Influence of natural and initial acoustoelastic coefficients on residual stress evaluation: Theory and experiment

The velocities of the ultrasonic bulk waves propagating in a prestressed ma terial with orthorhombic symmetry are formulated in two frames of reference . From these velocities, acoustoelastic coefficients are theoretically dete rmined with the natural and initial coordinates. For each acoustoelastic co efficient, the differences between its expressions according to the two sys tems of coordinates are then theoretically calculated and experimentally de termined. From these results, the error on the residual stress evaluation d ue to the use of natural acoustoelastic coefficients rather than those defi ned with the initial coordinates is estimated. (C) 1999 American Institute of Physics. [S0021-8979(99)01017-8].