Indentation model to obtain residual stress based on deviator stress equivalence and its application

Residual stress on the surface of a structure component can be effectively small-invasive evaluated using the indentation method, which is important for evaluating the safety of a service structure. In this study, a novel indentation model based on the deviator stress equivalence was proposed to determine the residual stress in metallic materials that obey Hollomon's power law (H-law). The model described the relationship between equibiaxial or uniaxial residual stresses, H-law parameters, load, and displacement. Finite element analysis (FEA) was used to obtain the indentation load–displacement curves within various equibiaxial or uniaxial residual stresses for several H-law materials. The residual stresses predicted using the model were close to the reference residual stress given by FEA. For three types of the materials, the equibiaxial and uniaxial residual stresses with multilevel were applied to cross and single beams by bending loading, and conical indentation tests were performed. According to the experimental load–displacement curves, the residual stresses predicted by the model proposed were in good agreement with the applied residual stresses.