Vibration of a laminated composite plate with closing delamination

Vibration of a laminated composite plate with a single and closing delamination is analysed in the present paper by using the finite element method. The delamination of layers is modelled by using additional boundary conditions in the delamination front. Contact forces between delaminated layers are also considered in the model by applying a node-to-node contact model. The influence of the delamination length and position on changes in natural frequencies and modes of vibrations of the plate are investigated in the paper. In the present study the plate is excited to vibrate by a harmonic force or by a force impulse and the resulting time series are analysed using FFT. Results of numerical calculations are verified and compared against experimental data obtained for laminated composite plates with delaminations.