Face sheet buckling of debonded sandwich panels using a two-dimensional elastic foundation approach

A two-dimensional elastic foundation model for analysis of the face sheet buckling behavior of sandwich panels with an embedded rectangular debond has been developed. The model is based on an energy method which assumes that the core behaves as an elastic foundation supporting the face sheets everywhere except over the debond. The face sheet buckling load is presented in a versatile form expressed into two buckling coefficients. Parametric studies are conducted to evaluate the influences of the foundation modulus, face sheet modulus, face sheet anisotropy, debond and panel dimensions, and aspect ratios. It is shown that the critical buckling load is very sensitive to the core modulus and flexural stiffness of the face and less sensitive to the debond size and face anisotropy. Model predictions are compared to experimental results obtained for sandwich panels consisting of glass/epoxy face sheets over a H100 PVC foam core with a range of square face/core debond sizes. Reasonable agreement with experimentally measured local buckling loads is observed for relatively small debonds. For large debonds the model tends to overpredict the buckling load.