摘要: The work accomplished under the first two contracts was concerned with the type of failure induced by overmatching fragment simulators, i.e., those having a diameter greater than the thickness of the armor, as this was considered ... 展开 The work accomplished under the first two contracts was concerned with the type of failure induced by overmatching fragment simulators, i.e., those having a diameter greater than the thickness of the armor, as this was considered the most severe condition to which the armor would be exposed. It was then desired to complete the picture by showing the abilities of armor materials to resist penetration by undermatching fragments, which may be more representative of average combat conditions, considering that most of the fragments produced by random-fragmentation types of munitions are of relatively small size. Consequently, the research conducted under the present contract has been primarily concerned with armor behavior under impact by undermatching fragment simulators. The scope of the work has included the study of corollary conditions usually associated with undermatching fragments, viz., small fragment size, higher critical velocities (ballistic limits), and high striking velocities. In addition to these conditions, some of the effects of variations in fragment hardness have been studied. It was found that the formula previously developed for predicting the performance of certain armor materials under impact by overmatching fragments does not hold for undermatching conditions, with the possible exception of nylon. 收起