Abstract: A high precision finite-element model of eight-node quadrangle element is developed for plane-strain section analysis with die's section curve described by NURBS to make contact judgement. In order to get the prefect analysis result of sheet metal stamping forming in a little computing time, the elastic-plastic large deformation finite element method formulation based on virtual workrate principle is used. The validity, feasibility and high efficiency of the section analysis technology are testified with the analytic and experimental result of cylindrical punch stretch/draw process and engine oil-sump draw process.

Key words: Contact judgement, Eight-node quadrangle element, Plane-strain, Section analysis