DYNAMIC AXIAL CRUSH OF AUTOMOTIVE RAILSIZEDCOMPOSITE TUBESPART 3:BRAIDED VS.WOVEN REINFORCEMENTS

摘要

This paper contrasts dynamic axial crush test results for weave and for braidreinforced automotive rail-sized composite tubes. Reinforcements were made principally ofcarbon fiber but also Kevlar? and E-glass and hybrid combinations of these three. Tubes weremanufactured using Resin Transfer Molding (RTM) with processing and molding techniques thatare suitable for the low cost high volume needs of the automotive industry. In total 134 dynamicaxial crush tests were conducted of 88.9x88.9 mm tubes with 2.54 mm thick walls. A 45°bevelon the lead end of each tube served as the crush initiator. Common to braids and weaves was thatconsistent and desirable dynamic axial crush response was demonstrated for almost all parameterconfigurations. Additionally, hybridization of carbon with Kevlar? was found to not be necessaryfor producing stable crush but did prove to be a useful tool for changing crush force levels andincreasing post crush integrity. While exceptions existed for particular weaves and braids, thosetubes reinforced with weaves had on the average superior energy absorption capabilitiescompared to those made with braids. This bias may in part be attributable to the much greater useof small fiber bundle aerospace grade fiber products for the weaves than for the braids.Additionally, while exceptions again existed, the ratios of peak to average values of crush force(Fp/Fav(D)) for braids were, on the average, higher and thus less desirable than those for weaves.