基于背景网格的混凝土细观力学预处理方法

A pre-processing scheme based on background grid approach for meso-concrete mechanics

为提高混凝土细观力学预处理的效率与骨料投放含量,并适应不同体积、不同骨料含量混凝土的细观数值模拟要求,本文提出了一种新的预处理方法。该方法在骨料投放阶段,首先形成投放区域的背景网格以及对应网格点的状态矩阵,用以进行骨料的投放定位以及骨料间相互侵入的判定,提高了投放的效率和骨料含量;其次,在细观有限元剖分阶段,利用已有的背景网格状态矩阵完成混凝土细观三相介质的坐标生成,简化了预处理过程。同时,采用分级配随机投放的方式,可保证投放的随机性以及级配分布的合理性。实例证明,该方法实现的二维投放骨料含量可达到80%,三维可达到60%,为细观混凝土数值模拟的预处理提供了一种有力的工具。

A new pre-processing approach has been developed to improve the efficiency and the content of random aggregate disposition. Firstly, a background-grid and the corresponding space matrix of the grid nodes are formed in a target region, the matrix is used in the process of distinguishing aggregate positions and judgment of aggregate overlapping, which is able to increase the efficiency and density of aggregate contents. Secondly, the space matrix is used to generate a finite element mesh with three-phase system consisting of aggregate, mortar and interface. The randomness and the aggregate distribution are guaranteed by the way of disposing the aggregates stochastically. It is found that, by using this method the aggregate content may reach 80% in 2-D simulation and 60% in 3-D simulation, thus, the method provides a powerful tool for the pre-processing of finite element analysis.