Dynamic Compressive Response and Failure Behavior of an Epoxy Syntactic Foam

Abstract

The high-strain-rate compressive behavior of an epoxy syntactic foam is examined in this study. A pulse-shaped split Hopkinson pressure bar (SHPB), modified for low-impedance material testing, was used to ensure that the samples deformed under dynamic equilibrium and at a nearly constant strain-rate. Dynamic stress equilibrium in the specimen was monitored for each experiment using piezoelectric force transducers mounted close to the specimen end-faces. Quasi-static experiments were also conducted to demonstrate rate effects of the foam, as well as to study its failure behavior. It was determined that the compressive strength of the foam increased with strain rate up to a transition strain rate of between 550 and 1030 s 1. For experiments conducted at strain rates above this transition range, strain-rate-induced damage caused the compressive strength of the foam to decrease. Based on the experimental results, a constitutive model with strain-rate and damage effects was developed, which described the test data well.