【作者】 赵吉坤；

【导师】 张子明；

【作者基本信息】 河海大学 ， 工程力学， 2005， 硕士

【摘要】 混凝土材料由于其自身诸多的优点，多年来一直在土木工程中被广泛应用。混凝土是一种由骨料和砂浆构成的非线性材料。由于混凝土浇铸初期的干燥过程和水化作用，使得骨料和砂浆结合面处存在大量的初始裂缝。很多研究表明：混凝土的非线性就是由于这些裂缝的张开、闭合和发展造成的。混凝土损伤过程涉及许多重要的细观力学机制，如裂缝的闭合、开裂、分叉及摩擦效应等。目前国际上已经开始注意到从混凝土细观尺度出发研究混凝土宏观损伤与断裂过程的许多优点，尤其是当今计算机技术的发展，为从细观层次研究宏观层次的力学问题开辟了广阔的前景。 本论文立足于对混凝土材料特性的认识，提出一个进行混凝土损伤与断裂过程模拟的细观数值模型。从细观角度，混凝土可视为砂浆、骨料和两者之间的粘结面组成的三相复合材料，将混凝土中的原始缺陷认为是初始损伤，通过统计理论中的Weibull分布来实现了这种随机损伤的随机性分布，建立了数学模型。形成了多种混凝土数值试件，并对混凝土数值试样拉压、单边裂纹数值试样拉伸以及三点弯曲梁数值试样进行了损伤与断裂模拟研究：并对三点弯曲梁的破坏全过程进行了尺寸效应分析。研究表明，本文提出的计算模型接近实际构件，对混凝土非线性描述具有相当高的精度。更多还原

【Abstract】 Because of its excellence, the material of concrete has being used for some years. The concrete being made up of bone and sand slurry is a kind of the nonlinear material. Due to the process of molding concrete initial stage’ dryness and hydratability, there are a lot of initial cracks in the bone and sand slurry’ combination. Many studies show that the nonlinear of concrete is caused by these cracks’ crazing and expanding. The process of concrete’ damage is involved in a great deal of the microcosmic mechanism, for example the close of cracks, crazing, fracture and so on. At present, the advantage of the microcosmic mechanics to study the process of concrete’ damage and fracture is being noticed. Especially, the development of computer, it inaugurates the vast foreground to study the macroscopical mechanical problem from the mesoscopic mechanics.This paper is based on the understand of the concrete material. The mathematic model to study the process of concrete’s damage and fracture is being put forward. At mesoscopic scale, concrete may be regarded as a three-phase composite consisting of coarse aggregate, mortar matrix and internal zones. Originality disfigurement of concrete being regarded initialized damage, the random distribution is based on the statistic Weibull’s distribution. The mathematic model is built by this way. Many kinds of concrete models come into being. This paper’s content is the numerical simulation of the draw and pressure to concrete, the draw to the one side crack concrete and three points bending girder’s damage and fracture, moreover, the analysis of the dimension law of the three points bending girder. The study show that the model is close to the real samples and the precision of concrete nonlinear.更多还原