基于XCT扫描图像的混凝土二维细观受压断裂模拟  

Two-dimensional meso-compression fracture simulation of concrete based on XCT images

作　　者：李俊生 任文渊[1] 张爱军[1] 李伟[1] 魏汉林 LI Junsheng;REN Wenyuan;ZHANG Aijun;LI Wei;WEI Hanlin(College of Water Resources and Architectural Engineering,Northwest A&F University,Yangling 712100,China)

机构地区：[1]西北农林科技大学水利与建筑工程学院,陕西杨凌712100

出　　处：《水资源与水工程学报》2021年第6期170-177,共8页Journal of Water Resources and Water Engineering

基　　金：国家自然科学基金项目(51978572);陕西省自然科学基础研究计划青年项目(2017JQ5052)。

摘　　要：为了研究混凝土细观层次断裂力学特性,对混凝土试件进行原位XCT扫描,基于扫描图像提出了具有真实内部结构特征的混凝土二维细观模型,并预先在水泥砂浆和骨料-水泥砂浆界面插入零厚度粘结裂缝单元用以模拟潜在的裂缝。通过对该模型进行混凝土单轴受压数值仿真模拟,讨论其裂缝的发展过程以及不同细观结构和相应参数对混凝土断裂损伤行为的影响。结果表明:数值模拟得到的混凝土二维模型抗压强度与试验测得的强度相接近;混凝土的抗压强度受到水泥砂浆和骨料-砂浆界面裂缝单元的绝对数值影响,其中水泥砂浆裂缝单元强度对材料强度起控制作用;骨料-砂浆界面裂缝单元强度与水泥砂浆裂缝单元强度的比率对裂缝衍生发展有显著影响。To explore the meso-scale mechanical properties of concrete,a two-dimensional finite element model were developed for concrete fracture modelling based on the images from in situ X-ray computed tomography(XCT)tests.Zero-thickness cohesive interface elements(CIEs)were embedded within cement mortar and aggregate-cement mortar interfaces in advance to simulate potential cracks.Meanwhile,numerical simulations of concrete under uniaxial compression were carried out to analyze the crack propagation and the influence of different meso-structures and corresponding parameters on the fracture damage behavior.The simulation results show that the simulated compressive strength of the two-dimensional model of concrete is close to the measured values by laboratory experiments.The compressive strength of concrete is mainly affected by the absolute value of mortar CIEs,in which the CIE strength of cement mortar plays a controlling role on the material strength,and the relative ratio between cement mortar CIE strength and aggregate-cement mortar CIE strength has a significant effect on the development of crack propagation.

关 键 词：混凝土 XCT扫描图像 细观模型 单轴压缩 数值模拟 零厚度粘结裂缝单元 

分 类 号：TV43[水利工程—水工结构工程] TU528[建筑科学—建筑技术科学]