On the Measurement of Residual-stress Gradients in Aluminum-alloy Specimens The modified hole-drilling technique is extended to the measurement of biaxial residual-stress gradients induced by edge-dimpling technique in 2024-T3 aluminum-alloy specimens

The assessment or prediction of fatigue life or strength improvement due to residual stresses requires knowledge of their magnitude and distribution. This paper presents an extension of the modified hole-drilling technique (MHDT) to the measurement of stress gradients in a biaxial­ residual-stress field. This is achieved by taking a series of 'point' measurements and evaluating the stress profile with due consideration to the effects of hole location, the interaction between holes and the redistribution of stress due to hole drilling. An application to the measurement of residual stresses induced in 2024-T3 aluminum-alloy specimens by edge-dimpling technique is described and the method of compensation for the effect of redistribution of stress is explained. The experi­ mental results are shown to be in good agreement with those obtained elsewhere by an analytic-numerical solution.