Determination of stresses in aluminium alloy using optical detection of Rayleigh waves

In this paper, a non-destructive method for the determination of residual stress profiles as a function of depth in laminated aluminium alloy sheets is presented. An ultrasonic method using Rayleigh waves propagating along the sides of the sheet is proposed. The determination of residual stresses is based on the measurement of the relative variation of the ultrasonic wave velocity versus the depth. An experimental device, using the acousto-optic interaction, has been developed to measure the velocity of the Rayleigh wave. Several residual stress profiles obtained by this technique are shown. The latter are compared to other stress profiles obtained by other methods: layer removal method and acoustic detection using wedge transducer. (C) 1999 Elsevier Science B.V. All rights reserved.