考虑非均质特征界面的混凝土材料破坏机理精细化分析及应用

项目名称： 考虑非均质特征界面的混凝土材料破坏机理精细化分析及应用

项目编号： No.51478108

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 建筑环境与结构工程学科

项目作者： 郭小明

作者单位： 东南大学

项目金额： 84万元

中文摘要： 研究发现微细观结构显著影响混凝土宏观力学行为。针对细观非均质结构特征与混凝土失效破坏行为间的关系，以建立混凝土精细化分析模型为目标，系统开展理论分析、实验研究和数值模拟。从混凝土非均质复合模型的生成出发，采用广义特征值算法，求解包含非均质、变厚度界面过渡区的粗骨料随机分布问题，构建满足体积分数和级配要求的混凝土几何模型。引入位移模式的损伤本构表征方法，探讨不依赖于网格尺寸的混凝土损伤全过程分析方法，综合运用多尺度网格技术，编制接口程序，发展几何建模和力学分析一体化的求解技术，建立更接近真实状态的混凝土材料计算模型。研制刚度可控加载系统，结合图像采集及灰度相关性分析系统，实现细观裂纹的动态观测，进而验证和修正一体化分析模型。依据一体化模型，分析界面过渡区、基质以及骨料等单一和多重物理力学因素与混凝土宏观强度间的定量关系，构建混凝土失效破坏的概率统计模型，为科学评估混凝土结构的安全性提供基础。

中文关键词： 混凝土；微结构；力学性能；寿命预测；物理性能

英文摘要： Many studies found a significant effect of micro-structure properties on the macroscopic mechanical behavior of concrete. A refinement analysis model is proposed to establish a quantitative relations between heterogeneous meso-structural properties of concrete and its localized damage mechanism. Synthetically combining of theoretical analysis, experimental study and numerical simulation will be tackled to develop the proposed model. A heterogeneous composite model of concrete will be constructed. Generalized eigenvalue algorithm will be utilized to establish a more accurate geometric model of course aggregates satisfying real constrains of volumetric ratios and grading ratios, where mechanical properties of interfacial transfer zones around course aggregates are heterogeneous and their thicknesses are various with aggregates dimensional size. Displacement type of damage evaluation equations will be developed to reduce mesh sensitivity in numerical procedures. By Interface Program, the developed damage evaluation equations will be combined with multi-scale meshing method, and an integration model of concrete will be developed encompassing functions of preprocessing and computing. With the developed integration modeling technology, we will establish a geometrical and physical model closer to the real state of the concrete material. A rigid loading system will be exploited to study the dynamic failure procession of concrete with controlling displacement increment. Using grey-scale correlation analysis, a theory of image processing will be established to detect the crack tip and to measure the whole paths of dynamic cracks. With comparison of measured information by the dynamic crack test system and computed results, the developed integration model will be verified and validated. With the modified integrating concrete material model, we will quantitatively analyze the affections of interfacial transfer zone, mechanical properties of cementations, and geometric distribution of coarse aggregates on concrete apparent strengthen. Furthermore, coupling effects of these factors on concrete apparent strengthen will be analyzed. Failure modes of concrete under typical meso-structural characteristics will be simulated, and a statistics failure model of concrete will be constructed with probability theory. A more scientific model for evaluating security of concrete structures could be obtained.

英文关键词： concrete;micro-structures;mechanical properties;damage prognosis;physical properties