中文摘要：

为了建立细观随机混凝土模型,将混凝土假定为由粗骨料和水泥砂浆组成的两相复合材料,根据常用骨料的类型,将其分别假定为圆形、椭圆形、凸多边形3种截面形状,分别给出了二维卵石和碎石骨料的随机投放算法,并利用MATLAB软件编制了相应程序,从而实现了细观层次随机混凝土模型的数值计算。为了使MATLAB生成的随机混凝土模型能被有限元程序调用,并对混凝土物理力学性能作进一步分析,研制了fig2dxf程序,将MATLAB中图形文件转换为.dxf格式,实现了随机骨料模型与有限元软件的无缝对接。研究结果表明：建立的随机骨料模型既满足骨料体积的等效性,又保证了骨料粒径的随机性,骨料含量水平较高;圆形和椭圆形随机混合骨料更符合随机性要求和实际情况;凸多边形骨料随机投放算法简单,同时巧妙地消除了多边形骨料的尖角;利用常用的有限元软件ANSYS等对生成的随机骨料进行网格划分的效果较好;用建立的模型生成标准混凝土试件符合规范要求,并能满足有限元细观分析的需要,为进一步研究混凝土细观物理、力学性能提供了可靠基础。

英文摘要：

In order to establish a mesoscopic stochastic concrete model, concrete was assumed as a two-phase composite material consisting of coarse aggregate and cement mortar. According to common aggregate type, aggregate cross section shape was assumed to be round, oval and convex polygon. Random packing algorithm of 2D pebble and crushed stone aggregate was established, and corresponding program was compiled by using MATLAB software, thus numerical calculation of meso-level stochastic concrete model was established. To make stochastic concrete model generated by MATLAB be called by finite element programs, so as to conduct further analysis of physical and mechanical properties of concrete, a program called fig2dxf was developedand graphic files in MATLAB was converted into . dxf format. Thus, seamless connection between stochastic aggregate model and finite element software was realized. The results show that stochastic aggregate model generated in this paper satisfies the equivalence of aggregate volume, and ensures the randomness of aggregate particle size. Content of aggregate reaches a high level. Circular and elliptic stochastic mixed aggregate models are more in accord with randomness requirements and actual conditions. Random packing algorithm of convex polygon aggregate is simpler, and skillfully eliminates the sharp angles of polygon aggregate. Mesh generation of stochastic aggregate can be carried out through finite element software such as ANSYS and good results are obtained. Standard random concrete specimens generated by this model conform to the specification requirements, and satisfy the needs of finite element analysis. The research results provide reliable basis for further analysis of meso-level physical and mechanical properties of concrete. 1 tab, 11 figs, 22 refs.