Structural design and analysis of impact energy absorption characteristics for pre-folded external double-layer biomimetic multi-cell thin-walled tubes

Multi-cellular tubes have gained wide application in vehicle engineering due to their exceptional energy absorption capabilities. Pre-folded thin-walled tubes offer advantages such as low initial peak force, stable deformation behavior, and high energy absorption efficiency. Therefore, this paper proposes a set of double-layer biomimetic multi-cellular tubes with pre-folded external walls. Solid specimens were manufactured using metal 3D printing and were combined with finite element models for analysis. An analysis of the impact energy absorption characteristics of pre-folded biomimetic multi-cellular thin-walled structures was conducted by varying parameters such as the number of folded outer wall edges, the number of fold patterns, the number of cellular elements, the thickness of thin-walled tubes, and the cellular element patterns. The results indicate that introducing double-layer multi-cellular tubes with eight edges and four fold segments effectively reduces the initial peak force of the thin-walled structure and enhances its energy absorption efficiency. The structure exhibits optimal crashworthiness when the number of cellular elements is four, and its overall crashworthiness is highest when the structure's thickness is 1 mm. This study provides a new idea to improve the energy absorption efficiency of thin-walled structures by replacing the outer structure in subsequent studies.