Crashworthiness performance of quill-inspired bionic multi-cell tubes under axial crushing: theory, experiments, and optimization

Energy-absorbing structures require an effective balance between lightweight design, high energy absorption, and stable crushing response. This study proposes quill-inspired bionic multi-cell tubes (QBMTs) by integrating circumferential corrugations with internal bifurcated reinforcing ribs to enhance axial crashworthiness. Twelve configurations with corrugation amplitudes of 1/3, 1/5, and 1/10 and number of circumferential corrugations of 5, 8, 11, and 14 were investigated through quasi-static axial crushing tests, a simplified super folding element (SSFE)-based theoretical model, and high-fidelity finite element simulations. Compared with conventional single-wall structures, the QBMT exhibited more stable progressive folding, higher specific energy absorption (SEA), and improved crush force efficiency (CFE). Among the initial designs, the configuration defined by corrugation amplitudes of 1/5 and number of circumferential corrugations of 14 achieved the best overall crashworthiness. Multi-objective optimization integrating Gaussian process regression (GPR) and NSGA-II identified the optimal parameters as (t1 = 1.68) mm, (t2 = 0.57) mm, and number of circumferential corrugations of 8. The optimized QBMT increased SEA by 76.2% relative to the conventional single-wall structure while maintaining stable deformation, with experimental results agreeing well with numerical predictions. These findings demonstrate the effectiveness of coupling quill-inspired hierarchy, corrugated geometry, and multi-cell topology for lightweight crashworthy absorbers.