东北落叶松材单向顺纹受拉损伤模型  

Damage Evolution Model for Northeast Larch Wood under Parallel-to-grain Tension Load

作　　者：谢启芳[1] 张利朋 王龙[1] 钱春宇 

机构地区：[1]西安建筑科技大学土木工程学院,陕西西安710055 [2]机械工业勘察设计研究院有限公司,陕西西安710043

出　　处：《湖南大学学报（自然科学版）》2017年第11期109-116,共8页Journal of Hunan University:Natural Sciences

基　　金：国家自然科学基金资助项目(51278399);陕西省自然科学重大基础研究项目(2016ZDJC-23);国机集团科技发展基金资助项目(13科192号);西安建筑科技大学创新团体资助计划~~

摘　　要：从细观层次揭示木材顺纹受拉破坏的损伤演化机制,是建立木材损伤本构模型的基础.在分析木材宏观及细观构造特征的基础上,将木材等效为若干根并联的受拉木纤维,每根顺纹受拉木纤维等效为弹脆性的受拉微弹簧.基于概率思想,假定受拉微弹簧的极限应变Δ为服从某一分布形式fΔ(x)的随机变量,推导了木材顺纹受拉损伤演化方程.在正确设置木材声发射参数即峰值定义时间(PDT)、撞击定义时间(HDT)和撞击闭锁时间(HLT)的基础上,通过木材顺纹受拉试件破坏过程中的声发射试验确定了受拉木纤维极限应变分布函数的参数,进而建立了木材顺纹受拉损伤模型.分析结果表明,声发射累计振铃计数与木材顺纹受拉细观损伤的累积过程是一致的,可用于反映木材顺纹受拉过程中的损伤演化特征.It is very important to explore the damage evolution mechanism of wood under tensile loading at meso scale,which is the foundation of establishing the damage constitutive model. In this paper,the component characteristics of wood at both macro and meso scale were analyzed,based on the assumption that wood is equivalent to numerous tension fibers in parallel and every tension wood fiber is equivalent to an elastic brittle tensile micro spring. The damage evolution equation was derived based on the assumption that the ultimate strains of tensile micro springs are random variables that obey some form of distribution. Based on the correct setting of acoustic emission parameters PDT,HDT and HLT,the parameters of the ultimate strain distribution function were obtained by tensile acoustic emission tests on Northeast Larch wood specimens along the grain during the failure process. Furthermore,the damage evolution model was established.The analyzing results show a good coherence between the acoustic emission accumulative events and the damage evolution,and the acoustic emission tests are available for the damage assessment during the wood longitudinal tensile process.

关 键 词：木材 顺纹受拉 微弹簧 损伤模型 声发射试验 

分 类 号：TU366.2[建筑科学—结构工程]