Estimation of surface equi-biaxial residual stress by using instrumented sharp indentation

Herein, we describe a method that can be used to estimate the surface equi-biaxial residual stress of a material using instrumented sharp indentation. In this method, the fractional change in the loading curvature, rather than the contact area, was chosen as the analytical parameter; this fractional change can be more precisely obtained. A linear relationship between the fractional change in the loading curvature and the normalized equi-biaxial residual stress was found via dimensional and finite element analysis, and this linear relationship greatly simplifies the formulas associated with this method. Moreover, the proposed method was successfully verified using experimental data from our laboratory and from the literature.