A numerical investigation into the crack effects on the natural frequencies of the plates

In the current study, the effect of such parameters as the length, position and angle of crack on free vibrations of a cracked plate was examined by finite element method. The assumed crack was internal and through and its growth was ignored. In the proposed finite element model, crack was considered as a discontinuity on the plate surface and the results were compared with the results of other studies for validation which proved its acceptable precision. The studies show that the thickness and mechanical properties of the plate do not influence the ratio of natural frequency of a cracked plate to natural frequency of an intact plate and that the other parameters change the stiffness and natural frequencies of a plate through affecting the modal shapes and stress intensity factors.