Bio-inspired, helically oriented tubular structures with tunable deformability and energy absorption performance under compression. (October 2022)

• Record Type: Journal Article
• Authors: Tung, Cheng-Che; Chen, Yen-Shuo; Chen, Wen-Fei; Chen, Po-Yu
• Is Part Of: Materials & design. Volume 222(2022)
• Publication Date: 2022-10
• Subjects: Cellular solids -- Helically oriented tubular structure -- Auxetic metamaterial -- Energy absorption -- Bio-inspired material -- Finite-element simulation; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2022.111076
• Languages: English
• ISSNs: 0264-1275

Abstract

Graphical abstract: Highlights: Bio-inspired, helically oriented tubular structures with tunable deformability and energy absoption efficiency are designed and fabricated. Helically oriented tubular structures with low helix anlges exhibit auxetic behavior while those with higher helix angles show global buckling under compression. The helically oriented tubular structures possessed maximum energy absorption efficiency superior or comparable to conventional honeycomb structures. Mechanical properties and deformation mechanisms of helically oriented tubular structures are predicted and elucidated by finite element simulations. Abstract: This study designs a series of helically oriented tubular structures inspired by Bouligand-type natural materials to optimize their mechanical performance. Thermoplastic polyurethane-based helically oriented tubular specimens are fabricated by 3D printing and their mechanical properties and energy absorption efficiency under compression are investigated. An auxetic behavior with a negative Poison's ratio is observed for specimens with low helix angles (0°–12°), while specimens with higher helix angles (30°–90°) exhibit a typical buckling behavior and those with intermediate helix angles (13.85°, 16.36°) demonstrate a hybrid helical-like buckling mechanism. Finite-element simulations are performed to elucidate the deformation behaviors and stress distributions under compression. Experimental results show that the helically oriented tubular samples with 90° helix angles yield maximum energy efficiency and compressive strength of 440% and 124%, respectively, higher than for the helically oriented tubular samples with 0° angles. Cyclic tests further show that the 0° sample can almost recover to its original shape, while cracks and delamination are observed for the 30° sample after 200 cycles. The bio-inspired helically oriented tubular structures designed in this study can be applied in engineering, requiring lightweight and energy absorption performance.