Ultrasonic wave scattering by microcracks in the fragmented polycrystals

Acoustic bulletin, Vol. 10 3, (2007) p.19-24
A scattering of longitudinal ultrasonic waves by pores and microcracks in the fragmented polycrystals, subjected to static and cyclic tests, is considered using the method of integral equations. The obtained dependence of the average full scattering cross-section for an individual disk-shaped microcrack versus its wave dimension is presented, that corresponds by its character to the similar dependence for the pores. The defect size is estimated, for which the scattering coefficients on the boundaries of grains, fragments and microcracks are the similar values. It is shown that the value, that corresponds to the start of microcracks merging under uniaxial extension, lies within the calculation interval.
a fragmented polycrystal, microcrack, acoustic scattering, non-destructive testing