Experimental and Numerical Study on the Energy Absorption of Polyurethane Foam-Filled Metal/Composite Hybrid Structures

Hybrid structures have the advantage of combining different types of materials at the same time. The trend of lightweight design in the transportation industry has promoted the development and application of composite materials with good crashworthiness performance. Low-density crushable foam-filled metal-composite hybrid structures have potential advantages as energy-absorbing components. This study investigated the mechanical characteristics of four different polyurethane foam-filled hybrid structures and their individual components under quasi-static axial compression. The experimental results showed foam-filled hybrid structures could change the deformation mode and improve stability during the compression process. Meanwhile, these hybrid structures could also improve energy absorption compared with their individual components. Among the different configurations, specimen C-PU-C (i.e., polyurethane foam filler between an outer CFRP tube and an inner CFRP tube) had the highest energy absorption capacity, at 5.4 kJ, and specific energy absorption, at 37.3 kJ/kg. Finally, a finite element (FE) model was established to analyze the mechanical characteristics of the hybrid structures by validating the simulation results against the experimental results.