基于ANSYS的混凝土微观层次开裂演化数值模拟

Numerical simulation of dehiscence of concrete based on meso-level by ANSYS

将由富勒曲线所确定的三维混凝土骨料级配曲线转化为二维骨料级配曲线,结合蒙特卡罗方法,确定了混凝土骨料颗粒数,编写了混凝土二维随机椭圆形骨料模型生成程序,在有限元软件ANSYS中模拟了混凝土的骨料、砂浆以及二者之间界面的二维三相组分。在所建立的模型的基础上对混凝土材料在外荷载作用下裂纹的扩展、贯通以及破坏的过程进行了开裂演化模拟。结果表明:骨料和砂浆间的界面层是混凝土的薄弱环节,界面层在数值模型中的模拟、界面单元参数的确定和破坏准则的选取是数值模拟能否成功的关键;在混凝土的破坏过程中先是混凝土界面单元破坏,然后裂纹沿着骨料的边缘进一步发展,并形成贯通,直至失稳破坏,与物理试验的结果保持了一致。

Translating the three dimensional grading curve of aggregate which determined by Fuller curve into two dimensional plane, combined with Monte-Carlo method to determine the amount of the aggregate and write the programme of generating the meso-level model of concrete, the model is based on 2D random ellipse structure and describes the concrete as a complex material which consists of aggregate, sand pulp and interface.Based on the model, a research on how the cracks expense and cut through in the concrete and result in the damage of the concrete is conducted.Seen from the result：the interface is the vulnerable area of the concrete, the determination of the parameter and the damage criterion of the interface element is the governing fact of whether the numerical simulation can be successful.During the evolution, the interface unit destroyed at first then the crack expense along the edge of the aggregates, cutting through the concrete and finally destabized and damaged.And this is consis- tent with the result of the experiment.