Time-domain finite difference calculations for interaction of an ultrasonic wave with a surface-breaking crack (Q1081409)

Four two-dimensional configurations are considered in this paper. The first two concern a homogeneous slab (0\(\leq y\leq H\), \(-\infty x<\infty)\), with a surface-breaking crack \((x=0\), \(0\leq y\leq a)\), and without such a crack. The other two configurations concern semi-infinite slabs of different mechanical properties which are in welded contact over \(x=0\), \(0\leq y\leq H\). One of these has a surface-breaking crack in the interface \((x=0\), \(0\leq y\leq a)\), and the other has perfect contact over the whole interface. Results are presented for diffraction and corner reflection of an ultrasonic displacement pulse. Time-domain calculations have been carried out by the use of the finite difference method. The results are presented as full-field snapshots of the displacement fields at specified times, and as time histories of the particle velocity at the midpoint of the transducer-specimen interface at \(x=-H\), \(y=H\).