Angiosperm leaf venation is based on two major patterns, typically dicotyledonous branching and monocotyledonous parallel veins. The influence of these patterns on deformation and fracture properties is poorly understood. In this paper, three species of dicotyledons with netted venation and three species of monocots with parallel venation were selected, and the effect of vein distribution of leaves on their mechanical properties and deformation behavior was investigated. Whole images of leaves were captured using a digital camera, and their vein traits were measured using the image processing software Digimizer. A self-developed mechanical testing apparatus with high precision and low load was used to measure the tensile properties of leaves. The deformation behavior of the leaf was captured using a digital microscope during the tensile test. Results showed that the vein architecture of monocots and dicots is different, which had a remarkable effect on their mechanical properties, deformation behavior, and crack propagation behavior. The greater the diameter and the more the number of veins parallel to the tensile direction, the higher the tensile force, tensile strength, and elastic modulus of the leaves. The netted venation leaves evinced the elastic-plastic fracture type, and the hierarchy venation provided resistance to fracture propagation of cracks in the leaves by lengthening the crack path. The leaves with parallel venation behaved in a predominantly brittle manner or elastic fracture type, and the parallel venation inhibited the initiation of cracks in the leaves by increasing the load at complete fracture of the leaves. The investigation provides reference for a stiffened plate/shell structure and bionic anticrack design.

中文翻译：

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数码显微镜下准原位拉伸试验对典型植物叶片变形行为和断裂机制的脉络分布影响。


被子植物叶脉基于两种主要模式，通常是双子叶分枝和单子叶平行脉。人们对这些模式对变形和断裂特性的影响知之甚少。本文选取了3种网状脉双子叶植物和3种平行脉单子叶植物，研究了叶片的脉分布对其力学性能和变形行为的影响。使用数码相机拍摄叶子的整体图像，并使用图像处理软件Digimizer测量叶子的叶脉特征。采用自主研发的高精度、低载荷力学测试仪测量叶片的拉伸性能。在拉伸测试过程中使用数码显微镜捕捉叶子的变形行为。结果表明，单子叶植物和双子叶植物的叶脉结构不同，对其力学性能、变形行为和裂纹扩展行为有显着影响。直径越大，与拉伸方向平行的叶脉数量越多，叶片的拉伸力、拉伸强度和弹性模量就越高。网状脉络叶片表现出弹塑性断裂类型，层次脉络通过延长裂纹路径来抵抗叶片中裂纹的断裂扩展。具有平行脉络的叶片主要表现为脆性方式或弹性断裂型，并且平行脉络通过增加叶片完全断裂时的载荷来抑制叶片中裂纹的萌生。研究结果为加劲板壳结构和仿生防裂设计提供参考。