Dynamic compressive loading of expanded perlite/aluminum syntactic foam

This paper addresses the analysis of expanded perlite/aluminum (EP/A356) syntactic foams under dynamic compressive loading conditions. Experimental and numerical analysis are conducted in order to determine compressive stress-strain response, effective material properties and deformation mechanisms. Foam samples are manufactured by combining A356 aluminum alloy with expanded perlite particles that introduce 60-65% porosity. Under compressive loading these pores gradually collapse resulting in an approximately constant macroscopic stress level of the syntactic foam. Testing at different compression velocities shows that the expanded perlite particles increase the compression resistance at higher strain rates. The effective material properties of the syntactic foam increase both with density and loading velocity. Infrared (IR) thermal imaging and finite element analysis allowed the independent identification of the dominant deformation mechanism: single struts that are parallel to the loading direction buckle and trigger the formation of multiple collapse bands that are approximately perpendicular to the loading direction.