Experimental and numerical study of measuring high welding residual stresses by using the blind-hole-drilling technique

Abstract

The hole-drilling strain gauge method, described in ASTM E837, is the common method used in evaluation of residual stresses. However, yielding of the material around the hole causes errors related to disregarding the hypotheses of the basic theory of the method. In this work, several welded specimens were prepared and welding residual stresses were measured by using the standard hole-drilling technique. Next, plasticity effects on the measured results of the hole-drilling technique were investigated by using numerical modelling and experiments. In the experimental part of this work, several tensile specimens with pre-existing holes were tested, and the errors at different load levels were evaluated. In the numerical part of the work, drilling a blind hole on a preloaded infinite plate was simulated, and the plasticity errors for different materials and loading combinations were studied. Based on the obtained results, a simple procedure is proposed to correct the measured stresses obtained from the hole-drilling technique for the cases when the measured stresses are uniform and exceed 50 per cent of the yield strength. These corrected results may be used as reference data in numerical studies of welds.