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

Abstract 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.