竹材薄壁组织拉伸性能及其变异规律的研究  

Tensile properties and its variation pattern of bamboo parenchyma

作　　者：王福利[1] 王献轲 周佳硕 谢浩 许费扬 邵卓平[1] Wang Fuli;Wang Xianke;Zhou Jiashuo;Xie Hao;Xu Feiyang;Shao Zhuoping(School of Forestry&Landscape Architecture,Anhui Agricultural University,Hefei 230036,Anhui,China)

机构地区：[1]安徽农业大学林学与园林学院,安徽合肥230036

出　　处：《北京林业大学学报》2020年第11期130-137,共8页Journal of Beijing Forestry University

基　　金：国家自然科学基金项目(11072001);安徽省自然基金项目(2008085QC131);安徽农业大学人才项目(yj2018-13,2017zd10)。

摘　　要：【目的】从力学角度看,竹材的薄壁组织扮演基体的角色,而因其几何形貌的限制,目前针对薄壁组织开展的力学方面的相关研究较少。探索薄壁组织的力学性能,尤其是基体材料属性的赋值,对竹材精细化仿真模型的建立起到关键作用,进而提高模拟分析结果的准确性。【方法】以毛竹材为研究对象,7组试样取自同一竹秆不同高度处节间,软化后切厚度为30和80μm的弦切片,其中厚度为30μm的切片用于测试薄壁细胞形态参数,厚度为80μm的切片用于制作有效试验段仅含薄壁组织的拉伸试样,并在力学试验机上结合光学引伸计完成竹材薄壁组织的拉伸试验,计算分析其抗拉强度、弹性模量和失效应变。【结果】竹材薄壁细胞长、宽、腔径和双壁厚在竹秆高度方向上无明显的变异规律;薄壁组织的平均抗拉强度为13.08 MPa,抗拉弹性模量为830.86 MPa,失效应变为1.98%,三者在竹秆高度上的变异规律均不明显;竹材薄壁组织拉伸性能与薄壁细胞形态之间的线性相关性较低。对薄壁组织拉伸失效断口的分析表明其拉伸失效的实质是胞间层分离与细胞壁断裂,本试验采用的毛竹材薄壁组织的平均抗拉强度在13.08~34.82 MPa之间。【结论】试验方法与结果均可靠,试验结果将为全面而深入地了解竹材力学性能及其数学模型的建立提供重要的参考价值,另外本试验方法将为植物材料力学性能的相关研究提供参考。然而,为提高测量结果的准确性还需进一步的深入研究,竹材薄壁细胞组织构造在竹秆高度方向上的变异规律与其力学性能之间的关系仍需探索。[Objective]Bamboo is a kind of typical unidirectional long fiber reinforced composite material.The reinforcement phase is bamboo fiber,and the matrix is parenchyma.At present,there are few researches on the mechanical properties of bamboo parenchyma limited by its geometrical morphology,while its mechanical parameters do play important role in building fine numerical model of bamboo,especially the assignment of matrix attribute.[Method]In this paper,7 groups of bamboo parenchyma from different heights of culm were extracted by slicing,the slices with a thickness of 30μm were used to geometrical morphology of parenchyma cells and the slice with a thickness of 80μm was used to perform tensile tests.The variations of its geometrical morphology and tensile properties including tensile strength,tensile elastic modulus and failure strain in the height direction of bamboo culm were tested and studied.[Result]The results showed that in the height direction of bamboo culm,geometrical morphology of bamboo parenchyma had no obvious variation pattern.The average tensile strength,tensile elastic modulus and failure strain of parenchyma were 13.08 MPa,830.86 MPa and 1.98%,and all the three tensile parameters had no obvious variation pattern in the height direction of bamboo culm.The linear regression analysis results showed that there were low correlationship among parenchyma tensile properties and parenchyma cell geometrical morphology.Tensile failure mechanism of parenchyma was analyzed,and it was found that the tensile failure of parenchyma was the tensile failure of parenchyma cell interface and cell wall,thus the tensile strength of bamboo parenchyma here ranged from 13.08 to 34.82 MPa actually.[Conclusion]The test method and results are all reliable,which could provide theoretical basis for the further study of mechanical properties of bamboo,especially for the numerical simulation of bamboo.However,deep study should be performed to improve the accuracy of test results,and the relationship between parenchyma mechanical

关 键 词：竹材 薄壁组织 细胞形态 拉伸性能 失效机制 

分 类 号：S781.9[农业科学—木材科学与技术]