Crashworthiness Analysis and Design of Metal/CFRP Hybrid Structures Under Lateral Loading

Recently, published research indicates that metal/composite hybrid structures, which combine the excellent specific strength and stiffness of composites with the competitive material cost and toughness of metals, have shown superior performance under axial and oblique loadings. Nevertheless, the crushing behaviors under lateral loading are still rarely reported. In this paper, lateral quasi-static planar crushing tests were carried out to investigate the mechanical response and crushing behaviors for aluminum/CFRP hybrid tubes with different configurational schemes (H-I and H-II) by comparing with their counterparts made of singular material (pure aluminum tube and pure CFRP tube). The experimental results indicated that pure aluminum tube showed a stable crushing process and possessed higher EA and SEA compared with CFRP tube. In addition, the EA of H-II hybrid tube was considerably much higher than that of the summation of their constituent components (increased by 110%). The SEA of H-II hybrid tube increased by 90% compared with aluminum tube. In order to further explore the energy-absorbing mechanisms of H-II hybrid tube, the numerical simulations were performed by adopting effective constitutive model and multilayer modeling technique. Based on the developed finite element model, a systematical parametric study was conducted to explore in detail the effects of aluminum wall thickness, the number of CFRP layers, as well as, fiber orientation on the crashworthiness of H-II hybrid tube, and the contribution of different energy-absorbing mechanisms to total energy absorption was quantified. It was found that varying aluminum wall thickness and the number of CFRP layers not only had a great influence on energy absorbed by different mechanism but also was capable to affect lateral stiffness, EA, and SEA of H-II hybrid tube. Finally, the H-II hybrid tube was further optimized by using a discrete optimization method to improve its crashworthiness characteristics, and the results showed that the SEA was improved by 67.9% from the initial design.