A novel model for obtaining both equi-biaxial and uniaxial residual stress of metallic materials by instrumented sharp indentation

Abstract

As a new method, the indentation technique has become popular for measuring residual stress and mechanical properties at surfaces due to its simplicity of use, in-situ applicability, and nano-to-macro range of measurements. In this study, a novel model for obtaining the surface residual stress of metallic materials is proposed by instrumented sharp indentation. The metallic material containing surface residual stress is equivalent to another non-stressed material with a different yield stress in Hollomon law from the perspective of indentation response. Thus, a unified equivalent material indentation (UEMI) model is established for measuring both equi-biaxial and uniaxial residual stresses within metallic structural materials. Additionally, only five parameters need to be calibrated via finite element analysis (FEA) in this model. Moreover, the novel model is successfully verified using lots of simulated materials from FEA and seven metallic materials experimental data found in the references. The results show that the predicted residual stress agrees well with the pre-applied residual stress which meeting the needs of engineering.