摘要
[目的]通过重组竹抗弯力学性能试验和理论分析,提出重组竹抗弯强度和抗弯弹性模量特征值取值建议,拟合相关关系,为重组竹在建筑结构中的应用提供参考。[方法]参考ASTM D143-14等规范,对40个重组竹试件进行抗弯力学性能试验,结合试件的荷载-跨中位移关系曲线以及各阶段的破坏模态,分析其受力性能;运用统计学理论,分别采用参数法、非参数法以及相关规范计算抗弯强度和抗弯弹性模量特征值。[结果]由试件的荷载-跨中位移关系曲线可知,重组竹抗弯破坏经历3个阶段,加载初期变形与荷载呈线性关系,此时试件处于弹性阶段;随着荷载增大,试件受拉区最外侧竹纤维的拉应力达到抗拉强度发生断裂,截面刚度降低,此时试件处于弹塑性阶段;继续加载,裂缝沿试件纵向和中性轴处发展,最终试件达到极限荷载后发生破坏,试件受压区未发现明显破坏。对于抗弯强度特征值,参数法计算结果均高于非参数法,基于正态分布和对数正态分布计算的抗弯强度特征值十分接近,且均大于Weibull分布计算的特征值;对于抗弯弹性模量,参数法、非参数法以及相关规范计算的特征值较为接近。[结论]对比3种计算方法的准确度,取非参数法计算的5%分位值作为抗弯强度特征值,取参数法计算的5%分位值作为抗弯弹性模量特征值,在此基础上,提出不同抗弯弹性模量等级对应的抗弯强度建议取值。
[Objective]Bending mechanical test and theoretical analysis of bamboo scrimber were carried out,as well as the suggestions on the characteristic values of bending strength and bending modulus of elasticity(MOE)of bamboo scrimber were put forward.The correlation was fitted to provide technical reference for engineering application.[Method]The bending mechanical properties of 40 bamboo scrimber specimens were tested as referred to ASTM D143-14 and other specifications,and their mechanical properties were analyzed in combination with the mid-span displacement curve and the failure modes of each stage.Using statistical theory,the characteristic values of bending strength and bending MOE were obtained by using parametric method,non-parametric method and relevant standard calculation methods respectively.[Result]According to the mid-span displacement curve of the specimens,the bending failure of bamboo scrimber occurs in three stages:at the initial stage,the deformation was linear with the load.With the increase of load,the stress of the outermost bamboo fiber in the tensile area reaches the maximum strength and fracture occurs,and the section stiffness decreases.At this time,the specimens are in the elastic-plastic stage.After continuous loading,the cracks developed along the longitudinal and neutral axis of the specimen,and finally the specimen failed after reaching the ultimate load,and no obvious damage was found in the compression area of the specimen.The characteristic values of bending strength calculated using the parametric method are all greater than those calculated using the non-parametric method,and the characteristic values of bending strength calculated using the normal and log-normal distributions are very close,and are all greater than those calculated using the Weibull distribution.For the bending MOE,the characteristic values calculated by the parametric,non-parametric method,and relevant standard are relatively close.[Conclusion]From the perspective of accuracy,take the 5%percentile value of non-par
作者
盛叶
何钰雯
郭任坤
何乘根
郭楠
Sheng Ye;He Yuwen;Guo Renkun;He Chenggen;Guo Nan(College of Transportation and Civil Engineering,Fujian Agriculture and Forestry University,Fuzhou 350002)
出处
《林业科学》
EI
CAS
CSCD
北大核心
2024年第7期149-157,共9页
Scientia Silvae Sinicae
基金
国家科技项目备案类(2023L3046)
福建省科技计划项目(星火项目)(2022S0029)
中建股份科技研发项目(CSCEC-2022-Q-58)。
关键词
重组竹
抗弯强度
抗弯弹性模量
特征值
bamboo scrimber
bending strength
bending modulus of elasticity(MOE)
characteristic value
