Theses and Dissertations Collection

Today, thin-walled (TW) structures are known for their use in several fields such as aerospace, automotive, rail, and maritime. With the growing concern for life-threatening terrorist attacks, these structures have been studied for their use in structural engineering as well, as part of protective structural systems. With the goal of achieving excellent crashworthiness performance with the minimum possible weight, systems comprised of lightweight materials with high strength-to-weight properties are subjects of study. The primary objective of this study is to investigate the effect of carbon fiber reinforced polymers (CFRP) and polyvinyl chloride (PVC) foam reinforcements on the crashworthiness of tall, thin-walled circular aluminum tubes, to be used as energy absorbers. This investigation was done by experimentally testing tubes with inner diameter of 60 mm, wall thickness of 1.6 mm, and 120 mm in length with different reinforcement configurations under quasi-static axial loads. The effect of epoxy on energy absorption capability was investigated to determine whether adhesives are to be used to bond the tube wall and the foam core or not. In addition, tubes with CFRP and PVC foam reinforcing configuration and varying lengths (40 mm, 80 mm, and 120 mm) were tested to determine the most efficient configuration with tubes of different length-to-diameter ratios (L/D).The study concluded that CFRP and PVC foam reinforcements increase the energy absorption of tall aluminum tubes by 37% and the peak force by 20% compared to the control, unreinforced, aluminum tubes. Also, these reinforcements were found to have complementary effects on energy absorption capabilities of aluminum tubes. Although epoxy adhesion between the foam core and tube wall was found to increase the peak load by 2%, it does not improve energy absorption while increasing the mass of the specimen by 9%. 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) with a proportional increase in energy absorption with an increased length. However, it was found that the smaller the specimen, the higher the peak load.