A Theoretical Model for the Ultrasonic Detection of Surface-breaking Cracks with the Scanning Laser Source Technique

In work reported at last year’s QNDE meeting, a first step towards the development of a model for the Scanning Laser Source (SLS) technique was presented, which provides an analytical formulation for the transient response of an isotropic, homogeneous, linearly elastic half-space submitted to a pulsed laser line source operating in the thermoelastic regime. The formulation takes into account optical penetration into the material and thermal diffusion from the source, and is therefore a suitable representation not only for the far field, but also for the field near the laser source, where these effects become significant. In the present paper, we report the progress made in the numerical analysis by the Boundary Element Method of the interactions of the previously obtained laser generated field with surface-breaking cracks. Some preliminary simulations of SLS experimental observations are presented.