VIBRATION OF SANDWICH BEAMS WITH DOUBLE DELAMINATIONS

The free vibration of sandwich beams with single and double delaminati ons has been solved analytically without resorting to numerical approx imations. Various assumptions for the vibration mode shapes and local deformation at the delamination fronts have been examined. Comparison with experiments then verifies the validity of these assumptions under given geometry and boundary conditions. The solution for double delam inations reveals a multitude of natural frequencies within a narrow ra nge, resulting from both higher modes and mixed modes of vibrations.