The diffraction of Lamb waves by a finite delamination situated on a random plane parallel
to the symmetric plane of a laminated plate is taken into account. Two imaginary planes are
introduced to solve the problem by adopting the method of mode matching. By taking an appropriate
finite number of terms of the infinite expansion series and some selected points on the two imaginary
planes through convergence and precision tests, a matrix equation is obtained to evaluate the
expansion coefficients numerically. Reflection coefficients versus the normalized length a/h and the
relative location h1/h of the delamination are calculated in the low-frequency domain, the relative
errors are found to be less than 1%. Results obtained indicate that the theory developed in this paper is
meaningful for the detection of both the size and the location of a delamination in a laminated plate by
cooperating with experimental techniques for the non-destructive evaluation (NDE) technology.
Subsonic Lamb waves in anisotropic plates
