基于CT技术的沥青混合料三维重构及数值模拟研究

发布时间：2018-06-30 21:38

本文选题：沥青混合料 + 蠕变试验　；参考：《辽宁工程技术大学》2015年硕士论文

【摘要】：沥青混合料是由沥青砂浆、粗集料和空隙构成的复合材料,近年来随着科学技术的不断提高,对沥青混合料的研究也在不断地深入,从宏观研究逐步走向微观细观。然而沥青混合料是一种非均质材料,而且当前对沥青混合料的研究大部分都是在宏观层面,因此要想对其有深入的研究,必须将外部宏观力学性质与内部细观力学性质充分结合,并进行三维重构及力学模拟试验研究,进而使对沥青混合料的研究更贴近真实。本文首先采用万能试验机结合自编程序,对AC-10、AC-13、AC-16三种不同级配的沥青混合料试件在常温下进行单轴静态蠕变试验,试验结果表明,对同一级配的沥青混合料,所施加的荷载应力越大,沥青混合料变形就较大。对沥青砂浆试件进行了单轴静态蠕变试验,得到沥青砂浆蠕变曲线变化趋势与沥青混合料蠕变曲线变化趋势大致相同,并通过试验数据得到有限元模拟所需要的参数。此外,本文还采用TAW-2000岩石三轴仪对粗集料岩石进行单轴压缩试验,通过计算得到粗集料的弹性模量和泊松比。其次,本文将CT扫描技术和图像处理技术相结合,对沥青混合料的CT扫描试样,得到沥青混合料的不同层图像的内在信息,然后应用Matlab图像处理软件对扫描图像进行图像增强、图像分割和图像的三值化等处理。结果表明,通过图像增强和图像分割后,使图像变得清晰、平滑,而通过双峰法实现三值化后,能将沥青混合料的三部分组成清晰的分开,为三维重构的研究奠定基础。最后,通过医学软件实现了沥青混合料试件的三维可视化,并实现了沥青混合料的三部分组成的分离以及网格的划分和优化,而后将模型导入有限元软件Ansys中,通过Burgers拟合得到所需的不同材料参数并转换为Ansys软件可以识别的Prony级数,对沥青混合料试件进行三维有限元数值模拟研究,并将模拟结果与室内蠕变试验结果进行对比分析,验证了模拟的可行性和准确性,为以后进行虚拟力学试验模拟研究提供了新思路,同时也为工程实际的研究提供了有利的依据。
[Abstract]:Asphalt mixture is a composite composed of asphalt mortar, coarse aggregate and void. In recent years, with the development of science and technology, the research of asphalt mixture is also going deep, from macroscopic research to microscopic research. However, asphalt mixture is a kind of heterogeneous material, and most of the current research on asphalt mixture is at the macro level. It is necessary to combine the external macroscopic mechanical properties with the internal meso-mechanical properties, and carry out three-dimensional reconstruction and mechanical simulation experiments to make the study of asphalt mixture more realistic. In this paper, the uniaxial static creep tests of three kinds of bituminous mixture specimens with different grades AC-10 and AC-13 AC-16 are carried out at room temperature by using universal testing machine and self-programmed program. The results show that the same grade asphalt mixture is used for the same grade asphalt mixture. The greater the load stress, the greater the deformation of asphalt mixture. The uniaxial static creep test of asphalt mortar specimens was carried out, and the creep curve of asphalt mortar was obtained. The change trend of creep curve of asphalt mortar was approximately the same as that of asphalt mixture, and the parameters needed for finite element simulation were obtained from the test data. In addition, the uniaxial compression test of coarse aggregate rock is carried out by TAW-2000 rock triaxial apparatus, and the elastic modulus and Poisson's ratio of coarse aggregate are calculated. Secondly, the CT scanning technology and image processing technology are combined to obtain the internal information of different layers images of asphalt mixture, and then the image enhancement of the scanning image is carried out by using Matlab image processing software. Image segmentation and ternary image processing. The results show that after image enhancement and image segmentation, the image becomes clear and smooth, and the three parts of the asphalt mixture can be clearly separated by using the bimodal method, which lays the foundation for the research of 3D reconstruction. Finally, the 3D visualization of asphalt mixture specimen is realized by medical software, and the separation of three parts of asphalt mixture and the division and optimization of mesh are realized. Then the model is introduced into the finite element software Ansys. Different material parameters are obtained by Burgers fitting and converted into Prony series which can be recognized by Ansys software. The three-dimensional finite element numerical simulation of asphalt mixture specimen is carried out, and the simulation results are compared with the results of indoor creep test. The feasibility and accuracy of the simulation are verified, which provides a new idea for the simulation research of the virtual mechanical test in the future, and also provides a favorable basis for the practical engineering research.
【学位授予单位】：辽宁工程技术大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U414

【参考文献】