含水率对重组竹静态和动态横纹冲击力学性能的影响  

Effect of moisture content on the static and dynamic impact properties of bamboo scrimber perpendicular to grain

作　　者：盛叶 张鸣轩 张峰 谢智锐 郭任坤 郭楠 SHENG Ye;ZHANG Mingxuan;ZHANG Feng;XIE Zhirui;GUO Renkun;GUO Nan(College of Transportation and Civil Engineering,Fujian Agriculture and Forestry University,Fuzhou 350108,China;CSCEC Strait Construction and Development Co.Ltd.,Fuzhou 350000,China;Fujian Tansheng Construction Engineering Co.Ltd.,Nanping 354200,China)

机构地区：[1]福建农林大学交通与土木工程学院,福州350108 [2]中建海峡建设发展有限公司,福州350000 [3]福建潭晟建筑工程有限公司,南平354200

出　　处：《林业工程学报》2024年第6期20-26,共7页Journal of Forestry Engineering

基　　金：福建省科技厅国家科技项目备案类(2023L3046);中建股份科技研发项目(CSCEC-2022-Z-58);福建省科技计划项目星火项目(2022S0029)。

摘　　要：重组竹是一种新型生物质复合材料。作为结构材应用于建筑物时,除了受静态荷载,不可避免地会受到冲击荷载的作用,如地震、爆炸、高速撞击、高空坠物等,结构本身的缺陷在动力作用下可能被放大。由于建筑物中的重组竹柱通常在顺纹方向承压,而在水平冲击荷载作用下,柱体主要承受横纹方向的冲击力。为了评估重组竹柱在不同湿度环境下对冲击荷载的适应性,以平均密度为1.13 g/cm^(3)的重组竹为研究对象,进行了不同含水率(4%,8%,10%,12%,16%)和冲击速度(10,13,16 m/s)下的静态和动态冲击试验。结果表明:重组竹横纹动态抗压强度随冲击速度(加载率)的增加而显著提高,从静态加载的2.39倍增加至5.63倍,而弹性模量变化不大。当含水率从4%增加至16%时,横纹动态抗压强度和弹性模量逐渐降低。通过拟合动力放大系数(DIF)和静动态弹性模量比值,得出了含水率和加载率对重组竹横纹冲击力学性能的影响公式,为重组竹冲击荷载下的本构模型建立提供了理论依据。Bamboo scrimber is a new type of biomass composite material that exhibits superior mechanical properties compared to wood like larch and can be easily processed into structural components such as beams and columns.While extensive research has been conducted on the static mechanical properties of bamboo scrimber,studies focusing on its behavior under dynamic loading conditions remain limited.In extreme environments,such as hailstorms,typhoons with debris,or impacts from external objects,materials may experience significant dynamic loads that can cause intense dynamic responses,potentially leading to cracking or failure of the bamboo scrimber,thus affecting the safety and longevity of the entire structure.Therefore,it is essential to analyze the dynamic response of the material to understand its mechanical performance under dynamic loads.Given that the compressive direction of bamboo scrimber columns in buildings is typically parallel to the grain,they mainly endure impacts perpendicular to the grain when subjected to horizontal impact loads.This study investigated bamboo scrimber with an average density of 1.13 g/cm~3,conducting static uniaxial compression tests at various moisture contents(4%,8%,10%,12% and 16%) as a baseline.Additionally,dynamic impact tests were performed on bamboo scrimber at the same moisture contents and different impact velocities(10,13 and 16 m/s),using a split Hopkinson pressure bar(SHPB) apparatus.The results indicated that the static compressive strength and elastic modulus of bamboo scrimber perpendicular to the grain decreased with increasing moisture content.Under dynamic loading conditions,the dynamic compressive strength of bamboo scrimber perpendicular to the grain significantly increased with the impact velocity(loading rate) while the moisture content remained constant.This increase ranged from 2.39 times of the static loading to 5.63 times,with the rate of increase gradually slowing.The impact velocity had a minimal effect on the elastic modulus.When the impact velocity remaine

关 键 词：重组竹 冲击性能 含水率 加载率 动力放大系数 

分 类 号：S781.9[农业科学—木材科学与技术]