Wave scattering of interior vertical crack in plates and the detection of the crack

The Scattering of waves by an interior vertical crack in a plate has been studied using the strip element method. A technique for the characterization of an interior vertical crack is presented. In this technique, two time-harmonic line loads are applied on the upper and lower surfaces of the plate symmetrically. Additional superimposed oscillations have been found on the curve of the absolute values of the displacement in the region between;he load and the crack. The superimposed oscillations depend on both the length and the depth of the crack. The crack length can be determined from the mean value of the peats of the additional oscillations on the upper and lower surface of the plate. The crack depth can be determined from the difference of the additional oscillations on the upper and lower surfaces. Approximate Polynomial formulae for predicting the length and the depth of a vertical crack in an isotropic homogeneous plate are proposed. Numerical examples ale given to demonstrate the present technique. (C) 1997 Published by Elsevier Science Ltd.