INVESTIGATION INTO TOOL SURFACE DESCRIPTION FOR FINITE-ELEMENT ANALYSIS OF 3-DIMENSIONAL SHEET-METAL FORMING PROCESSES

Abstract

A general method for the mathematical description of arbitrarily-shaped tool surfaces is proposed by introducing the parametric and non-parametric patch approaches. The cubic Ferguson patch is employed to describe the tool surface in the parametric patch approach and an efficient contact search algorithm is suggested to make this parametric patch approach more realistic for the FE analysis. The non-parametric patch approach introduces a cubic blending function as in the case of the parametric patch approach to allow C1 continuity. In the approach, an array of equi-spaced points is required to construct the whole tool surface. Computations are carried out for some complex sheet forming examples including actual auto-body panel to verify the validity and the robustness of the developed contact search algorithms.