Improvement of the contour method for measurement of near-surface residual stresses from laser peening

A study was conducted to develop a methodology to obtain near-surface residual stresses for laser-peened aluminium alloy samples using the contour method. After cutting trials to determine the optimal cut parameters, surface contours were obtained and a new data analysis method based on spline smoothing was applied. A new criterion for determining the optimal smoothing parameters is introduced. Near-surface residual stresses obtained from the contour method were compared with X-ray diffraction and incremental hole drilling results. It is concluded that with optimal cutting parameters and data analysis, reliable near-surface residual stresses can be obtained by the contour method