Thermomechanical simulations of blanking process operated over a wide range of punch velocities

Abstract

A numerical model based on the finite element method has been developed to simulate the blanking process. Thanks to this model we analyse the influence of punch velocities during blanking on the quality of the sheared edge and the characteristic parameters governing the process (maximum punch force and displacement, temperature increase). In this model, inertia, viscous and thermal effects are properly considered by means of a unified thermomechanical framework. A full remeshing approach is adopted to overcome the high distortion of elements due to large deformations, prior to fracture. The material strain-rate sensitivity is introduced by means of an extension of elasto-viscoplastic constitutive equations for the large strain regime. The inertial effects are considered thanks to an implicit time integration scheme. Crack propagation during the process is tracked using the element deletion method driven by an uncoupled damage criterion. Finally, the coupled thermomechanical problem is solved by an isothermal staggered scheme. Experimental and numerical results are compared for the entire range of punch velocities under consideration. Good agreement between both results has been found.