Energy absorption mechanics and design optimization of CFRP/aluminium hybrid structures for transverse loading

This study aimed to explore bending collapse behavior and energy absorption capacity of net aluminum (Al), net carbon fiber reinforced plastic (CFRP) and Al/CFRP hybrid tubes, respectively. Based upon the experimental tests, the transverse energy absorption of the Al/CFRP hybrid tubes was found to be even higher than the sum of corresponding net Al tube and net CFRP tube. Specifically, the CF-AL tube (the CFRP tube being placed outside the Al tube) increased the peak force by 6.7% and energy absorption by 20.6%. The AL-CF tube (the CFRP tube being placed inside the Al tube) improved the peak force by 14.1% and energy absorption by 19.1%. The experimental study indicated that overall, the CF-AL tube was of better crashworthiness characteristics. Subsequently, finite element (FE) analyses were carried out by correlating with the experimental results. Based upon this validated FE models, a parametric study and design optimization on the CF-AL tube (with respect to length, thickness and ply angle) were further performed. It was found that the optimization increased specific energy absorption (SEA) by 42.96% and mean crushing force by 37.75%; meanwhile the mass of optimum design decreased by 5.02%, exhibiting significant enhancement of crashworthiness characteristics.