Analysis of the specific properties of glass microballoon-epoxy syntactic foams under tensile and flexural loads

Syntactic foam samples of varying volume fractions were fabricated using glass microballoons (GMB) as the filler in an epoxy matrix. The tensile and flexural properties of the foams were obtained from experiments for microballoon volume fractions up to 0.5. Special attention was given to their specific (per unit density) properties which established the means to compare materials of different densities. Even though the actual properties of the foams show a decreasing trend due to the hollow nature of the fillers, the specific properties, especially the specific modulus, show an increase in the 0.3 to 0.5 microballoon volume fraction regime. The foams were also analyzed numerically by creating a suitable representative volume element (RVE) and analyzing it using a commercial software. The RVE was a multi-particle unit cell having microballoons in the same size distribution and volume fraction as the foam itself. The effective overall properties were obtained over it and compared with the experimental results.