混凝土材料宏观力学特性分析的细观单元等效化模型

Meso-element equivalent model for macro-scopic mechanical properties analysis of concrete material

提出了一种混凝土材料宏观力学特性分析的新方法—细观单元等效化模型。该方法从描述混凝土材料的细观尺度入手,采用Monte Carlo法生成由骨料颗粒及砂浆基质组成的混凝土试件的随机骨料模型;然后,依据混凝土材料特征单元尺度来剖分有限元网格并投影到建立的随机骨料模型上,各细观单元的有效力学特性则采用复合材料等效化方法来确定。本文方法体现了材料非线性宏观力学特性源于其内在的不均匀性这一认识,而对不均匀性的描述则是以网格剖分是否影响其宏观力学特性为准则。因此,本文方法较其他细观力学方法最大的优点在于极大地减小了体系自由度数目(特别是对于三维问题),从而提高了计算效率。算例分析初步验证了本文方法的高效性。

A new method,meso-element equivalent model,was proposed in the paper to analyze the macro mechanical properties of concrete materials.The method was described to start with the meso-scale of concrete; the Monte Carlo method was used to generate the random aggregate model of concrete composed of the aggregate particles and the mortar matrix.And then,the finite element grid was meshed based on characteristic element scale of concrete materials,and the mesh grid was projected onto the established random aggregate model.The mechanical properties of every element were determined by equivalence method of composite-materials.The proposed approach reflected the recognition of the macro-scopic mechanical properties of material nonlinearity due to their inherent heterogeneity.While the meso mesh whether affecting the macroscopic mechanical properties of concrete,was taken as the criterion for the non-uniformity description.Hence,comparing with the meso-mechanical method,the excellent advantages of the method was that the system reduced the number of degrees of freedom greatly,which improved the computational efficiency,especially for 3D problems.The examples analysis in the paper confirmed the high efficiency of this method.