Effect of reinforcement layer number on energy absorption of aluminum-CFRP hybrid square tubes under axial loading: Experimental and numerical study

The effect of the number of carbon-fiber-reinforced plastic (CRFP) layers on the axial crushing capacity of aluminum–CFRP square hybrid tubes was investigated both experimentally and numerically. Increasing the number of CRFP layers led to more collapsed lobes and decreased collapsed lobe widths, resulting in an improvement of the energy absorption capacity. The simulation results revealed a distinct tube wall collapse mode in the 4-layer hybrid tubes. The higher bending stiffness of the composite layers in the 4-layer hybrid tube led to debonding of the interface between the aluminum and composite layers. After interface failure, the composite layers did not collapse following the aluminum tube wall and instead rebounded in the approximate longitudinal direction, which directly suffering the longitudinal crushing loading. This behavior led to the shortened plastic collapse width and improvement of the single-layer CFRP energy dissipation due to CFRP delamination.