含非规则骨料的混凝土细观建模与分析

发布时间：2018-02-01 10:08

本文关键词： 混凝土数字图像处理分形骨料形态细观数值模型粘弹性　出处：《合肥工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：为了构造能表征真实骨料轮廓形状的骨料二维截面,本文提出三种骨料重构方法,分别为矢径法、分形布朗运动法和双指标法。以双指标法生成的骨料二维截面为例,基于圆度值和SP值指标分析了数值骨料的棱角性特征。生成四个分别包含圆形、方形、规则分形和非规则分形骨料的方形数值试件,建立单轴压缩、单轴拉伸和水平剪切三种加载工况下的数值试验。棱角性和数值试验都表明非规则分形骨料更接近真实骨料。采用双指标法能生成更具有真实特征的非规则骨料轮廓。对于三维数值骨料的生成本文提出了三种方法,分别为网络云计算法、三维随机中点位移法和多骨料截面法。对三种生成方法构造的三维数值骨料进行分析,以体积、圆度、扁平率、纵长比和形状因子指标进行评价。编写骨料投放算法,生成数值试件验证其投放率的合理性。基于内嵌骨料的沥青砂浆冲击试验研究骨料分布对动力学响应的影响。分别生成沥青混凝土和水泥混凝土试件,验证数值骨料分布的力学可靠性。通过对小梁三点弯拉试验的模拟验证界面的力学特性。基于骨料和识别的沥青砂浆的动态模量,通过沥青混凝土的细观结构来预估试件的宏观力学响应。对比三种生成方法发现,多骨料截面法可以生成更接近真实骨料指标的三维数值骨料。通过建模仿真得到的数值计算结果均与试验数据相吻合,说明多骨料截面法、骨料投放算法和界面生成方法均合理有效。仿真结果与试验数据的一致性证明了沥青混凝土细观数值骨料模型可以替代真实试验进行宏观的力学响应分析。沥青混凝土宏观材料参数与细观材料参数的转换公式经验证具有适用性。
[Abstract]:In order to construct two-dimensional cross-section of aggregate which can represent the shape of real aggregate, three methods of aggregate reconstruction are presented in this paper, which are respectively vector diameter method. Fractal Brownian motion method and double index method. Taking the two-dimensional section of aggregate generated by double index method as an example, based on roundness value and SP value index, this paper analyzes the angular characteristics of numerical aggregate. Regular fractal and irregular fractal aggregates of square numerical specimens are established for uniaxial compression. The numerical tests under uniaxial tension and horizontal shearing show that the irregular fractal aggregate is closer to the real aggregate, and that the irregular aggregate with more real characteristics can be generated by using the bivariate method. This paper presents three methods for the generation of three-dimensional numerical aggregate. The three dimensional numerical aggregates constructed by the three generation methods are analyzed by volume, roundness and flatness respectively, which are network cloud computing method, three-dimensional random midpoint displacement method and multi-aggregate cross-section method. The ratio of length to length and the index of shape factor were evaluated. The effect of aggregate distribution on the dynamic response was studied based on the impact test of bituminous mortar embedded in aggregate. The bituminous concrete and cement concrete specimen were formed respectively. To verify the mechanical reliability of numerical aggregate distribution. The dynamic modulus of asphalt mortar based on aggregate and recognition was verified by simulating the three-point bending and tensile tests of trabeculae. The macroscopic mechanical response of the specimens is estimated by the meso-structure of asphalt concrete. The multi-aggregate cross-section method can generate three-dimensional numerical aggregate which is closer to the real aggregate index. The numerical results obtained by modeling and simulation are in agreement with the experimental data, which shows that the multi-aggregate cross-section method. Both the aggregate placement algorithm and the interface generation method are reasonable and effective. The consistency between the simulation results and the experimental data proves that the meso-numerical aggregate model of asphalt concrete can replace the real test to carry out macroscopic mechanical response analysis. The conversion formula of macroscopic material parameter and mesoscopic material parameter of concrete has been proved to be applicable.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528

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