Residual stress. Part 1 – Measurement techniques

TLDR

Residual stress is the stress that remains in a stationary body at equilibrium, and while it can be detrimental to material performance, it can also be deliberately introduced for benefit, yet it is difficult to predict compared to in‑service stresses. Thus, reliable measurement methods are essential to quantify residual stresses and assess the information they provide. This paper first reviews the impact of residual stresses on fatigue life and structural integrity, defines residual stresses, and evaluates measurement techniques by comparing their gauge volumes to the characteristic length scales of different stress types, with a second part addressing their origins in various materials.

Abstract

AbstractResidual stress is that which remains in a body that is stationary and at equilibrium with its surroundings. It can be very detrimental to the performance of a material or the life of a component. Alternatively, beneficial residual stresses can be introduced deliberately. Residual stresses are more difficult to predict than the in-service stresses on which they superimpose. For this reason, it is important to have reliable methods for the measurement of these stresses and to understand the level of information they can provide. In this paper, which is the first part of a two part overview, the effect of residual stresses on fatigue lifetimes and structural integrity are first summarised, followed by the definition and measurement of residual stresses. Different types of stress are characterised according to the characteristic length scale over which they self-equilibrate. By comparing this length to the gauge volume of each technique, the capability of a range of techniques is assessed. In the second part of the overview, the different nature and origins of residual stress for various classes of material are examined.