Experimental and Analytical Study on Homogeneous and Layered Al Matrix Syntactic Foams under Impact

Abstract Al matrix syntactic foams have been widely studied as impact protection materials. The impact behaviour of syntactic foams, especially for non-homogeneous structures, however, is not well understood. The impact response of Al matrix syntactic foams with both homogeneous and layered structures were studied experimentally and theoretically. Layered structures composed of large- and small-particle layers provided lower impact peak stress and higher ductility than the average values of the large- and small-particle layers. The energy absorption capacity of the layered structures is the sum of the energy absorption capacities of the constituent layers. An analytical model for stress and strain evolutions in Al matrix syntactic foams during impact was developed. The contact stress, inertia stress and base as a function of time was calculated as a function of impact velocity. The analytical model captures the key characteristics of stress fluctuation during impact. The predictions of the base stress agreed reasonably well with the experimental results, showing stress fluctuation with similar time interval and amplitude.