed under three clearances. The effects of blanking conditions on sheared part morphology were detected. Stress triaxiality distribution of the blank sheet was revealed taking advantage of the successfully established FEM. The availability of the testing method and the determination method of the parameters was investigated.

Keywords

Blanking / Lemaitre damage model / Stress triaxiality / Finite element model (FEM)