LAUSR

Abstract In this study, the free vibration and impact response of composite plates with interfacial delamination are investigated based on the improved layerwise theory with finite element implementation. The interaction between the composite plate and the surrounding medium is simulated by the visco‐Pasternak foundation model. Hamilton's principle is used to derive the equations of motion for the delaminated composite plates. The impact responses of the delaminated composite plates are later solved by the Newmark algorithm for both clamped-free (C-F) and clamped-clamped (C-C) boundary conditions. Influence of the foundation parameters, damping parameter, longitudinal and interfacial delamination locations on eigenfrequencies and transient history are investigated and discussed. Numerical results illustrate that delamination reduces the natural frequencies and the middle plane delamination possesses the largest damage effect. With a stiffer foundation, the damped eigenfrequencies increase significantly and the transient responses also converge much faster. Moreover, the existence of delamination affects the higher frequencies dramatically which may further help identify delamination locations in composite plates resting on visco-Pasternak foundations for structural health monitoring.