竖向孔洞对木柱受压承载性能的影响研究  

Effect of Vertical Holes on Compressive Bearing Capacity of Timber Columns

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作  者:钟慧娴 陈勇平[1] 钟永[1] ZHONG Huixian;CHEN Yongping;ZHONG Yong(Research Institute of Wood Industry,Chinese Academy of Forestry,Beijing 100091,China)

机构地区:[1]中国林业科学研究院木材工业研究所,北京100091

出  处:《木材科学与技术》2024年第6期39-46,68,共9页Chinese Journal of Wood Science and Technology

基  金:中央级公益性科研院所基本科研业务费专项资金项目“木质材料功能化处理与评价”(CAFYBB2023PA004);“刺入式探测对木柱承载能力的影响机制”(CAFYBB2019SY033)。

摘  要:带孔洞木柱受压承载性能是古建筑木结构的研究重点之一。以古建筑常用树种落叶松(Larix sp.)木材为试验材料,采用人工开孔方法来模拟木柱内部孔洞缺陷,基于数字散斑图像(digital speckle image correlation,DIC)和力学试验机联用技术,研究竖向孔洞对木柱受压承载性能的影响,结合宏观和微观力学性能来揭示带竖向孔洞缺陷木柱的受压破坏机制。结果表明:在本试验条件下,竖向孔洞横截面面积对木柱极限荷载的影响大于孔洞长度的影响;带竖向孔洞木柱受压破坏模式主要表现为褶皱破坏,随着位移的增加,出现木材横纹撕裂和斜角度剪切破坏;木材纤维褶皱破坏和斜角度剪切破坏主要是木材管胞细胞壁屈曲导致,而木材横纹撕裂破坏主要沿木材管胞顺纹方向延展且断面呈不规则锯齿状;应变场分布图显示表明木柱孔洞端部位置的竖向应力、横纹应力和剪切应力均存在显著应力集中,验证了数字散斑方法预测古建筑木构件损伤位置的有效性。通过竖向孔洞对木柱受压承载性能的影响研究,可为古建筑木结构保护修缮提供参考依据。The compressive bearing capacity of timber columns with holes is a key research focus in ancient timber structures.In this study,larch wood(Larix sp.),commonly used in ancient buildings,was selected as the experimental material.To investigate the effect of vertical holes on the compressive bearing capacity of timber columns,an artificial opening method was used to simulate internal hole defects.The compressive test was conducted using digital speckle image correlation(DIC)in conjunction with a mechanical testing machine.The compressive failure mechanism in timber columns with vertical holes was examined through the macroscopic and microscopic mechanical properties.The results indicated that,under the conditions of this experiment,the effect of the hole’s cross-sectional area on the ultimate load of timber column was greater than that of the hole’s longitude direction.Fold failure was the primary compressive failure mode for timber columns with vertical holes,followed by the transverse tearing and oblique shear failure of the wood as displacement increased.Fold failure and oblique shear failure were primarily caused by the buckling of the wood tracheid cell walls,while transverse tearing failure primarily extended longitudinally along the wood tracheid cells resulting in an irregularly serrated cross-section.Additionally,the strain field distribution indicated that stress concentrations in the vertical,transverse stress,and shear stress occurred at the ends of holes,which demonstrated the effectiveness of the DIC method in predicting the damage location in ancient building wood components.This study provides a solid foundation for the protection and repair of ancient timber structures.

关 键 词:带孔洞木柱 受压承载性能 数字散斑图像(DIC) 竖向孔洞 极限荷载 破坏模式 应变场 

分 类 号:S781[农业科学—木材科学与技术] TU366.2[农业科学—林学]

 

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