基于细观层次的混凝土随机骨料建模

摘要

In mesoscopic sense,concrete is a three-phase composite material which is composed of aggregate,mor-tar and the interface layer between them.The interface layer is the weakest part of concrete,and is also the main cause of concrete’s low tensile strength.MATLAB software is used to establish three random aggregate models of circle,polygon and elliptic shape and to generate the interface layer of certain thickness.Furthermore,finite ele-ment software ABAQUS is employed to establish two-dimensional mesoscopic numerical model of concrete.Compu-tation examples show that the algorithm is simple and the model is reliable.By introducing interface layer and grid subdivision,we provide a foundation for the numerical simulation of concrete’s damage fracture mechanism,and effectively solve the problem of connection among MATLAB,AUTOCAD and finite element software.%在细观层次上，将混凝土视为由骨料、砂浆和二者之间的界面层构成的三相复合材料，而界面层是混凝土的最薄弱环节，也是混凝土抗拉强度低的主要原因。基于 MATLAB 软件生成圆形、多边形和椭圆形3种随机骨料模型，并生成一定厚度的骨料界面层，结合有限元软件 ABAQUS 划分界面层单元，建立二维混凝土细观数值模型。通过算例表明：骨料投放算法简单，模型真实可靠。通过引入界面层并对其进行网格剖分，对多边形骨料模型进行单轴拉伸试验，得到的应力－应变曲线基本符合宏观混凝土单轴拉伸试验结果，为后续研究混凝土的损伤断裂机理提供了数值模拟基础，并且有效地解决了 MATLAB，AUTOCAD 和有限元软件之间的接口问题。数字模拟生成的多边形骨料分布情况占有率与真实骨料最接近，可用作混凝土的损伤断裂机理分析。