小麦茎秆力学性能与微观结构研究

Mechanical Properties and Micro-structure of Wheat Stems

测定了小麦成熟期茎秆的力学性能,研究了茎秆的应力-应变规律。试验观察了茎秆的微观组织结构,得到了茎秆扫描电镜下的解剖构造图像。分析了小麦茎秆承载能力与微观组织结构的相互关系,建立了茎秆横截面的力学模型。结果表明：小麦茎秆是一种典型的多相、筛状、不连续、不均匀和各向异性的复合材料,茎秆具有较高的强度和良好的弹性,其承载能力取决于机械组织的厚度、维管束的数量以及各组织及其细胞之间的连接形式和连接强度,小麦茎秆的抗拉强度为30.36~52.65 MPa,弹性模量为1.14~2.05 GPa。

The mechanical properties of wheat stems in mature were tested, and the curves on stress-strain of wheat stems were measured by the electronic testing machine CMT2502. The microstructure of wheat stems was observed, and the SEM images of transverse and longitudinal section of wheat stem were got by scanning electron microscopy. The relation between mechanical properties and mierostrueture of wheat stems was analyzed, and mechanical model of wheat stem was established. The results show that wheat stem is a typical porous, no-continuous, no-homogeneous and anisotropic composite material. Wheat stems have enough strength and good flexibility, and its carrying capacity depends on the thickness of thick-walled cells and the numbers of vascular bundles, as well as the connection form and strength of cells in stems. The strength and Young＇s modulus of wheat stems are 30.36-52.65 MPa and 1.14- 2.05 GPa respectively.