Measurement and analysis of yield locus and work hardening characteristics of steel sheets wtih different r-values

Abstract

Biaxial tensile experiments of six kinds of steel sheet with different r-values are carried out using a servo-controlled biaxial tensile testing machine. Successive contours of plastic work in the biaxial stress space and the plastic strain rate vectors are precisely measured for linear loading paths. The measured data are compared with the theoretical predictions based on the Taylor–Bishop–Hill model with the full constraints and relaxed constraints assumptions using the experimentally determined crystallographic textures. Comparisons with the Hill quadratic and Hosford yield criteria are also made. It is found that (1) the TBH model with the full constraints assumption is superior to that with the relaxed constraints assumption in predicting the plastic deformation characteristics of steel sheets; (2) The Hosford yield criterion is an effective phenomenological model for predicting the plastic deformation characteristics of steel sheets.