二维细观随机混凝土模型的建立和应用

发布时间：2018-03-29 14:24

  本文选题：桥梁工程　切入点：混凝土　出处：《长安大学学报(自然科学版)》2017年03期

【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。
[Abstract]:In order to establish a meso-random concrete model, the concrete is assumed to be a two-phase composite composed of coarse aggregate and cement mortar. According to the types of aggregates commonly used, they are assumed to be circular, elliptical and convex polygon respectively. Two dimensional pebbles and gravel aggregates are randomly dropped, and the corresponding programs are compiled by using MATLAB software. In order to make the stochastic concrete model generated by MATLAB can be called by finite element program and further analyze the physical and mechanical properties of concrete, a fig2dxf program is developed. The graphic file in MATLAB is converted to .dxf format, and the random aggregate model is seamlessly connected with the finite element software. The results show that the established random aggregate model not only meets the equivalence of aggregate volume, but also ensures the randomness of aggregate size. The content of aggregate is high, the random mixture of round and elliptical aggregate is more suitable for randomness and actual situation, the random dropping algorithm of convex polygon aggregate is simple, and the sharp angle of polygon aggregate is skillfully eliminated. Using the commonly used finite element software ANSYS and so on to mesh the generated random aggregate, the standard concrete specimen generated by the established model meets the requirements of the code and can meet the needs of the finite element mesoscopic analysis. It provides a reliable basis for further study of the meso physical and mechanical properties of concrete.
【作者单位】： 长安大学旧桥检测与加固技术交通行业重点实验室;中交第一公路勘察设计研究院有限公司;
【基金】：交通运输部应用基础研究项目(2013 319 812 100) 国家自然科学基金项目(51508027)
【分类号】：TU528
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本文编号：1681528