The plane strain compression test, an alternative to large strain hardening characterization

Abstract

Abstract. Large strain characterization of sheet metals has become increasingly important with the generalization of advanced high strength steels, for which the tensile test provides data over a very reduced strain range. Among the numerous alternative characterization tests, the plane strain compression test (PSCT) requires a small amount of material and classical testing machine and acquisition. PSCT was mainly used for hot forming characterization, but recently it has been proved sufficiently accurate for application in cold metal forming. The aim of this work is to provide an in-depth validation of the PSCT by means of the finite element method. When converting the PSCT force-displacement curve into a stress-strain curve (flow curve), several analytical corrections are applied. The FE simulation of the test was used in order to validate these correction terms and their hypotheses. The originality of the approach is the design of a sequence of test configurations which allow for the individual validation of each and every one of the correction terms concerning the effect of: yield surface; friction; variation of sample width; variation of contact zone length; edge effects. The FE simulations showed that the analytical exploitation of the PSCT provides a very good accuracy. They help identifying the most suitable correction to consider the effects of yield surface shape, friction, edge effects. The traditional correction of the sample width as well as the more recent correction of the effective tool width were validated. The results show that the PSCT provides accurate flow curves and designate the best analytical expressions to be used.