Some Applications of Plasticity Theory to the Statics of Syntactic Foam

Abstract

A failure condition recently proposed for the composite material syntactic foam is applied to the inhomogeneous state of stress which occurs in a layered sphere exposed to external pressure. The sphere is composed of syntactic foam which surrounds an assumed perfectly elastic hollow inclusion of higher strength than the syntactic foam. In addition to the establishment of the stress level at which the syntactic foam begins to crush, an analysis similar to that of perfect plasticity theory is carried out to find the ultimate collapse pressure of the syntactic foam. The results are found to compare favorably with experimental data. This problem is of importance in the further development of buoyancy materials for deep submergence vehicles.