Theoretical analysis and performance prediction on modified surface layer caused by ultrasonic surface rolling

Abstract

Ultrasonic surface rolling process (USRP) is a prospective approach that can improve fatigue property of a workpiece by improving compressive residual stress and microhardness in the modified surface layer, as well as improving surface roughness. However, because USRP is a complicated machining process, many studies on surface properties focus on experiment test and simulation method. Thus, analytical models of the modified surface layer should be established to facilitate the design and utility of the USRP. In the present work, analytical models of residual stress, plastic strain of modified surface layer, and surface roughness are proposed on the basis of Hertz contact theory and elastic–plastic mechanics, and the effects of processing parameters on the modified surface layer are predicted using the developed models. Results of the analytical models are consistent with experiment results. Therefore, the models can be used to guide the design of the modified surface layer and identify optimal processing parameters in USRP.