Compaction wave characteristics of polymeric foams under dynamic loading

Abstract

The continuum scale shock wave theory has been extensively used to characterize the compaction wave propagation in polymeric foams. However, experimental full-field measurements are scarce to validate such shock wave models. In this study, dynamic experiments with the help of ultra-high speed imaging in conjunction with digital image correlation (DIC) to characterize the compaction wave propagation in polymeric foams. A direct impact is applied on a polymer foam sample using a Hopkinson bar apparatus. The experiment is conducted by shooting a projectile directly at the specimen at an impact velocity of 90 m/s. Typical characteristics of the compaction wave such as compaction wave velocity, compaction wave profile, full-field particle velocities are obtained from the DIC measurements. Furthermore, using a non-parametric method, inertia stress and hence the full-field axial stress is calculated across the compaction wave.