Researchers at the University of Sheffield Advanced Manufacturing Research Centre with Boeing have matured their capability for measuring residual stresses in high-value manufactured aerospace components.

Residual stresses can be produced and affected by a range of manufacturing processes, including heat treatment, machining, and surface treatments such as shot peening. The fatigue life of a component has a direct correlation to the residual stresses that it inherits during the entire manufacturing process, therefore understanding the evolution and interaction of residual stresses during the whole manufacturing chain is of utmost importance.

At the AMRC, measurement of the residual stresses helps our engineers to understand the overall surface integrity and the service life of components when newer, faster and more advanced manufacturing techniques are being developed. Key conventional techniques for measuring residual stresses include hole-drilling - a destructive technique that involves the use of strain gauges for measuring changes in surface strains due to relaxation of residual stresses as the hole is drilled to a range of depths. Recently, the AMRC's Residual Stress Measurement Group (RSMG) has matured its capability to use X-Ray Diffraction (XRD), a non-destructive to semi-destructive technique to measure residual stresses within the component.

XRD can provide more accurate results than hole-drilling, with better resolution for surface and near surface measurements up to a depth of around 100 - 200