Scattering of body waves by an inclined surface-breaking crack

Parametrical studies are presented which display the variation of the scattered displacement field with angles of incidence and observation, angle of inclination and the frequency of the incident wave, for scattering of elastic body waves by a surface-breaking crack which is inclined under an arbitrary angle with the free surface of an elastic half-space. By using the elastodynamic representation integral for the scattered displacement field, a system of (traction) boundary integral equations for the crack-opening displacement has been obtained. These boundary integral equations are hyper singular, and their solution, therefore, requires a special numerical procedure which was recently developed by the authors. Numerical results for the scattered far field are displayed in several figures. Both back scattering and forward scattering have been investigated. The results suggest the optimal choices of angles of incidence and observation for a maximum response in an ultrasonic test to detect and characterize surface-breaking cracks.