电学层析成像技术在混凝土探伤中的应用研究

发布时间：2018-01-22 02:41

本文关键词： 电学层析成像图像重建混凝土无损检测　出处：《济南大学》2016年硕士论文　论文类型：学位论文

【摘要】：电学层析成像是一种无损检测的成像技术,由于其具有非侵入性(无损)、价格低廉、响应速度快、无放射性以及检测结果直观等特点,在多相流检测、医学、火焰检测、冻土监测等领域得到了良好的应用。但是电学层析成像技术在混凝土结构损伤检测中鲜有报道。本文将电学层析成像技术应用于混凝土结构损伤检测中。通过对混凝土施加电流激励,通过数据采集系统采集携带混凝土内部电导率分布的边界电压值,通过图像重建算法对其内部结构进行成像,主要工作如下:1.开发设计了电学层析成像的数据采集系统。该系统是基于NI公司开发生产的PXI平台,并采用LabVIEW语言编写了数据采集控制程序,此系统可以在保证高采样精度的同时,简便的实现切换激励电极和采集边界电压,同时将数据送入图像重建计算机。2.对电学层析成像重建算法进行了研究,通过仿真实验以及实验研究了五种图像重建算法的优劣,最终选取了改进的归一化图像重建算法,此外基于MATLAB的GUI平台编写了电学层析成像系统的界面,方便于数据管理与图像重建。3.搭建了电学层析成像系统,并以水体为对象进行成像实验探讨此成像系统的可行性,实验结果表明所搭建的电学层析成像系统是适用的。4.通过所搭建的电学层析成像系统实现了对混凝土结构的损伤检测,首先实现了对混凝土结构中损伤(孔径)的成像监测,其次实现了对混凝土中钢筋的探测,包含锈蚀前以及锈蚀后的成像监测,最后实现了对混凝土中海水渗透扩散的成像监测。
[Abstract]:Electrical tomography is a nondestructive imaging technology. Because of its non-invasive (non-invasive, low cost, fast response, non-radioactivity and intuitive test results, etc.), it is used in multiphase flow detection, medicine and so on. Flame detection. The field of frozen soil monitoring has been well applied, but the electrical tomography technique is seldom reported in the damage detection of concrete structure. In this paper, the electrical tomography technique is applied to the damage detection of concrete structure. The concrete is excited by electric current. The boundary voltage of conductivity distribution in concrete is collected by data acquisition system, and its internal structure is imaged by image reconstruction algorithm. The main work is as follows: 1. A data acquisition system for electrical tomography is developed and designed. The system is based on the PXI platform developed by NI Company. The program of data acquisition and control is compiled by LabVIEW language. This system can easily switch the excitation electrode and collect the boundary voltage while ensuring high sampling accuracy. At the same time, the data is sent to the image reconstruction computer. 2. The electrical tomography reconstruction algorithm is studied, and the advantages and disadvantages of the five image reconstruction algorithms are studied by simulation experiments and experiments. Finally, the improved normalized image reconstruction algorithm is selected. In addition, the interface of electrical tomography system is compiled based on the GUI platform of MATLAB. It is convenient for data management and image reconstruction. The electrical tomography system is set up, and the feasibility of this imaging system is discussed by taking the water body as the object of the imaging experiment. The experimental results show that the electrical tomography system is applicable. Through the electrical tomography system, the damage detection of concrete structure is realized. Firstly, the image monitoring of damage (aperture) in concrete structure is realized. Secondly, the detection of steel bars in concrete is realized, including the imaging monitoring before and after corrosion. Finally, the imaging monitoring of seawater permeation diffusion in concrete is realized.
【学位授予单位】：济南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TU317;TP391.41

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