Composite steel-CFRP SHS tubes under axial impact

Composite steel-carbon fibre reinforced polymer (CFRP) tubes combine the benefits of the stable, ductile plastic collapse mechanism of the steel and the high strength to weight ratio of the fibre/resin composite, to form a composite tube with high energy absorption capability. This paper presents experimental results of square hollow section (SHS) composite steel-CFRP tubes subjected to axial impact. A number of different steel SHS geometries and two different matrix layouts of the CFRP are investigated. The dynamic results are compared with quasi-static results of composite steel-CFRP SHS and dynamic results of steel SHS and CFRP SHS. It is shown that the crashworthiness properties of load uniformity and specific energy absorption of the composite steel-CFRP tubes exceed those of the steel-only and CFRP-only tubes. An additional advantage of the CFRP application technique is that the CFRP may be retro-fitted to existing steel tubes, and the energy absorption capacity is shown to be markedly improved by such application. A theoretical method to calculate the dynamic mean crushing load which includes the effects of strain-rate is shown to compare well with the experimental results. (C) 2008 Elsevier Ltd. All rights reserved.