Dynamic behavior of one-dimensional foam disk chains during low-velocity impact

Abstract

This study experimentally analyses the deformation and energy retention behavior of ten closed-cell PVC foam disks constituting a one-dimensional granular chain subjected to low-velocity impacts. A pressure-driven impactor loads disk chains of two densities, each at 1 and 10 m/s. The deformations of the disks are captured using high-speed cameras, and the chain's input and output forces are recorded during the impact. Energy retained by the chain and the disks is calculated using the deformations of the disks, input, output, and contact forces. The results show that the energy retained by the chain of H130 foam is 3 times greater than that of the H35 foam at 1 m/s and is about twice as high at 10 m/s. Normalized with respect to input energy, the relative energy retained by the chains of H35 foam is more than that of the H130 foam for the same impact velocity and is higher at lower impact velocities for both foams. In addition, the energy the disk chain retains decays along the chain, and the decay rate is higher for lower impact speeds, implying that the disk chain should be longer for higher impact speeds to mitigate the energy fully.