In-plane Biaxial Compression Test on 780MPa Cold Rolled Sheet Steel

Abstract

Accuracy in finite element simulation (FE-simulation) of press-forming has improved through sophisticated material modelling partly by using data of various experiments such as uniaxial compression test, biaxial tension test, and in-plane cyclic loading test. However, biaxial compression test on sheet material has never been reported due to difficulty in buckling suppression, and difference between material behavior under biaxial tension and that under compression has not been discussed yet. In this paper, biaxial compression test on sheet material with special tools suppressing buckling and a specimen shape to achieve uniform deformation in measurement area is proposed mainly based on FE-simulation. The special tool has a urethane plate at the place where the tool contact with the measurement area of a specimen to prevent damage of strain gauges. Absolute values of compressive stress at a plastic work measured by the biaxial compression test were larger than tensile stresses at the same plastic work measured by biaxial tension test: the similar results observed in uniaxial tension and compression tests known as stress differential (SD) effect.