冬、夏采伐期毛竹主要物理力学性能的对比  

Properties of Bamboo in Different Cutting Periods

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作  者:方徐勤 王传贵[1] 张双燕[1] Fang Xuqin;Wang Chuangui;Zhang Shuangyan(Anhui Agricultural University,Hefei 230036,P.R.China)

机构地区:[1]安徽农业大学,合肥230036

出  处:《东北林业大学学报》2019年第2期70-73,共4页Journal of Northeast Forestry University

基  金:国家科技支撑计划项目(2015BAD04B0302)。

摘  要:以大别山区3年生毛竹为研究对象,分别在冬、夏两个采伐期采集试样,并进行物理力学性能的测试。结果表明:冬季采伐期的毛竹材气干密度(0.742±0.054)g/cm^3和基本密度(0.628±0.047)g/cm^3均大于夏季采伐期毛竹材的基本密度(0.645±0.043)g/cm^3和气干密度(0.755±0.040)g/cm^3,两个采伐期毛竹材密度差异均显著;在冬季采伐期采集的毛竹材弦向气干干缩率、全干干缩率、径向气干干缩率、全干干缩率及体积气干干缩率、全干干缩率分别是夏季采伐期的1.96、1.56、1.96、1.62、1.96及1.71倍,差异显著;顺纹抗压强度、顺纹抗剪强度、抗弯强度及抗弯弹性模量夏季采伐期采集的毛竹材均大于冬季采伐期的,差异显著。采用直线方程和曲线方程两种形式对所测力学属性与基本密度之间关系进行经验模型的预测,结果显示:抗弯强度适合用直线方程而顺纹抗压强度、顺纹抗剪强度及抗弯弹性模量用曲线方程拟合效果更佳,且显著相关;各力学强度均随着基本密度的增加而增加。两个采伐期力学性能的差异可能是两个采伐期的温度、降水等环境因子通过毛竹密度影响其力学性所致能。Taking 3-year Phyllostachys pubescens in Dabie Mountains as the object of study,the samples were collected in two harvesting periods in winter and summer,and conducted on mechanical strength and physical properties.The results were obtained by comparative study.The air-dry density(0.742±0.054)g/cm^3 and the basic density(0.628±0.047)g/cm^3 of P.pubescens in winter harvesting period are greater than that(basic density was(0.645±0.043)g/cm^3 in the summer harvesting period,the air dry density was(0.755±0.040)g/cm^3),and the density difference of the bamboo was significant in the two harvesting periods.In winter harvesting period,tangential air dry shrinkage rate,tangential dry shrinkage rate,radial air dry shrinkage,radial dry shrinkage,and volume air dry shrinkage,volume dry shrinkage are 1.96,1.56,1.96,1.62,1.96 and 1.71 times of those in the summer harvesting period,respectively,the difference is significant;the compressive strength parallel to grain,the shear strength parallel to grain,the bending strength and the bending modulus of elasticity of P.pubescens collected during the winter harvesting period were larger than those collected during the summer harvesting period,and the difference was significant.The empirical model is used to predict the relationship between the measured mechanical properties and the basic density by using the linear equation and the curve equation,and the bending strength is suitable for the straight line equation and for the compressive strength parallel to grain,the shear strength parallel to grain and the bending modulus of elasticity,the elastic modulus is better fitted with a curve equation.All the models are remarkable,and each mechanical strength increases with the increase of the basic density,and the difference of mechanical properties of the two harvesting periods may be that the temperature and precipitation factors of the two harvesting periods influence the mechanical properties of the bamboo by affecting the density of bamboo.

关 键 词:毛竹 采伐期 力学性能 物理性能 

分 类 号:S781.9[农业科学—木材科学与技术;农业科学—林学]

 

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