Conventional uniform-thickness expansion-tube energy-absorbing structures suffer from excessively high initial peak crushing forces (IPCFs) and sub-optimal energy absorption efficiency. Inspired by the gradient stiffness characteristics of the inter node-to-node structure in Buddha’s Belly Bamboo, this study proposed an expansion-tube energy-absorbing structure design featuring a gradient stiffness. An LS-DYNA finite element simulation model was first established, validated through experimental results, and subsequently subjected to multi-objective optimization. The analysis results demonstrate that the stiffness-gradient expansion-type energy-absorbing structure designed in this study not only effectively reduces the IPCF during energy absorption but also further enhances its buffering and specific energy absorption (SEA).
Wang et al. (Sat,) studied this question.