用随机骨料模型数值模拟混凝土材料的断裂

Numerical simulation study of fracture of concrete materials using random aggregate model

将混凝土看作由水泥砂浆、骨料及二者间的粘结带构成的三相复合材料；根据混凝土骨料的级配随机产生了混凝土骨料结构，将有限元网格投影到该结构上，并根据单元的位置确定单元的材料特性，用以代表混凝土的三个相结构。提出了断裂韧性与强度综合破坏准则，采用非线性有限元技术模拟了单边裂逢受拉试件从损伤到断裂破坏的全过程，为混凝土破坏机理的研究和发展、混凝土计算强度提供了新的技术路径。

In this paper,concrete materials are taken as three-phase composites consisting of mortar matrix,aggregate and bond between matrix and aggregate. Aggregate structures are randomly generated according to the concrete mix. Mesh of finite element is projected on a generated aggregate structure of concrete and different material properties are assigned to the respective elements according to element location in three phases. A failure criterion combining fracture toughness and strength is proposed. Whole processes of single edge notch specimen are simulated from damage to fracture under tension-displacement control condition using nonlinear finite element method. A new research method is presented for investigating fracture mechanism and developing computing strength of concrete.