Study of Energy Contributions in Granular Materials During Impact

摘要

A drop-tower experimental setup was developed for the impact testing of 2D assembly of cylinders and 3D assembly of spheres with impactor velocity of around 6 m/s. This drop tower setup was used to load 2D granular assembly of polyurethane cylinders of 1"-1.25" length with three different diameters of 1/4", 3/8" and 1/2". A high speed camera was used for recording the images at speeds between 10,000 and 50,000 fps to monitor the deformation of the cylinders. The inter-particle forces in these experiments were calculated using a GEM based force inference technique. The resultant force networks in the granular assemblies were then qualitatively compared to the acceleration fields and strain fields observed during the experiments at different time instants. The conservation of energy was used to plot the evolution of energy components like kinetic energy, strain energy, friction and dissipative components during impact experiments.