Evaluating the effectiveness of vibratory stress relief by a modified hole-drilling method

In this paper, a modified through hole-drilling method is developed to evaluate the effectiveness of the application of vibratory stress relief (VSR). The principal residual stresses at any specified point before and after the treatment of VSR are measured by this method with the same cemented commercially available three-element strain gauge rosette. By comparing the magnitude of the measured results, the effectiveness of the treatment of VSR can thus be determined. Thin butt-welded specimens are prepared to verify the accuracy of the modified hole-drilling method compared to that of the conventional hole-drilling method. The experimental results show that the percentages of the relative errors between these two methods are all within 2.9%. Therefore, this modified method shows good accuracy in the determination of residual stresses before and after VSR. Meanwhile, the maximum principal residual stresses at the measured points are effectively reduced by about 5.8% to 27% after the application of VSR, and the minimum principal residual stresses at the measured points are effectively reduced by about 9.6% to 31%.