A new spectral finite element for the study of face sheet-core disbond identification in a sandwich

A new two-node spectral finite element for a sandwich panel with 13DOF/node is formulated to study the face sheet-core disbond in a sandwich panel. The spectral element formulation results in an exact dynamic stiffness matrix for the element. The study on wave propagation characteristics for both healthy and disbonded sandwich panel is carried out. The numerical results obtained using this spectral element are validated by comparing with the results obtained through simulations using commercially available finite element software. The effect of core damping for waves propagating in both through-thickness and along the length of the panel is clearly demonstrated. The interaction of the waves propagating between the face sheet-core disbond is studied and using numerical examples it is shown that the amplitude change is a measure to identify the disbond whereas the arrival times can be used to estimate the size of the disbond.