The State-of-Art Methods for Residual Stress Evaluation

Abstract

This chapter deals with description of the state–of-art methods for residual stress determination. As any stress quantity, residual stress has multi-component tensor nature. Also, unlike the live stresses, residual stresses cannot be determined by tracking their evolution from an initial state. Also, residual stresses are scale-dependent and hence if the gauge volume of the measurement is changed, the perceived stress state also gets changed. In this context, residual stresses are often classied into Type I (Macro-Scale Stress), Type II (Micro-Scale Stress) and Type III (Nano-scale stress). Various papers based on challenges of measuring residual stresses and measurement techniques were reviewed and described herewith. Description of various conventional as well as latest techniques for residual stress determination such as those based on (a) destructive and non-destructive methods and (b) qualitative and quantitative approach. Namely the methods such as X-ray diffraction method, Hole-drilling method, Neutron diffraction method, photo-stress coating method, curvature method, Magnetic and Eddy current techniques, and Eigen strain approach are described in the following sections.