Mechanically robust bamboo node and its hierarchically fibrous structural design

Si-Ming Chen; Si-Chao Zhang; Huai-Ling Gao; Quan Wang; LiChuan Zhou; Hao-Yu Zhao; Xin-Yu Li; Ming Gong; Xiao-Feng Pan; Chen Cui; Ze-Yu Wang; YongLiang Zhang; HengAn Wu; Shu-Hong Yu

doi:10.1093/nsr/nwac195

Mechanically robust bamboo node and its hierarchically fibrous structural design

Natl Sci Rev. 2022 Sep 22;10(2):nwac195. doi: 10.1093/nsr/nwac195. eCollection 2023 Feb.

Authors

Si-Ming Chen¹, Si-Chao Zhang¹, Huai-Ling Gao¹, Quan Wang², LiChuan Zhou², Hao-Yu Zhao¹, Xin-Yu Li¹, Ming Gong², Xiao-Feng Pan¹, Chen Cui¹, Ze-Yu Wang¹, YongLiang Zhang², HengAn Wu², Shu-Hong Yu^{1

3}

Affiliations

¹ Department of Chemistry, Institute of Biomimetic Materials & Chemistry, Anhui Engineering Laboratory of Biomimetic Materials, Division of Nanomaterials & Chemistry, Hefei National Research Center for Physical Sciences at the Microscale, Institute of Energy, Hefei Comprehensive National Science Center, University of Science and Technology of China, Hefei 230026, China.
² CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, Engineering and Materials Science Experiment Center, University of Science and Technology of China, Hefei 230027, China.
³ Institute of Innovative Materials (I2M), Department of Materials Science and Engineering, Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China.

Abstract

Although short bamboo nodes function in mechanical support and fluid exchange for bamboo survival, their structures are not fully understood compared to unidirectional fibrous internodes. Here, we identify the spatial heterostructure of the bamboo node via multiscale imaging strategies and investigate its mechanical properties by multimodal mechanical tests. We find three kinds of hierarchical fiber reinforcement schemes that originate from the bamboo node, including spatially tightened interlocking, triaxial interconnected scaffolding and isotropic intertwining. These reinforcement schemes, built on porous vascular bundles, microfibers and more-refined twist-aligned nanofibers, govern the structural stability of the bamboo via hierarchical toughening. In addition, the spatial liquid transport associated with these multiscale fibers within the bamboo node is experimentally verified, which gives perceptible evidence for life-indispensable multidirectional fluid exchange. The functional integration of mechanical reinforcement and liquid transport reflects the fact that the bamboo node has opted for elaborate structural optimization rather than ingredient richness. This study will advance our understanding of biological materials and provide insight into the design of fiber-reinforced structures and biomass utilization.

Keywords: bamboo node; biological materials; functional integration; hierarchical fiber; structural reinforcement.