Elastic design of syntactic foamed sandwiches obtained by filling of three-dimensional sandwich-fabric panels

A non-conventional sandwich, made by a fabric panel core ®lled by a syntactic foam, and by resin-impregnated ®berglass skins, is studied in the elastic range, with the aim of giving guidelines to its minimum weight design. Standard homogenization techniques are employed to compute the elastic moduli of the skins, whereas a speci®cally developed homogenization method has been used to obtain the elastic moduli of the core. A simple but accurate relationship for computing the shear sti€ness of the sandwich was used in conjunction with the well-known formulae for the bending sti€ness. Comparisons with both experiments and numerical predictions show good accuracy of both the proposed homogenization methods and the overall sti€ness evaluation procedure