混凝土软化本构关系与失稳断裂参数的计算  

Softening constitutive relationship and calculation of instability fracture parameters of concrete

作　　者：李霞 王利民[1] 徐世烺[2] 薛辉庭 LI Xia;WANG Li-min;XU Shi-lang;XUE Hui-ting(School of Science,Qingdao University of Technology,Qingdao 266033,China;School of Civil Engineering and Architecture,Zhejiang University,Hangzhou 310058,China)

机构地区：[1]青岛理工大学理学院,青岛266033 [2]浙江大学建筑工程学院,杭州310058

出　　处：《青岛理工大学学报》2019年第4期6-12,63,共8页Journal of Qingdao University of Technology

基　　金：国家自然科学基金资助项目(10272068;51378461);山东省自然科学基金资助项目(Y2006A29)

摘　　要：准脆性材料混凝土的断裂参数尺寸效应不仅与外观尺寸有关,也与材料细观结构相关.完全张开裂纹前方的韧带阻裂区域内的介质相互作用,以虚拟裂纹上的黏聚应力表示.该虚拟裂纹张开位移与黏聚应力之间的关系,也可称为材料的非弹性软化本构关系.断裂过程失稳应力强度因子KⅠ的估计,直接关系着断裂力学在该类材料中的应用.首先讨论断裂过程区各种软化本构关系模型计算方法,以及与相关实验数据的对比.然后,提出一种利用材料极限应力、黏聚裂纹段长度以及应力强度因子的关系,估计失稳强度因子的计算方法.对该估算方法与实验测试结果对照,大致与实验测试数据吻合.The size effect of the fracture parameter of quasi brittle material concrete is not only related to the external property of material,but also to structural dimension of this material.The medium interaction in the crack arresting zone of ligament in front of a fully open crack is expressed by the cohesion stress on the virtual crack.The relationship between the virtual crack opening displacement and the cohesive stress can also be referred to as inelastic softening constitutive relationship of the material.The estimation of instability stress intensity factor K I in fracture process is directly related to the application of fracture mechanics in engineering for this kind of materials.The calculation methods of various softening constitutive models in fracture process zone are discussed and compared with the relevant experimental data.Then,a method for estimating the instability stress intensity factor is proposed by using the relationship between the ultimate stress of materials,the length of cohesive crack part and the stress intensity factor.The estimation method and its numerical results are roughly in agreement with the experimental data.

关 键 词：混凝土 断裂过程区 裂纹黏聚应力 双KⅠ断裂模型 虚拟裂纹张开位移 

分 类 号：TU528.1[建筑科学—建筑技术科学] O346.1[理学—固体力学]