Transient Response of a Composite Plate With Delamination

Abstract

Transient response of a composite plate with a near-surface delamination has been studied in this paper. A new technique developed by the authors to evaluate the Cauchy Principal Value integrals and the weakly singular integrals involved in the boundary integral equations has been employed and modifided to treat the corner points on the boundary. The time harmonic Green’s functions appearing in the boundary integral equation are evaluated by combining a stiffness method and the modal summation technique. To circumvent the difficulties associated with the evaluation of hypersingular integrals for cracks, the multidomain technique is employed. The accuracy and efficiency of the method are checked by comparing the displacements in a uniaxial graphite-epoxy plate containing a delamination with results obtained by a hybrid method. It is shown that the presence of the delamination significantly alters the surface response spectra of the plate. Results are presented in both time and frequency domains. The results show that the technique would be useful for ultrasonic nondestructive evaluation of defects in composite and anisotropic plates, and for studying dynamic response of such plates to impact.