Rate and architecture effects on progressive crush of braided tubes

The effects of biaxial braider yarn types, presence of additional axial yarn, and crushing rate on energy absorption of braided composite tubes was investigated. The braided preforms consisted of both biaxial and triaxial architectures using E-glass, carbon, and aramid fibers by themselves and as hybrids. Levels of mean crush load and specific energy absorption (SEA) were seen to increase with a tenfold increase in crush rate, with triaxial architectures showing the best overall performance. Mechanisms of crush were seen to change slightly with change in rate of crush, and there are indications that these are significantly affected by rate, although overall effects may not be affected as much. The use of tailored hybridization such as through the use of kevlar and glass biaxials and carbon axials in a triaxial architecture is shown to result in combined failure mechanisms that act synergistically, resulting in stable progressive crush at high values of SEA. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.