基于细观层次再生混凝土二维有限元模型研究

发布时间：2018-02-11 09:39

本文关键词： 细观层次再生混凝土随机骨料模型数字图像模型有限元　出处：《新疆大学》2017年硕士论文　论文类型：学位论文

【摘要】：基于宏观层次将再生混凝土材料看作均质同一材料,进行大量的试验对其进行研究,试验过程中受到条件、环境、物力、人力、财力等因素的影响,很多情况下试验开展存在困难,且宏观研究不能完全合理地解释再生混凝土裂纹扩展、应力应变特征及损伤演化规律等问题,因此,需从细微观角度进一步研究,解决宏观上存在问题,目前细观数值模拟方法是再生混凝土细观研究中一种有效可行的方法,但缺乏成熟的细观有限元分析模型,本文以再生混凝土二维细观骨料模型展开研究,论文主要工作及结论有以下四点:(1)基于再生混凝土的再生骨料和原生骨料形态和分布的随机特性,运用蒙特卡罗方法、随机数产生原理、富勒级数和瓦拉文公式等相关理论基础,根据课题组前期大量试验工作,应用ANSYS软件APDL参数化语言编程,编写符合其特点和要求的通用算法流程和命令流。根据骨料分布特征,建立了两种形状骨料的再生混凝土二维随机模型,即:圆形和多边形。通过不同骨料填充颗粒数(25颗、50颗、75颗和100颗)、不同再生骨料掺量(0%、25%、50%和75%)和不同随机次数(4次)三个变量参数对两种随机骨料模型流程算法进行验证。(2)根据数字图像处理技术在工程中应用成功实例和前人对再生混凝土性能研究工作基础,本文建立了一种新的细观骨料模型主要运用“三种软件,两种手段”一数字图像骨料模型。数字图像骨料模型建立过程中骨料分布图像来源于再生混凝土试块切割和提取处理,根据再生混凝土数字图像骨料模型流程建立了三种再生粗骨料掺量(0%、30%和50%)的细观骨料有限元模型。(3)根据课题需要,试验设计了三组再生骨料掺量试件:0%、30%和50%,配合比设计、试块养护等按照试验标准进行试验。测得三项工作,即:立方体抗压强度、破裂过程及应力应变变化曲线。研究了再生粗骨料的掺量和形状两个变量对再生混凝土强度的影响,分析其影响机理。(4)运用三种模型创建算法及流程,建立了满足试验要求的三种细观骨料模型,模拟了不同再生骨料掺量的三组立方体抗压试验的应变变化云图、宏观力学响应和裂缝形态发展过程,通过上述所有分析,从模型生成过程、模型模拟结果和模型优缺点等方面对三种模型进行对比分析,认为再生混凝土更具有推广意义的模型—再生混凝土随机多边形细观骨料模型,最后通过其他研究学者相关数据及数值模拟结果对该模型进行对比,结果基本符合试验结果。
[Abstract]:Based on the macro level will be the same as the recycled concrete material of homogeneous materials, a lot of tests to study, by the conditions in the process of test environment, material resources, human resources, influence and other factors, many cases are difficult to carry out the test, and the macro research can not fully explain the recycled concrete crack propagation, stress the problem, stress strain characteristics and damage evolution etc. Therefore, from the micro angle of further research, to solve the problems on macroscopic, mesoscopic numerical simulation method at present is recycled concrete meso research in an effective and feasible method, but the lack of mature micro finite element analysis model, this paper conducted a study on recycled concrete two dimensional micro aggregate model, the main work and conclusions are the following four points: (1) the random characteristics of recycled concrete aggregate and the original aggregate morphology and distribution based on the use of Mongolia Monte Carlo method, random number generation principle, relevant theoretical basis and besides Fuller series formula, according to previous experimental work, the application of ANSYS software APDL parametric programming language, compile general algorithm and command in accordance with the characteristics and requirements of the aggregate flow. According to the distribution characteristics of a two-dimensional stochastic model of recycled concrete, two the shape of aggregate: circular and polygon filling. Through different aggregate particle number (25 teeth, 50 teeth, 75 teeth and 100 teeth), different amount of recycled aggregate (0%, 25%, 50% and 75%) and different random number (4) of three variable parameters to verify two kinds of random aggregate model of process the algorithm. (2) according to the digital image processing technology and the previous successful application in engineering research work based on the properties of recycled concrete, this paper established a new micro aggregate model mainly uses three kinds of software, two kinds of hand "A digital image. Digital image aggregate aggregate model model of distribution of the image source aggregate in recycled concrete specimens of cutting and extraction, three kinds of recycled coarse aggregate quantity is established based on the digital image process of recycled concrete aggregate model (0%, 30% and 50%) of the micro aggregate finite element model (3). According to the need of the subject, design three groups of recycled aggregate specimens: 0%, 30% and 50%, mix design, test block curing test according to test standard. The measured three tasks, namely: compressive strength, rupture process and stress-strain curve. The effect of recycled coarse aggregate the content and shape of two variables on the strength of recycled concrete, analyzing the influence mechanism. (4) using three kinds of models to create algorithms and processes, is developed to satisfy the test requirements of the three micro aggregate model, simulate the amount of recycled aggregate The strain variation of three groups of cube compressive test, macro mechanical response and crack shape development, through all of the above analysis, generated from the model, simulation results and model advantages and disadvantages on the comparative analysis of three models, that recycled concrete has the significance of popularizing model of recycled concrete meso random polygon aggregate model finally, by other researchers related data and numerical simulation results of the model comparison results are consistent with the experimental results.

【学位授予单位】：新疆大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528

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