Publication

Abstract : Closed-cell aluminum foams of density 0.3 to 0.46  g/cc (1  g/cc=1,000  kg/m3) were exposed to incident shock waves of 10–11 bar (1  bar=1.01325×105  N/m2) pressure in a shock tube to study the shock-induced stress on the end wall, which was measured using a fast-response polyvinylidene difluoride (PVDF) sensor. The experimental results revealed amplification of the end-wall stress by 2.5 to 4 times compared to pressure exerted on the front surface of the foams. Shock compression of foams is discussed based on the stress history output of the PVDF. The properties of the densified foam samples, the particle and plastic wave speeds in foams, based on theory, are presented. A numerical analysis of loading the foams with shocks was conducted using Abaqus software to complement the experimental results. The numerical prediction of the end-wall stress also suggests stress amplification by a factor of 2.6 to 3.4. The information can be useful to designers of shock attenuators and defense shields using aluminum foams.