Study on Crashworthiness and Structural Optimization Design of Bionic Multi-cell Hexagonal Conical Energy-Absorbing Structures

This paper presents a novel bionic hexagonal conical tube with a stiffness gradient, inspired by the microstructure of horsetail stems. The structural energy dissipation mechanisms were analytically derived using the Simplified Super Folding Element (SSFE) theory. Following experimental validation, numerical simulations were employed to compare the crashworthiness of double-hexagonal tubes (DHT) across varying rib topologies, establishing the edge-connected configuration (E-DHT-2) as the superior base design. A parametric study was then conducted to assess the influence of taper angle, hierarchical ratio, and wall thickness on energy absorption. Furthermore, multi-objective optimization was executed by combining Latin Hypercube Sampling (LHS), a Kriging surrogate model, and the NSGA-II algorithm. The optimized E-DHT-2 achieved a 15.16% increase in specific energy absorption (SEA) and an 8.78% reduction in initial peak crushing force (IPCF). These findings provide an effective design and optimization paradigm for advancing lightweight and high-safety structural energy absorbers.