基于DIC方法的高温后混凝土应变局部化研究  

Research on strain localization of concrete after high temperature based on DIC method

作　　者：赵燕茹[1,2] 张杰 宋博[1,2] 王磊 时金娜[1,2] ZHAO Yanru;ZHANG Jie;SONG Bo;WANG Lei;SHI Jinna(College of Civil Engineering,Inner Mongolia University of Technology,Hohhot 010051,China;Key Laboratory of Civil Engineering Structure and Mechanics of Inner Mongolia,Inner Mongolia University of Technology,Hohhot 010051,China)

机构地区：[1]内蒙古工业大学土木工程学院,内蒙古呼和浩特010051 [2]内蒙古工业大学内蒙古自治区土木工程结构与力学重点实验室,内蒙古呼和浩特010051

出　　处：《混凝土》2022年第4期37-43,共7页Concrete

基　　金：国家自然科学基金资助项目(11762015,11362013)。

摘　　要：对高温后混凝土预制裂缝梁进行了三点弯曲试验,运用灰关联法对比分析了数字图像相关(DIC)方法与应变片和激光引伸计测量的应变与位移,两者灰关联度较高,说明DIC方法可用于高温后混凝土变形测量。同时通过DIC方法测得混凝土表面全场位移和应变,探讨了不同温度作用下、不同加载时刻混凝土位移不均匀性和应变局部化现象,结果表明位移在加载初期较均匀,随着荷载增大,位移不均匀现象开始显现;应变局部化现象逐步发展,在加载前期低速发展,在峰值荷载下显著发生;而高温会导致这两种现象加快发展,且更加显著。高温加剧应变局部化,峰值荷载时刻应变集中于裂缝尖端,致使破坏荷载降低。The three-point bending test was carried out on the precast cracked concrete beam after high temperature.The gray correlation analysis method was used to compare and analyze the strain and displacement measured by the digital image correlation(DIC)method and the strain gauge and laser extensometer,the gray value of both is high.It shows that the DIC method can be used for concrete deformation measurement after high temperature.At the same time,the full field displacement and strain of the concrete surface were measured by DIC method.The displacement non-uniformity and strain localization of concrete under different temperature and different loading moments were discussed.The results show that the displacement is uniform at the initial stage of loading and the phenomenon of uneven displacement begins to appear with the increases of the load.The localization of strain gradually develops,and develops at a low speed in the early stage of loading,which occurs significantly under peak load.And high temperature causes these two phenomena to accelerate and become more significant.The high temperature exacerbates the strain localization,causing the strain at the peak load to concentrate on the crack tip and reduce the damage load.

关 键 词：数字图像相关 混凝土 高温 应变局部化 位移不均匀性 

分 类 号：TU528.01[建筑科学—建筑技术科学]