Numerical Study of Plasticity Effects in Uniform Residual Stresses Measurement by Ring-Core Technique

The Ring-Core method is a mechanical technique used to calculate the surface residual stresses in a material. In this paper, plasticity effects on the calculated results of the Ring-Core technique were studied by FEM analysis. For this purpose, the coefficients were obtained from an elastic finite element modeling. Then, the execution of the Ring-Core technique using bilinear elastic-plastic behavior for the material was simulated and finally the relaxed strains due to ring core milling were obtained. The plastic error due to yielding was calculated by comparing the applied stress and calculated stress from the FE simulation. Also, by using the prepared FE model, the effects of various parameters like state of loading, ring geometry and tangent modulus were investigated. Based on the obtained results, a suitable range for the ring diameter was proposed in order for achieves accurate results.