Crash Performance of Variable Stiffness Braided Fiberglass Composites

摘要

This paper evaluates the energy absorbing behavior of braided fiberglass composites made with novel fiber glass reinforcements to simulate their performance during low speed crash events. Fiber glass/epoxy tubes were braided with axial and bias reinforcements (30, 60, and 75 off-axis) and three fiber glass compositions: E-glass, a high-modulus fiber, and a high-elongation fiber. Five to seven specimens from fifteen sample types were destructively tested with an instrumented drop-weight impact tower at speeds of approximately 6400 mm/s. Subsequent analysis of force-time history showed that some architectures exhibited the desirable characteristic for this application wherein energy is absorbed very uniformly during crush. Tubes comprising the high-elongation fiber in the bias direction exhibit up to 29% increase in energy absorption rate coinpared to E-glass equivalents. High speed video and post-mortem photographs provided insight to the failure modes that were critical to making comparisons of material response.