Generating Well Defined Residual Stresses in Laboratory Specimens

Abstract

Residual stresses play an important role in increasing and decreasing the possibility of failure. The magnitude and direction of the residual stresses is an important factor in the integrity of engineering structures, including those containing defects. Ideally, we would like to gain insight into the integrity of a structure through testing laboratory samples. The purpose of this paper is to review methods of introducing residual stresses into laboratory specimens that are either subsequently loaded to fracture or used to assess the influence of residual stress on material damage mechanisms. Three methods, mechanical, thermal and welding, are scrutinized and illustrative examples provided. The advantages and disadvantages are explored. We conclude that new methods that do not introduce microstructural changes during the generation of residual stress should be sought if an improved understanding of the effects residual stress on fracture is required.