Predicting the effect of compressive and tensile residual stresses in fracture mechanics specimens

This paper considers the prediction of the effects of tensile and compressive residual stress in fracture mechanics specimens by the application of a mechanical pre-load. This is considered in the context of a 'C' shape specimen which is mechanically pre-tensioned or pre-compressed to produce, respectively, a compressive or tensile residual stress in the region where the crack is introduced. Finite-element analysis is performed to simulate the pre-loading and the subsequent fracture loading of the cracked specimens. The finite-element predictions are compared with experimental data including residual stress measurements using neutron diffraction. A discussion is presented on modelling and material issues pertaining to the use of mechanical pre-loading as a means for introducing residual stress.