A tensile properties identification model for steels in large strain

Abstract

Localized deformation in smooth round bar specimens during tensile testing often results in inaccuracies in the equivalent stress–strain curve beyond the onset of diffuse necking in metallic materials. Therefore, appropriate corrections are essential when addressing large strain problems. In this study, a novel three-function correction model is proposed to accurately determine the equivalent stress–strain response at large strains using axisymmetric notched tensile specimens through numerical analyses. The model incorporates the effects of material strain-hardening behavior, deformation evolution, and notch geometry, and its formulation consists of three functions with parameters that can be conveniently determined. Validation against numerical simulations and experimental data demonstrates that the proposed model provides excellent agreement, thereby confirming its feasibility and accuracy. Furthermore, because deformation in axisymmetric notched specimens is effectively localized within the notch region, the model shows strong potential for characterizing local tensile properties of heterogeneous structures (such as weldments) by strategically positioning the target material zone within the notched area.