Braided-textile reinforced thin-walled conical tubular structures: Designing, manufacturing and testing

Carbon fiber reinforced composite (CFRC) tubes and polyurethane foams have been widely applied as lightweight energy absorbing elements. The purpose of this paper is to design and make braided-textile reinforced conical tubular structures and investigate the tapering effects on the textile structure and energy absorption (EA) characteristics. Single-layer CFRC conical tubes, double-layer CFRC conical tubes and foam-filled CFRC conical tubes were manufactured and their axial compression behaviors were tested and compared. The crushing modes and EA evaluation indexes were revealed and discussed. Compared with straight circular tubes, conical tubes have more progressive folding and much better crushing force efficiency (CFE). Compared with single-layer conical tube, the crushing mode of double-layer conical tube changes from diamond folding to concertina folding and the EA is increased by 4.5 to 6.9 times. The specific energy absorption (SEA) of tube D40/50 reaches 25.983 J/g, increased by 142.2% compared with that of the single-layer conical tube. Foam filling is beneficial to the total EA and improves the CFE to 100%, but multi-layer will reduce the foam filling effect.