An investigation on the stress–strain relationship of cold-rolled steel sheets used in the automotive industry

Abstract

Cold-rolled steels are used in every stage of the automotive industry, from engineering design to manufacturing, and advanced numerical studies of these steels require knowledge of their stress–strain behaviour. Existing stress–strain models for these steels either are only capable of accurate predictions over a limited strain range or are defined by many material parameters and the values of some of these parameters are not available in most of the existing design codes. This study presents an analytical approximation of the stress–strain relationship for cold-rolled steels. For this purpose, tensile tests were conducted with some commercial cold-rolled sheets used in the automotive industry. Data were analysed to construct a robust mathematical model. The residual sum of squares was employed as the common analysing parameter for both linear and non-linear models; residual diagnosis was also applied towards achieving robustness of the model.