Effect of Residual Stress in Surface Layer on Plastic Yield Inception

This study aimed to acquire a comprehensive explanation on how the residual stress in the surface layer affects the contact behavior of solids. Plastic yield inception of residual stressed surface layer/substrate system during contact is simulated using the finite element method with the software ANSYS Workbench. The critical loads and locations for yield inception were acquired for contact systems with different residual stress levels and different surface layer thicknesses. Results show that the residual stress in the surface layer has little influence on the stress field in the substrate during contact. The influence of the residual stress on the critical yield load is mainly due to variations in the stress field in surface layer. A moderate compressive residual stress is preferable for increasing the critical yield load. An optimal value of compressive residual stress of 60% of the yield strength of surface layer was found to increase the critical yield load. The surface layer thickness and residual stress determine the yield inception location and the critical load of the contact system jointly.