In previous papers (1, 2) we have analyzed the internal stresses in spherical particle composites for the cases where the particle is softer than the matrix (1), as in rubber particle filled polymers, or for the case where the particle is harder than the matrix as in ceramic filled glasses (2). Also, the analysis has been applied to porous composites such as foams in which case spherical voids simply replace the particles (2). A finite element analysis has been used for the calculation of internal stresses and for the prediction of elastic constants and strength of the composite with a suitable model geometry and proper boundary conditions. The results have been presented as a function of the volume fraction of particles or inter-particle spacing.