Investigation into contributions of static and dynamic loads to compressive residual stress fields caused by ultrasonic surface rolling

Abstract

A compressive residual stress field caused by ultrasonic surface rolling process is produced due to association of both the static and dynamic loads. The present work is an analytical approach to finding contributions of static and dynamic loads to this field. This study considered various rolling parameters and material properties based on a rectangular Hertz contact area. In the ultrasonic-rolling simulation, a quasi-static model and a dynamic model were developed based on the effects of strain hardening and strain rate hardening, respectively. Moreover, in order to validate the proposed analytical approach, experimental verification was carried out on the Al6061-T6 aluminum alloy. By investigating rolling parameters such as rolling depth, radius of tool tip, linear velocity of tool tip, friction coefficient, amplitude and frequency, relationships between external loads and those parameters were established and contributions of static and dynamic loads to this field were also found out. Finally, an approach to effective enlargement of compressive residual stress field was obtained based on the finding results.