Bamboo-inspired hierarchical microlattice structures (BHMSs) for high strength and energy absorption
Creators: name: Song, Jian
name: Yan, Junfei
name: Yi, Bengang
name: Gong, Wenyuan
name: Du, Zhaojun
name: Liu, Tengyong
name: Liang, Darong
name: Xie, Changchun
name: Pu, Zihao
Publisher: name: Taylor & Francis
Year: 2023
Subjects: subject: Biophysics
subject: Space Science
subject: Physical Sciences not elsewhere classified
subject: Medicine
subject: Molecular Biology
subject: Sociology
subject: FOS: Sociology
subject: Biological Sciences not elsewhere classified
subject: Information Systems not elsewhere classified

description: Mechanical metamaterials as a category of lightweight materials have exhibited superior specific mechanical properties and energy absorption. However, lack of reasonable structural design always results in weakening or failure to achieve the optimal mechanical performance of metamaterials. Here, we firstly adopted bio-inspired and structural optimization methods to guideline the design of microlattice structures. Inspired by the strong and ductile ‘Moso’ bamboo, three bamboo-inspired hierarchical microlattice structures (BHMSs) were initially designed, and the bamboo’s features, viz., hollow, gradient distribution, and cellular, were imitated by designed BHMSs. Optimization design with the objective of maximum ratio of strain energy and reaction force was carried out to furthermore improve the mechanical properties of BHMSs. Afterwards, the optimal BHMSs were printed <i>via</i> Stereolithography. The compressive responses of BHMSs were elaborated by experiments and simulation. Results show that these designed biomimetic structures can be easily tailored <i>via</i> tuning the geometric sizes of unit cell, achieving high compressive specific modulus and strength 48.16 kPa m<sup>3</sup> kg<sup>−1</sup> and 1389.23 Pa m<sup>3</sup> kg<sup>−1</sup> and the energy-absorbing efficient 85.43% in the octet bamboo-inspired hierarchical microlattice structures (OCT BHMSs). The design strategies and findings shed light on the realization of advanced metamaterials with tailored mechanical properties. How to design ordered cellular structures for lightweight structures with high mechanical strength and energy absorption efficiency remains a crucial challenge in automation, aerospace and lightweight construction fields. Inspired by the lightweight and high load-bearing capacity of nature bamboos and metamaterials in the previous researches (Song et al., Materials &amp; Design, 2019, 173: 107773; Song et al., International Journal of Fatigue, 2017, 100: 126), here a comprehensive approach of bionics and optimization was proposed to design hierarchical microlattice structures with lightweight, good mechanical properties and high energy absorption efficiency. The bamboo’s characteristics, including hollow, gradient enhancement, and cellular, were completely copied to reasonably produce hierarchical microlattice configurations, while the optimal sizes were obtained though the optimization design. A combination strategy of bamboo-inspired and optimization design to realize light-weight and high mechanical metamaterials was provided.Mechanical properties of biomimetic structures can be tailored by tuning dimensions based on optimization.A high energy absorption efficiency in octet-truss bamboo-inspired hierarchical microlattice structures. A combination strategy of bamboo-inspired and optimization design to realize light-weight and high mechanical metamaterials was provided. Mechanical properties of biomimetic structures can be tailored by tuning dimensions based on optimization. A high energy absorption efficiency in octet-truss bamboo-inspired hierarchical microlattice structures.