基于CT图像分析的准脆性材料轴压损伤研究  

Damage of quasi-birttle materials uniaxial compression based on CT image analysis

作　　者：朱红光[1,2] 易成[1,2] 单海霞[1,2] 张伟泽 

机构地区：[1]中国矿业大学煤炭资源与安全开采国家重点实验室 [2]岩石混凝土破坏力学北京市重点实验室,北京100083

出　　处：《中国矿业大学学报》2011年第5期816-822,共7页Journal of China University of Mining & Technology

基　　金：国家重点基础研究发展计划(973)项目(2010CB732002);煤炭资源与安全开采国家重点实验室项目(SKLCRSM09KFB08);中央高校基本科研业务费专项资金项目(2010YL06)

摘　　要：借助CT扫描获得了压缩破坏过程混凝土材料的内部密度分布特征,对CT图像进行分区讨论,通过分析微裂纹演化所引起的灰度变化,采用分形Rd指标来描述分区位置线上灰度变化及统计规律,并基于Rd指标定义了一个损伤变量.研究表明:1)所有位置线上灰度变化的Rd总值随荷载增大呈二次减小规律,这是微裂纹演化的不断局部化所致;2)不同的荷载阶段Rd值变化不同,荷载水平从零增大到0.6时,所有位置线上灰度变化的Rd值都下降较快,从0.6到0.9的过程,各位置线上Rd值上下波动;从0.9到主裂纹贯通,大部分位置线Rd值减小,靠近贯通区域的位置线上Rd值则略有增大;3)定义的损伤度与荷载成二次增大关系,这与实际相符较好.The distribution properties of density in concretes were investigated by means of CT scanning tests during compression.By dividing the CT image into six parts,the gray changes of position lines in each part caused by microcracks evolution is described using fractal Rd index,and its statistical law is got.Based on Rd decription of the gray changes,a damage variable is defined.It is shown that the average Rd value of all position lines in the CT image decreased with load as square relationship.The trend of Rd value of each line is different at different loads,when the load level increased from 0 to 0.6,Rd value of all lines decreased rapidly;from 0.6 to 0.9,Rd value of part lines fluctuates wildly and the other is almost the same;from 0.9 to failure,Rd value of lines closed to the region of crack perforation increased,other position decreased again.The damage variable defined by Rd index increased with load as square relationship,it coincide with real damage law and is capable for damage description.

关 键 词：损伤 微裂纹演化 CT Rd指标 

分 类 号：TU501[建筑科学—建筑技术科学]