考虑骨料随机分布时水泥基材料等效力学参数的分析

发布时间：2018-04-30 00:07

本文选题：骨料随机分布 + 渐近均匀化方法　；参考：《湘潭大学》2017年硕士论文

【摘要】：水泥基材料是工程建设中应用极为广泛的一类复合材料,其中混凝土、砂浆是最常见水泥基材料,水泥基材料的力学参数对其力学性能以及工作性能有密切关联。计算水泥基材料等效力学参数的关键之一是计算水泥基复合材料的等效弹性模量。渐近均匀化方法(Asymptotic Homogenization Method,简称AHM)是一种求解复合材料等效弹性模量的多尺度数学方法,本文以实验数据为建模依据,建立了考虑三维随机骨料分布代表体积单元(Representative Elementary Volume,简称RVE),从细观力学尺度,采用AHM计算了水泥基材料等效弹性模量,并对水泥基材料等效力学参数的影响因素进行了研究。本文的研究内容和主要结论如下:(1)基于已有实验中骨料级配与基体几何信息及力学参数建立了骨料随机分布三维RVE,采用渐近均匀化分析计算出RVE的等效力学参数,等效力学参数与已有经典文献实验结果吻合。(2)分析了颗粒级配对水泥基材料等效力学参数的影响。建立了在同一体积率下,骨料粒径分布分别服从正态分布与均匀分布的三维RVE,并计算出各自的等效力学参数,两种分布下的计算结果差异不显著。(3)分析了水泥基材料的本构关系对构件力学性能的影响。分别计算材料本构关系为各向同性与各向异性的情况下,混凝土板在自重与均布荷载作用下的应力应变等力学性能的区别。在考虑材料各向异性时,构件应力应变以及变形均小于各项同性的情况,但差别不显著。
[Abstract]:Cement based materials are widely used in engineering construction, in which concrete and mortar are the most common cement based materials. The mechanical parameters of cement based materials are closely related to their mechanical properties and working properties. One of the keys to calculate the equivalent mechanical parameters of cement based materials is to calculate the equivalent elastic modulus of cement based composites. Asymptotic homogenization method A symptotic Homogenization method (AHM) is a multi-scale mathematical method for solving the equivalent modulus of elasticity of composite materials. In this paper, the experimental data are used as the basis for modeling. In this paper, the equivalent elastic modulus of cement-based material is calculated by using AHM from the meso-mechanical scale considering the representative Elementary volume unit of three-dimensional random aggregate distribution, and the influencing factors of the equivalent mechanical parameters of cement-based material are studied. The contents and main conclusions of this paper are as follows: (1) based on the geometric information and mechanical parameters of aggregate gradation and matrix in previous experiments, the random distribution of aggregates is established, and the equivalent mechanical parameters of RVE are calculated by asymptotic homogenization analysis. The effect of particle gradation on the equivalent mechanical parameters of cement-based materials was analyzed. Three dimensional RVEs with normal distribution and uniform distribution were established for aggregate particle size distribution at the same volume rate, and their equivalent mechanical parameters were calculated. The effect of constitutive relation of cement-based materials on the mechanical properties of structural members was analyzed. When the constitutive relation of material is isotropic and anisotropic, the difference of mechanical properties of concrete slab under self-weight and uniformly distributed load is obtained. When anisotropy is considered, the stress, strain and deformation of the member are smaller than that of each other, but the difference is not significant.
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528

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