小径级圆竹顺纹抗压强度及其影响因素  

Compressive strength of small-diameter bamboo and its influencing factors

作　　者：代福宽 汪紫微 王汉坤 田根林 王传贵[3] DAI Fukuan;WANG Ziwei;WANG Hankun;TIAN Genlin;WANG Chuangui(Institute of New Bamboo and Rattan Based Biomaterials,International Center for Bamboo and Rattan,Beijing 100102,China;Key Laboratory of National Forestry and Grassland Administration/Beijing for Bamboo&Rattan Science and Technology,International Center for Bamboo and Rattan,Beijing 100102,China;School of Forestry&Landscape Architecture,Anhui Agricultural University,Hefei 230036,Anhui,China)

机构地区：[1]国际竹藤中心竹藤生物质新材料研究所,北京100102 [2]国际竹藤中心国家林业与草原局/北京市共建竹藤科学与技术重点实验室,北京100102 [3]安徽农业大学林学与园林学院,安徽合肥230036

出　　处：《浙江农林大学学报》2023年第6期1341-1347,共7页Journal of Zhejiang A&F University

基　　金：国际竹藤中心基本科研业务费项目(1632022016);国家自然科学基金资助项目(32071855)。

摘　　要：【目的】探究测试小径级圆竹顺纹抗压强度的方法,以及纤维鞘体积分数和维管束分布密度对顺纹抗压强度的影响。【方法】以苦竹Pleioblastus amarus、篌竹Phyllostachys nidularia、水竹Phyllostachys heteroclada和早园竹Phyllostachys propinqua等4种小径级竹材(胸高直径50 mm以下)为研究对象,采用圆竹形式的试件探究小径级竹材的顺纹抗压性能测试方法,测试不同长径比(试件长度与直径的比值)试件对顺纹抗压强度的影响。同时,利用基于YOLO深度学习算法开发竹材维管束检测模型对维管束数量和纤维鞘面积进行测定,以探索其对顺纹抗压强度的影响。【结果】不同长径比试件测试结果并无显著性差异,以数据稳定性为准,则2.0倍长径比试件测试结果较为合理。采用该长径比试件测试,早园竹顺纹抗压强度最大,为82.91 MPa,水竹顺纹抗压强度最小,为67.01 MPa。篌竹纤维鞘组织比量最大,为35.64%,水竹最小,为33.05%。苦竹的维管束分布密度最大,达7.94个·mm^(−2),早园竹最小,为5.77个·mm^(−2)。将不同种竹材作为整体对象的研究表明:纤维鞘体积分数正向影响顺纹抗压强度,而维管束分布密度对顺纹抗压强度的影响较小。【结论】小径级竹材顺纹抗压强度的测试宜采用2.0倍长径比试件,控制试件在(90±30)s内压溃。该试验选用的小径级竹材的顺纹抗压性能较为优异,纤维鞘体积分数(y)与顺纹抗压强度(x)之间存在y=260.44x-18.26线性相关性。[Objective]This study is aimed to investigate the testing method for determining the compressive strength of small-diameter bamboo culms as well as the impact of fiber sheath volume fraction and distribution density of vascular bundles on it.[Method]Four species of small-diameter bamboo,namely Pleioblastus amarus,Phyllostachys nidularia,Phyllostachys heteroclada,and Phyllostachys propinqua,with a diameter at breast height of less than 50 mm,were selected as research subjects before bamboo culm samples were utilized to investigate the compressive strength testing method for small-diameter bamboo and to examine the impact of varying length-to-diameter ratios on compressive strength.At the same time,a bamboo vascular bundle detection model based on the YOLO deep learning algorithm was employed to determine the number of vascular bundles and fiber sheath area so as to investigate their influence on compressive strength.[Result]There were no significant differences in the test results among specimens with different length-to-diameter ratios and the test results for the specimen with a length-to-diameter ratio of 2.0 were more reasonable.Of specimens at the length-to-diameter ratio of 2.0,Phyllostachys propinqua exhibited the highest compressive strength at 82.91 MPa while Phyllostachys heteroclada demonstrated the lowest strength at 67.01 MPa.The volume fraction of fiber sheath was highest in Phyllostachys nidularia at 35.64%and lowest in Phyllostachys heteroclada at 33.05%.The density of vascular bundles in Pleioblastus amarus was highest at 7.94 pieces·mm^(−2),while that of Phyllostachys propinqua was the lowest at 5.77 pieces·mm^(−2).Studies that treated various species of bamboo as a unified entity have shown that the positive effect of the volume fraction of fiber sheath on compressive strength was significant while the influence of vascular bundle distribution density on compressive strength was relatively minor.[Conclusion]A specimen with a length-to-diameter ratio of 2.0 is an ideal choice for testing th

关 键 词：小径级竹材 抗压强度 测试方法 纤维鞘体积分数 维管束分布密度 

分 类 号：S781[农业科学—木材科学与技术]