Research on low-velocity impact damage mechanism and energy absorption characteristics of bionic-inspired sandwich structure of illicium verum

In response to the demand for lightweight, energy-absorbing, and low-damage impact-resistant structures in fields such as aerospace and other fields, this study integrates bionics with mechanical metamaterials to design and fabricate a GB/PA12 composite structure using Illicium verum as the bionic prototype. Through theoretical modeling and experimental research, the influence mechanisms of inclined beam angle and impact energy on the low-velocity impact performance of the structure are systematically revealed. The results show that the damage mode of such structures is dominated by brittle fracture. Among them, the structure with a 30° inclination angle exhibits the best load-bearing stability, while the structure with a 60° inclination angle exhibits superior energy absorption stability. Especially under the 9 J impact, the 60° inclination angle structure achieves the optimal comprehensive performance, with significantly improved energy absorption and SEA increased by 1. 44 times compared with the 30° inclination angle structure. By comparing the experimental data with the results of the semi-empirical theoretical model established in this study, the validity of the model is verified, and the prediction errors of the model for key parameters are mostly controlled within 15%.