Residual stress management: Recent advances in engineering methods for non-destructive measurement and beneficial redistribution of residual stresses

Abstract

Welding is used widely in the automotive industry for joining a variety of structural components and parts. Of paramount importance in these structures are their engineering properties, such as fatigue life, distortions, dimensional stability, and corrosion resistance, which can be affected considerably by the presence of residual stresses (RS). The knowledge of RS and the ability to control their distribution in welded structures is critical when evaluating their fatigue life and preventing catastrophic failures. An engineering concept of residual stress management (RSM) has been developed that addresses all aspects of residual stresses in structural elements. RSM includes three major stages in stress management, i.e. RS determination, RS analysis, and RS redistribution. Using this approach, stresses in structures and materials can be evaluated in each specific case either theoretically or experimentally, and the performance and fatigue behavior of such structures optimized. This paper is built as an overview of the RSM concept and its application in the fields of nondestructive measurement of residual and applied stresses and in treatment of structures with residual stresses to achieve better performance and longer fatigue life. All three stages of the RSM concept will be discussed, and for each of the stages, practical engineering approach examples will be given. An example of a project in which the residual stress distribution in a fillet welded joint was measured, analyzed, and changed by postweld treatment will be presented to demonstrate the effectiveness of the RSM approach. The advancements in the modern tools used in this project for nondestructive measurement of residual stresses using an ultrasonic computerized complex for residual stress measurement and the ultrasonic peening for redistribution of the residual stresses that allowed improving the quality of the welds and increasing their fatigue life will also be presented.