Measurement of Through-Thickness Residual Stress

Abstract

Measurement of residual stresses through thickness using the layer-removal or sectioning method is traditionally a very time-consuming process, which often makes obtaining a large number of data impractical. For localized residual stresses such as due to welding, the measurement may become more tedious and prone to error in both measurement and analysis. Fortunately, the slitting method, when combined with wire EDM, makes the experimental procedure straightforward, requiring only a single strain gage installed on the surface opposite the cut. A large amount of data can be recorded as the depth of cut is being extended incrementally with high precision wire EDM. The basic assumptions of the method are that the stress does not vary in the transverse direction, and the deformation due to cutting is linear elastic. In this chapter we will present the procedures to be used in measurement of the through- thickness residual stresses.