ABSTRACT
Manufacturing processes, i.e. the action of load and thermal stresses, create residual stresses in engineering elements [1]. These stresses acting in conjunction with those produced by live loads can threaten the safety of an engineering structure by creating and propagating fatigue cracks. The difficulty in measuring them non-destructively, the unpredictability of their magnitude, sense and direction, their adverse ability to combine with stress corrosion and environmental and fatigue situations and the difficulty in removing them can render them extremely troublesome. Residual stresses should be evaluated under operating conditions to assess their effect on the intended service capability of the component. This problem has been investigated for many years in the search for an inexpensive and reliable method of determining these stresses.
