Residual Stresses in Beams (With and Without Prior History) Numerically Assessed by the Crack Compliance Method

This work assesses the Crack Compliance Method (CCM) by the Finite Element Method (FEM). The CCM is a very powerful method that is based on Fracture Mechanics Theory. Its experimental application and set up is validated by this work. The numerical assessment of the CCM is performed on bending beams with and without prior straining history, to determine the best position and orientation of strain gauges, as well as the optimum number of readings. The prior straining history condition, in the analyzed components, is induced by an axial pulling before the beam is bent. Three levels of preloading are considered: low, medium and high (which are related to the yield strain of the simulated material); Isotropic and Kinematic hardening rules are also considered. Additionally, an experimental evaluation is also presented by introducing a new supporting system to cut a slot in the beams. The results obtained in this work, provide a quantitative demonstration of the effect of hardening strain on the distribution of the residual stress in beams. In the same manner, the theoretical formulation of the CCM has been evaluated validating the application of this method for the determination of residual stress fields in mechanical components.