Design and Development of a Laboratory Formability Test for Thin Sheets with Numerical Simulation

The simulation of manufacturing processes has a large appeal for improving the performance of the Computed Aided Engineering in several industries using extensively casting, welding, forging and deep drawing. The numerical simulation of deep drawing processes became just recently a tool, as a consequence of the development new user friendly 3D Finite Element Explicit Time Integration Techinique codes for the improved workstations and supercomputers. Although the 3D Finite Element Implicit Time Integration Techinique are the best methods to analyse the quasi-static formulation, the computer time and memory size required are too large.

This paper is focused on the application of the numerical simulation with the finite element explicit code PAM-STAMP™ to design a formability test for coated thin steel sheets. The tooling and the blank geometries are selected to induce a constant plane strain path leading to a localized necking. The most practical test result is precisely the Limiting Dome Heigth at the beginning of necking. This code has been applied to simulate the effects of some relevant tooling geometrical parameters on the test main result, the Limiting Dome Heigth, but provides also the thickness distribution. The code has been applied with three different materials, with typical mechanical properties characteristics of thin coated steel sheets. The same tooling geometry has been used to simulate the springback of the harder material, because there is a growing industrial concern in weigth saving, and this is obtained using high strength steel.