Scattering of obliquely incident shear waves from a cylindrical cavity.

Prior work has proposed the use of ultrasonic angle-beam shear wave techniques to detect cracks of varying angular location around fastener sites by generating and detecting creeping waves. To better understand the nature of the scattering problem and quantify the role of creeping waves in fastener site inspections, a 3D analytical model was developed for the propagation and scattering of an obliquely incident plane shear wave from a cylindrical cavity with arbitrary shear wave polarization. The generation and decay of the spiral creeping waves was found to be dependent on both the angle of incidence and polarization of the plane shear wave.

Measurement of surface wave transmission coefficient across surface-breaking cracks and notches in concrete.

In this paper, a technique for measuring a surface wave transmission coefficient across surface-breaking cracks and notches in a heterogeneous but globally isotropic material (concrete) is presented. Once the transmission coefficient across a surface discontinuity is known, its depth may be estimated. There are many difficulties in measuring the transmission coefficient experimentally owing to effects of wave path dependence, unknown characteristics of the receiver and the wave source, and the variation of impact event or receiver coupling.