Numerical investigations on sheet metal blanking with high speed deformation

The ferromagnetic sheet metal blanking is widely used for the manufacturing of rotating electrical machines. However, the optimization of the designed machines depends on full understanding of the shearing process. The material mechanical state and magnetic properties near the cut edge depend on various parameters like geometric configuration (shape of the tools, punch blade radius), clearance, frictional contact at the interfaces and the punch speed. Several studies of the blanking process have been proposed to assess the influence of these parameters, but only a few are concerned with the punch velocity. In this paper we use a rate dependent constitutive model for the blanking process investigation to improve the accuracy of the predictions. A 0.65 mm thickness sheet of a non-oriented full-process FeSi (3 wt.%) steel is used. The material testing and the characterization are carried out in order to fit the constitutive model parameters to the experimental data. Classical tensile tests and video-tensile tests are combined to establish the sheet metal constitutive law. The identified model is, then, used for numerical simulations (which are performed using ABAQUS/Explicit software) of various blanking tests: the clearance is ranging from 3.8% to 23%, punch velocity of 23 mm/s and 123 mm/s. In order to validate this work the numerical results obtained are compared to the measurement. The comparisons relate to the punch force and the punch penetration at fracture that are affected by the clearance and the strain rate. (C) 2009 Elsevier Ltd. All rights reserved.