Low, Medium and High Strain Rate Characteristics of Cenosphere Aluminum Syntactic Foam for Blast and Impact Applications

Abstract

Syntactic foams are commonly used as a core of sandwich structures in the mitigation of blast and impact. With the advancement of foaming technology, new classes of aluminum syntactic foams are being developed and explored for their potential applications in blast and impact mitigation. In the present investigation, cenosphere filled aluminum syntactic foams developed using liquid metallurgy route are studied for their compression behavior under low (0.001 /s - 0.01 /s), medium (1 /s - 10 /s), and high strain rates (> 500 /s). Low and medium strain rate tests are conducted using servo-hydraulic machine whereas, split-Hopkinson pressure bar (SHPB) is used for high strain rate investigation. The foam exhibits peak stress at a strain of about 5%, and this stress is used to examine strain rate sensitivity and to determine sensitivity parameter at three different strain rate regimes considered in the present investigation. Based on this investigation, it is observed that there is considerable improvement in the compressive strength and energy absorption of foam at higher strain rates. Deformation phenomena are explained in terms of microstructural behavior under these strain rates.