多面体骨料大体积混凝土三维细观模型生成  

Generation of 3-D mesoscale models for massive concrete with polyhedral aggregates

作　　者：武亮[1] 王菁[1] 何修伟[1] 糜凯华 

机构地区：[1]昆明理工大学电力工程学院,昆明650500

出　　处：《应用力学学报》2015年第4期657-663,709,共7页Chinese Journal of Applied Mechanics

基　　金：国家自然科学基金(51269007)

摘　　要：将混凝土视为由粗骨料、砂浆质以及两者之间的界面组成的三相复合材料,用细观方法研究混凝土特性,提出了新的随机算法并生成三维细观有限元模型。这种方法基于Mote Carlo随机样本原理,由一个给定的骨料级配随机生成多面体骨料颗粒,按照互不相交原则逐一投放到混凝土模型试件中。将判断骨料是否互不相交转化为判断一个线性规划问题是否有解,能有效地提高模型骨料含量率及模型生成速度。文中提出的所有算法在MATLAB中都易实现,与COMSOL软件相结合能更高效地完成有限元网格剖分。计算实例表明,对于骨料含量高的大体积三四级配混凝土,这种方法能满足数值建模的需要。The behavior of concretes is studied analytically using mesoscopic approach which treats the concrete as a three-phase composite materials consisting of coarse aggregate, mortar matrix with fine aggregate dissolved in it, and interfacial zones between the coarse aggregate and the mortar matrix. For such mesoscopic study, a new stochastic algorithm is developed for generating random aggregate structures for polyhedral aggregates of massive concrete in 3-D space, producing specimens with comparably high aggregate content and realistic distribution. This method is based on the Monte-Carlo random sampling principle wherein the aggregate particles are generated from a certain given grading curve and placed one by one into the concrete specimen in such a way that there is no overlapping with particles already placed. The problem of checking of aggregates overlapping each other is transformed to determine whether a simple linear programming has a solution or not. These algorithms are implemented readily in MATLAB, and the finite element mesh can be generated effectively by combining the commercial software COMSOL with MATLAB. Numerical examples show that the mesoscale models obtained can meet the requirements of numerical modeling for massive concrete, such as three-graded concrete and fully-graded concrete for dams.

关 键 词：混凝土 细观结构 混凝土骨料 有限元分析 网格划分 

分 类 号：TU528.36[建筑科学—建筑技术科学]