Damage produced in laminated plastic plates by small ball collision with the velocity of 50-140 m/s

The sizes of crater and radial cracks produced by small ball collision in s pecimens prepared by lamination of thin plastic plates were investigated. T he sizes increased with increasing ball velocity. The crater depth increase d under static-bending stress. A light-mass ball produced a deeper crater t han a heavy-mass ball for the same kinetic energy. In the case of static pr ess of a ball on a plate, the circumferential strain around the contact sit e was changed from compression to tension and a long crack and a few very s mall cracks were ultimately produced, with increasing pressure. On the othe r hand, several radial cracks were produced by a collision. Specimen geomet ry influenced the crack length distribution. The influence of lamination on crack production was investigated for several combinations of laminations using various plate thicknesses. Crack length produced in a specimen suppor ted only at both ends was slightly longer than that in a specimen with comp lete support. (C) 2000 Elsevier Science Ltd. All rights reserved.