抄録
The dynamic response of a two-dimensional ordered particle packing composed of nylon-66 spheres of 1/4 inch diameter subjected to the impact of a spherical projectile was investigated experimentally as well as numerically by the discrete element method (DEM). First, the effects of the layer number of the particle packing on wave propagation and post-impact movement were examined. As the layer number increased, the contact forces that reached the base plate and the rebound velocity of projectiles decreased. Next, the effects of dissimilar material layers were examined. One or two layers of the particle packing were replaced with dissimilar materials, that is, alumina ceramic (Al2O3) spheres or steel spheres. The dissimilar material layers increased the scattering of the nylon spheres above the dissimilar material layers. The experimental results obtained using force sensors at the base plate showed that the dissimilar material layers reduced the contact forces at the base plate. As the mass of dissimilar material spheres increased, the magnitude of the contact forces at the base plate decreased and the rebound velocity of projectiles increased.
