Abstract
Nowadays, thin-walled (T.W.) structures are known for their various applications in different fields such as aerospace, automotive, rail, maritime, and structural engineering. The primary objective of this study was to investigate the effect of CFRP and PVC foam reinforcements on the crashworthiness of aluminum T.W. circular tubes, to be used as energy absorber systems. This study was conducted experimentally by testing aluminum tubes with a diameter of 60 mm, a wall thickness of 1.6 mm, and a length of 120 mm with different wall reinforcement configurations (unreinforced, singly reinforced, hybrid, and with PVC foam-filled core with and without adhesive) under quasi-static loading. To determine the effectiveness of adhesive impregnation between the foam core and the tube wall, the effect of epoxy on the crashworthiness of specimens was examined. In addition, tubes with hybrid CFRP and PVC foam-filled cores reinforcing configurations with varying specimens length were tested to determine the most efficient configuration of different length-to-diameter ratios (L/D). It was found that CFRP reinforcement increased the peak load of aluminum tubes by 18% and reduced the oscillation of the load-displacement history in the post-crushing zone to a more plateau-like behavior. In addition, PVC foam shifted up the load-displacement history by 7 kN on average, increasing the energy absorption of the tubes by 19% compared to the unfilled tubes. The hybrid system (CFRP and PVC foam reinforcements) increased the energy absorption and the peak load by 37% and 20%, respectively, compared to the control unreinforced tubes. Therefore they showed complementary effects on the crashworthiness of these specimens. Epoxy impregnation between the foam and the tube wall did not provide improvement in energy absorption. Finally, the CFRP and PVC foam reinforcing configuration was found to be equally effective for tubes between 80 mm (L/D = 1.33) and 120 mm (L/D = 2.00) in length with a proportional increase in energy absorption with increased length.