独角仙鞘翅微结构及其纳米力学性能

Micro-structure and nano-mechanical property of the elytra(Coleoptera:Allomyrina dichotoma)

利用SEM对独角仙鞘翅的微结构进行了观测,并借助纳米压痕仪测试分析了鞘翅的纳米力学性能。SEM试验表明独角仙鞘翅是一种具有拱形空腔的中空轻质生物复合材料,其断面占空比为26.36%。鞘翅由外表皮和内表皮构成,而内表皮又通过11～12层纤维层采用45°角正交叠加铺设,层间辅以许多微纤维丝交叉连接方式编织在一起,形成层合板结构。试验测得鞘翅外表皮纳米力学性能分别为:硬度(0.28±0.13)GPa,弹性模量(5.62±1.21)GPa,接触刚度(1.67±0.14)×104 N/m。其纳米力学性能呈现拓扑分布规律,由头部至尾部区域有增大趋势。试验测试结果为后续研究中设计一种基于独角仙鞘翅的新型轻质仿生结构提供了仿生学模型和理论参考。

The micro structure of elytra was observed by SEM. The nano-mechanical property of elytra was tested and analyzed with a nano-indentation machine. SEM images indicate that the elytra of AlZomyrina dichotoma are lightweight biological composites with a hollow structure like as arch shape. The duty ratio of cross- section is 26.36 %. The elytra are composed of epicuticle（EPI） and exocuticle（EXO）. The exocuticle consists of 11~ 12 fiber layers, laying in quadrature manner with a ply angle 45~ plus lots of fibrils braiding across, which form a laminated plate structure. The hardness, modulus and contact stiffness of epicuticle in elytra acquired with nano-indentation testing are （0.28±0. 13） GPa, （5. 62 ±1. 21） GPa and （1. 67 ± 0. 14） X 104 N/m, respectively. The nano- mechanical properties of elytra present a topological distribution characteristic, namely is a gradually incremental tendency from the cephalosome zone to the empennage zone. The results may provide biological template and biomimetie theory to design a new lightweight bionic structure inspired by the elytra in beetle Allomyrina dichotoma for the further researches.