Static response and free vibration analysis of the composite sandwich structures with multi-layer cores

• The LW/SE is extended to the composite sandwich structures with multi-layer cores.
• Two kinds of local models are presented to reduce the computational cost.
• The LW/SE is very suitable to the problems focused on the local responses.

The Layerwise/Solid-Element (LW/SE) method, which was developed based on the layerwise theory and the eight-noded solid element for the laminated composite stiffened plates and sandwich plates in the previous works [1], [2] and [3], is extended to the static response and free vibration analysis of the composite sandwich structures with multi-layer cores. In the LW/SE method, the layerwise theory is used to model the behavior of the laminated composite facesheets while the eight-noded solid element is employed to discretize the cores. The total governing equations of the composite sandwich plates are assembled by using the compatibility conditions to ensure the compatibility of displacements and the equilibrium conditions to ensure the equilibrium of internal force at the interface between facesheets and cores. In the numerical examples, the static analysis and free vibration analysis of the composite sandwich plates are investigated for the sandwich plates with double-layer honeycombs and pyramidal lattice cores. The proposed method is validated by using the 3D elastic models developed in MSC.Patran/Nastran code. Two kinds of local models of the sandwich plates with double-layer honeycombs are presented for the local response problems to reduce the computational cost in the case of guarantee analysis accuracy of the local response.