Axial crushing of triaxially braided composite tubes at quasi-static and dynamic rates

作者：McGregor Carla; Vaziri Reza^*; Poursartip Anoush; Xiao Xinran

来源：Composite Structures, 2016, 157: 197-206.

DOI：10.1016/j.compstruct.2016.08.035

• Braided composite tubes
• Axial impact
• Progressive crushing
• Energy absorption
• Rate effects

This paper presents the results of an experimental investigation into the behaviour of braided CFRP tubes subjected to quasi-static and dynamic axial crushing. Tubes of six different geometries, with round, rectangular or square cross-sections, with 2-4 plies of triaxial braids, were tested. Two types of square tubes were also tested with a plug initiator. Comparisons were made by examining the failure modes, load-displacement curves, specific energy absorption (SEA), and the ratio of the peak load to the average progressive crush load. When tested without a plug initiator, the crush characteristics of these tubes differed significantly under the two loading rates. Under quasi-static crush, tubes showed a greater tendency to fail in an unstable manner, characterized by global buckling, folding of the walls and crushing at both ends of the tube. Therefore, quasi-static crush testing should be used with caution when evaluating dynamic response of a structure. In dynamic testing, seven out of the eight configurations failed in a stable manner, with damage initiating at the bottom and propagating up the length of the tube in a splaying type failure mode. The smaller square and the round tubes performed the best, displaying higher SEA and lower load ratio values.