Finite Element Analysis of Residual Stress Induced by Single-Pass Ultrasonic Surface Rolling Process

Abstract

The formation mechanism of residual stress field (RSF) and the coupling mechanisms of RSFs after single-pass ultrasonic surface rolling process (USRP) are revealed. Based on simulation, the transient evolution and steady distribution of compressive RSF are analyzed, and the influences of process parameters (i.e., the movement distance of the ball in a single period L, ball radius R, static force F and ultrasonic amplitude A) on residual stress (RS) after single-pass USRP are investigated. The results show that the plastic strain, which is induced by the extrusion of the target surface with the ball applying static force and ultrasonic vibration, causes compressive RS layer mainly. A new RSF will be induced simultaneously when the ball vibrates for a period, then the RSF induced by each period couples with several adjacent RSFs, and a compressive RS layer forms on the target surface finally. Furthermore, the surface compressive RS, the depth of maximum compressive RS and the depth of compressive RS layer increase effectively with the increase in F. Decreasing R can increase the surface compressive RS while decrease the depth of compressive RS layer slightly. Increasing A can increase the depth of compressive RS layer obviously when F is small, while has less influence on compressive RSF when F is large. For a relatively small L, the surface RS is compressive and achieves a uniform distribution.