Tuo Zhiwei, Shi Yu, Sun Xianyan, Cui Jiandong, Yang Kaisheng, Liang Yunhong, Liu Changyi, Lin Zhaohua, Han Zhiwu, Ren Luquan
The Key Laboratory of Bionic Engineering, Ministry of Education, Jilin University, Changchun 130025, China.
School of Mechanical and Aerospace Engineering, Jilin University, Changchun 130025, China.
Acta Biomater. 2024 Sep 15;186:342-353. doi: 10.1016/j.actbio.2024.07.039. Epub 2024 Aug 7.
Macrostructural control of stress distribution and microstructural influence on crack propagation is one of the strategies for obtaining high mechanical properties in stag beetle upper jaws. The maximum bending fracture force of the stag beetle upper jaw is approximately 154, 000 times the weight of the upper jaw. Here, we explore the macro and micro-structural characteristics of two stag beetle upper jaws and reveal the resulting differences in mechanical properties and enhancement mechanisms. At the macroscopic level, the elliptic and triangular cross-sections of the upper jaw of the two species of stag beetles have significant effects on the formation of cracks. The crack generated by the upper jaws with a triangular section grows slowly and deflects easily. At the microscopic level, the upper jaw of the two species is a chitin cross-layered structure, but the difference between the two adjacent fiber layers at 45° and 50° leads to different deflection paths of the cracks on the exoskeleton. The mechanical properties of the upper jaw of the two species of stag beetle were significantly different due to the interaction of macro-structure and micro-structure. In addition, a series of bionic samples with different cross-section geometries and different fiber cross angles were designed, and mechanical tests were carried out according to the macro-structure and micro-structure characteristics of the stag beetle upper jaw. The effects of cross-section geometry and fiber cross angle on the mechanical properties of bionic samples are compared and analyzed. This study provides new ideas for designing and optimizing highly loaded components in engineering. STATEMENT OF SIGNIFICANCE: The upper jaw of the stag beetle is composed of a complex arrangement of chitin and protein fibers, providing both rigidity and flexibility. This structure is designed to withstand various mechanical stresses, including impacts and bending forces, encountered during its burrowing activities and interactions with its environment. The study of the upper jaw of the stag beetle can provide an efficient structural design for engineering components that are subjected to high loads. Understanding the relationship between structure and mechanical properties in the stag beetle upper jaw holds significant implications for biomimetic design and engineering.
控制应力分布的宏观结构以及微观结构对裂纹扩展的影响是在锹甲上颚获得高机械性能的策略之一。锹甲上颚的最大弯曲断裂力约为上颚重量的154,000倍。在此，我们探究了两种锹甲上颚的宏观和微观结构特征，并揭示了由此产生的机械性能差异及增强机制。在宏观层面，两种锹甲上颚的椭圆形和三角形横截面对裂纹形成有显著影响。具有三角形截面的上颚产生的裂纹扩展缓慢且容易偏转。在微观层面，两种锹甲的上颚均为几丁质交叉层状结构，但两个相邻纤维层在45°和50°时的差异导致外骨骼上裂纹的偏转路径不同。由于宏观结构和微观结构的相互作用，两种锹甲上颚的机械性能存在显著差异。此外，设计了一系列具有不同横截面几何形状和不同纤维交叉角度的仿生样品，并根据锹甲上颚的宏观结构和微观结构特征进行了力学测试。比较并分析了横截面几何形状和纤维交叉角度对仿生样品机械性能的影响。本研究为工程中高负载部件的设计和优化提供了新思路。重要性声明：锹甲的上颚由几丁质和蛋白质纤维的复杂排列组成，兼具刚性和柔韧性。这种结构旨在承受其挖掘活动及与环境相互作用过程中遇到的各种机械应力，包括冲击和弯曲力。对锹甲上颚的研究可为承受高负载的工程部件提供高效的结构设计。了解锹甲上颚结构与机械性能之间的关系对仿生设计和工程具有重要意义。
