Analysis and optimization of foam-reinforced web core composite sandwich panels under in-plane compressive loads

This paper presents the analysis and optimization of sandwich plates simply supported on all four edges with a foam-reinforced web core subjected to in-plane compressive loads. Due to many failure modes of this kind of sandwich structure such as overall instability of the sandwich as a whole, face plate instability, face wrinkling and instability of the webs, the analysis of each mode is investigated and discussed in order to understand the physical behaviors of the whole structure and its components. Then, the sandwich plate subjected to a uniaxial compressive load is optimized for the minimum weight by taking into account the above four failure criteria. The "weakest link in the chain" concept is used, by which each of these assumed independent failure modes occurs at the same buckling stress in order to attain the minimum weight. Additionally, for any given set of materials, the optimum face thickness, web component thickness, web core component spacing, core depth, and foam core modulus for any values of in-plane compressive loads is evaluated analytically. A factor of merit is derived for the special cases of the same orthotropic and isotropic face and web materials. Thus, the best material can be selected, or a rational compromise can be made between weight savings and cost.