Volume fraction and microballoon size effects on the compressive properties of epoxy/ceramic microballoon syntactic foam

Epoxy / ceramic micro balloon syntactic foams are used in marine and automobile industries because of their high specific strength and capability of absorbing energy. In this paper، the neat epoxy and 9 series of syntactic foams with 3 kinds of ceramic micro balloon with different diameters and crush strength in different volume fractions (20%، 40% & 60%) were fabricated. Effect of varying these parameters on the mechanical properties of syntactic foams is investigated. Besides of all، the effect of different loading rate is investigated، too. All of the samples were tested in 10-1، 10-2 and 10-3 strain rates. The results indicate that with increasing the strain rate from quasi-static to moderate rates، the strength of foams became more. Also the results show that the syntactic foam with bigger micro balloon was weak in compression. In syntactic foams of low volume fraction the size effects is more. On the other hand، with increasing the volume fraction، the crush strength of micro balloon is become effective. Plateau stress and absorbed energy results show these facts obviously. With increasing the strain rate، the strength is increased considerably.