General stress-velocity expressions in acoustoelasticity

The velocity of a transverse wave propagating in an elastic body depends on the stress field of the body. If transverse waves are sent through a body with a uniaxial stress field, there will be proportionality between the principal-stress difference and the relative velocity difference between the waves polarized in accordance with the two main directions. This technique is used for determining uniaxial residual-stress fields. The main object of the investigation described in this paper has been to investigate the usefulness of the method in the case of biaxial residual-stress fields. Both theoretically and experimentally, the investigation has shown that there is also proportionality between principal-stress difference and relative-velocity difference for a biaxial field. However, the tests have also shown that inaccuracies with this method, on account for example of preferred orientation in steel materials, are of such an order of magnitude that the method cannot, at the present stage of development, compete with the more traditional methods, such as the drilling method and the X-ray diffraction method.