钻孔导致孔边木材残余变形和弹塑性损伤研究  

Residual strain and elastic-plastic damage of wood due to hole drilling

作　　者：唐践扬 宋晓滨[1,3] 郭宇 宋胤恺 TANG Jianyang;SONG Xiaobin;GUO Yu;SONG Yinkai(Department of Structural Engineering,Tongji University,Shanghai 200092,China;Key Laboratory of Performance Evolution and Control for Engineering Structures of Ministry of Education,Tongji University,Shanghai 200092,China;Shanghai Key Laboratory of Engineering Structure Safety,SRIBS,Shanghai 200032,China)

机构地区：[1]同济大学建筑工程系,上海200092 [2]同济大学工程结构性能演化与控制教育部重点实验室,上海200092 [3]上海市建筑科学研究院有限公司上海市工程结构安全重点实验室,上海200032

出　　处：《建筑结构学报》2023年第10期114-122,共9页Journal of Building Structures

基　　金：国家自然科学基金项目(51878477);上海市工程结构安全重点实验室开放课题(2020-KF08)。

摘　　要：为研究胶合木钻孔加工产生的孔周塑性变形导致木材力学性能下降的问题,开展了木材钻孔损伤测试,通过数字图像相关法(digital image correlation,DIC)测量了木材钻孔导致的孔周残余应变,并基于木材弹塑性损伤本构模型得到了钻孔损伤因子,分析了转速、孔径和木材种类等参数对孔周木材损伤的分布宽度和角度的影响。结果表明:木材孔周残余应变分布区域、残余压应变最大值和损伤相对分布宽度、分布角度等均受转速的影响较大,而受孔径大小及木材种类的影响较小;低转速时,顺纹残余应变主要分布在1#和3#象限内,横纹残余应变主要分布在2#和4#象限内,剪切应变均匀分布在孔周,而高转速时残余应变在木材孔周分布较均匀;孔周最大残余压应变随转速增加而增加,最大增加282%;所测试的三种树种中,云杉的最大损伤相对分布宽度最大,花旗松的最大损伤相对分布宽度最小,且云杉-松-铁杉和花旗松的最大损伤相对宽度随孔径增加而减小最多达75%。To investigate the plastic deformation of glued timber members caused by hole drilling,which may lead to a decline of mechanical properties,wood drilling damage tests were carried out.Digital image correlation(DIC)was used to measure the residual strain around the drilled holes.The drilling damage factor was defined and calculated based on the elastic-plastic damage constitutive model of wood,and the influence of drilling speed,hole diameter and wood species on the distribution(width and angle)of the damage was analyzed.The test results indicate that the distribution of the residual strain,the maximum residual compressive strain,the maximum relative damage distribution width and the maximum distribution angle are greatly affected by the drilling speed,but are less affected by the hole diameter and wood species.The residual parallel-to-grain compressive strain developed by the low drilling speed is mainly developed in the 1#and 3#quadrants around the holes;the residual perpendicular-to-grain compressive strain is mainly generated in the 2#and 4#quadrants around the holes;and the residual shear strain is generated in all four quadrants.The residual strain corresponding to the high drilling speed is relatively uniform.The residual compressive strain increases by up to 282%with the increase of drilling speed.Among the three wood species tested in this paper,the maximum relative damage distribution width of spruce is the largest,while that of Douglas fir is the smallest;the maximum relative damage distribution width of spruce-pine-fir and Douglas fir decreases by up to 75%with the increase of hole diameter.The research results can be used as a basis for elastic-plastic analysis of mechanical properties of bolted joints.

关 键 词：木材 钻孔损伤 数字图像相关法 残余应变 损伤因子 

分 类 号：TU366.2[建筑科学—结构工程] TU317.1