Acoustic emission from macro-microcrack configurations

In an earlier paper the effect of the proximity of a macrocrack on the acoustic emission generated by microcrack nucleation was analyzed under the restriction that the microcrack was located in the plane of the macrocrack. In this paper the microcrack may be arbitrarily oriented with regard to the macrocrack. The elastodynamic crack-opening displacements of both cracks were computed as numerical solutions of a set of coupled singular integral equations by use of the boundary element method. The fields were computed using the elastodynamic representation integral and the fast Fourier transform. Parametric studies showed the effect of microcrack orientation and distance from the macrocrack on the acoustically emitted fields.