Vibration analysis of delaminated composite beams using analytical and FEM models

In this study, the effects of delamination length and orientation angle on the natural frequency of symmetric composite beams are investigated, analytically and numerically. The analytical method is developed using the Timoshenko beam theory. The transverse shear effect and the rotary inertia terms are taken into account in the governing equations of vibration. Two dimensional finite element models of the delaminated beams are established using contact element at the ANSYS. The values of the natural frequency in laminated beams are obtained using the normal penalty stiffness that is chosen as the elasticity modulus for the contact element of the delamination region. When the analytical results are compared with numerical results and the results in literature, it is seen that the results are very close to each other. It is shown that natural frequencies decrease when delamination length in the beam increases and the natural frequencies change with the change of orientation angle.