Residual Stress Measurement Correction on Shot Peened AA2024 by Finite Element Analysis

Author:  R. Lebon, D. Delbergue, H.Y. Miao, M. Lévesque and P. Bocher
Source:  Conf Proc 2014: ICSP-12 Goslar, Germany (pgs.305-310)
Doc ID:  2014094
Year of Publication:  2014
Abstract:  
X-Ray diffraction is the most widely used technique to measure the residual stresses produced by shot peening. In this process, electropolishing is needed to access the in-depth residual stress state. Consequently, the measures must be corrected to take into account the ensuing stress relaxation. Moore and Evans (M&E) [1] proposed an analytical method for correcting the residual stress measurements in simple geometry components by relying on several simplifying assumptions that are not easy to validate in real life. Finite element analysis (FEA) approaches have to be developed and applied on complex geometries. Savaria et al. [2] improved the work from the Lambda research laboratory [3] based on the calculation of a socalled FEA relaxation correction matrix which quantifies the layer removal relaxation. However, this method highly depends on the component and removed pockets geometries. This paper investigates the dependency of the assumed removed layer geometry on the ability for the FEA approach to properly estimate the initial residual stress gradient. Moreover, the relaxation correction matrices are validated through numerical analysis and are applied to an actual AA2024 part. The results show a non-negligible difference between the M&E method and the FEA approaches.