Bio-inspired thin-walled energy absorber adapted from the xylem structure for enhanced vehicle safety

Throughout evolution, plants and animals have optimized their structure to thrive in a wide range of extreme environments, offering natural structures with both low mass and high-energy absorption capacities. Vascular plants have developed a specialized tissue known as the Xylem, which offers structural support and facilitates the transport of water, mineral nutrients, and signals throughout the plant. This study aims to enhance the crashworthiness of vehicles by adapting the Xylem structure to design an effective bio-inspired thin-walled structure. Several different crash tube configurations are considered first, and their crashworthiness performances are assessed based on two different metrics: specific energy absorption \((\text{SEA})\) and crush force efficiency \((\text{CFE})\), which are determined by using the finite element analysis software LS-DYNA. Then, the crash tube configuration with the best performance is chosen for further investigation. A surrogate-based optimization study is performed, and it is found that \(\text{SEA}\) and \(\text{CFE}\) are improved by 151% and 113% compared to an empty circular thin-walled crash tube. Furthermore, the simplified super folding element theory has been used for building a theoretical model that predicts the mean crushing force of the Xylem-mimicking structure. The simulation results and calculated values show a strong agreement, indicating that the proposed theoretical model is of high accuracy.