Nonlinear biaxial tensile stress path experiment without intermediate elastic unloading for validation of material model

A linear stress path (LSP) experiment was performed using uniaxial and biaxial tensile tests with a cold-rolled mild steel sheet (SPCD; nominal thickness: 0.8 mm) as the test material. In the LSP experiment, the contours of plastic work and the directions of the plastic strain rates, beta, for a plastic strain range of 0.002 <= epsilon p0 <= 0.234 were measured. Then, the Yld2000-2d yield function was used to identify a material model that accurately re-produces the experimental data. Stepped nonlinear stress path (NLSP) experiments were also performed; the NLSPs consisted of several linear stress paths without intermediate elastic unloading. The measured work hardening behavior and beta values were compared with those calculated using the yield functions identified from the LSP experiment, namely the von Mises, Hill's quadratic, and Yld2000-2d yield functions. For the Yld200-2d yield function, both isotropic and differential hardening models were investigated. It was found that the data measured in the NLSP experiment are consistent with calculation results obtained using the Yld2000-2d yield function identified from the LSP experiment. Thus, it can be concluded that within the range of stress paths adopted in the NLSP experiment, the deformation behavior of a test sample can be accurately predicted using the material model identified from an LSP experiment.

Automated summary

This study conducted linear stress path (LSP) experiments and stepped nonlinear stress path (NLSP) experiments using a cold-rolled mild steel sheet. By comparing the experimental data and calculation results, it was found that the Yld2000-2d yield function identified from the LSP experiment accurately predicted the deformation behavior in the NLSP experiment.