On the elastic behavior of syntactic foams

This work concerns composite materials called "syntactic foams", i.e., materials made by a polymeric matrix filled with hollow solid inclusions. Explicit formulae for the homogenized values of the elastic moduli of these materials are derived, by means of the physical model and the corresponding elastic solution used by Hervé and Pellegrini [Hervé, E., Pellegrini, O., 1995. Archives Mechanics. 47 (2), 223–246.]. The morphologically representative patterns theory of Bornert et al. [Bornert, M., Stolz, C., Zaoui, A., 1996. Journal of the Mechanics and Physics of Solids 44, 307–331.] is used to take into account both the influence of the filler gradation and the presence of "unwanted" voids in the matrix, factors that are shown to be important in characterizing the mechanical behavior of syntactic foams. Comparisons with both experimental and numerical results show that the techniques used are capable of predicting, with good accuracy, the elastic moduli of real syntactic foams, i.e., those arising from an actual production process.