Residual Stresses Due to Shot Peening in Springs
Residual stresses are a little counterintuitive to the idea that a stress is defi ned as a load acting over an area. Residual stresses are stresses that remain after a force has been removed. They are contained within the component without any external force acting on it. Residual stresses form in three main ways: deformation of a material due to external force, a volumetric change in the material (usually due to a phase transformation) or thermal contraction. The key point with them is that they occur more in one region compared to another. It is the variation between two regions in close proximity that causes a residual stress.