基于锥形压入总功的金属表面等轴残余应力检测方法

Residual stresses can significantly influence the mechanical performance of engineering structures. Therefore, the accurate evaluation of the equibiaxial residual stress in such structures is of great value. In the present work, the fractional change in the loading work was chosen as the analytical parameter. A linear relationship between the fractional change in the loading work and the normalized equibiaxial residual stress was determined via dimensional and finite element analyses. Based on numerous finite element simulations, new fitting equations were obtained for evaluating the equibiaxial residual stress by instrumented sharp indentation. Both numerical and experimental verifications were used to examine the accuracy and reliability of the newly proposed method. A biaxial stress-generating jig was designed to introduce equibiaxial residual stress into metallic specimens to mimic the residual stress. By comparing the residual stresses determined by the proposed method with the generated pre-stresses, the maximum relative error and absolute error were typically found within ±20% and 30 MPa, respectively.