ULTRASONIC SCATTERING MODELS FOR DISTRIBUTION OF CRACKS

To evaluate the initiation and growth behaviour of a distribution of c racks, an acoustic scattering model for a planar distribution of crack s is developed based on generalized reciprocity theory and Kino's scat tering formalism. Subsequently, an acoustic scattering model for a lin ear distribution of surface cracks in the form of the local stress int ensity factors is derived by using the elastostatic energy balance of crack formation. The numerical evaluation of the reflection coefficien t of Rayleigh waves for a linear distribution of semi-elliptic surface cracks is subsequently performed. The results show that the reflectio n coefficient, varying with respect to the crack depth ratio for a lin ear distribution of cracks, can effectively be evaluated by using the model.