抄録
Scattering cross-sections for the parallel penny shaped cracks are calculated b the boundary element method. The multiple scattering effect of cracks is generally large in thecase of the vertically arranged parallel cracks. However, it is shown that the multiple scattering effect becomes small in the low frequency range when the distance of cracks approaches to twice as large as the crack diameter. It is also shown that the local resonance phenomena are induced in the low frequency range. The mechanism of the resonance phenomena is revealed by the crack opening displacement and the radiation pattern of the scattered energy.
