声发射定位精度及其影响因素试验研究

发布时间：2018-05-13 05:15

本文选题：声发射 + 定位精度　；参考：《重庆大学》2015年硕士论文

【摘要】：对于脆性岩石而言,岩石的破坏过程与其内部微裂纹演化过程是一致的,微裂纹的产生与扩展,伴随着弹性波的释放并在岩石内快速传播,即声发射。声发射信号一般较弱,需要借助于专门的仪器加以监测,利用多个声发射换能器可以实现声发射位置的定位。但是由于声发射信号的复杂性和非平稳性特性,以及岩石试件的形状、尺寸、孔隙度等物理特性的影响,声发射定位的精度较差,因而使得声发射技术的研究和应用受到了很大限制。本文借助于实验室测试分析的方法,研究声发射定位精度的重要影响因素,对于更精确的反演声发射源的信息具有重要的理论意义和实际应用价值。本文运用断铅试验方法通过研究不同试验条件下声发射三维定位的准确度,并对其产生的误差进行分析,在获取大量声发射定位试验数据的基础上,对影响声发射定位精度的各因素进行理论分析及处理,得到更为精确的声发射源定位信息,提高声发射定位的有效性。主要研究成果有:①利用PCI-2型声发射测试系统,开展不同试件尺寸条件下的砂岩声发射断铅定位试验,探讨试件尺寸对定位精度的影响大小,分析试件尺寸与定位误差间的线性规律。②开展换能器距岩石试件边界不同距离条件下的砂岩声发射断铅定位试验,探讨边界效应对声发射定位精度的影响,并结合试件尺寸研究,探讨不同试件尺寸条件下换能器距岩石试件边界的最优距离。③开展不同换能器耦合耦合剂条件下的砂岩声发射断铅定位试验,对比分析不同耦合剂对砂岩定位精度的影响,寻找最适宜的耦合剂以提高声发射定位精度。④开展不同垫板厚度条件下的砂岩声发射断铅定位试验,探讨换能器与砂岩试件间的垫板厚度对声发射定位精度的影响规律,分析声发射换能器与砂岩试件之间垫板的合理厚度。
[Abstract]:For brittle rocks, the failure process of rocks is consistent with the evolution process of microcracks in rocks. The generation and propagation of microcracks are accompanied by the release of elastic waves and rapid propagation in rocks, i.e. acoustic emission. Acoustic emission signals are usually weak and need to be monitored by means of special instruments. The location of acoustic emission can be realized by using multiple acoustic emission transducers. However, because of the complexity and non-stationary characteristics of acoustic emission signal and the influence of physical characteristics such as shape, size and porosity of rock specimen, the accuracy of acoustic emission localization is poor. Therefore, the research and application of acoustic emission technology are greatly restricted. With the help of the method of laboratory test and analysis, this paper studies the important factors that affect the accuracy of acoustic emission location, which has important theoretical significance and practical application value for more accurate retrieval of acoustic emission source information. In this paper, the accuracy of three dimensional acoustic emission localization under different experimental conditions is studied by using lead broken test method, and the errors generated are analyzed. On the basis of obtaining a large number of acoustic emission localization test data, a large number of acoustic emission localization test data are obtained. The factors affecting the accuracy of acoustic emission positioning are analyzed and processed theoretically to obtain more accurate localization information of acoustic emission sources and to improve the effectiveness of acoustic emission positioning. The main research results are as follows: using PCI-2 acoustic emission testing system, the main research results are as follows: (1) using PCI-2 model acoustic emission testing system, the lead broken location test of sandstone acoustic emission under different specimen sizes is carried out, and the influence of specimen size on positioning accuracy is discussed. The linear rule between specimen size and positioning error is analyzed. 2. The acoustic emission lead broken location test of sandstone under different distances from the transducer to the rock specimen boundary is carried out, and the influence of boundary effect on the accuracy of acoustic emission location is discussed. Based on the study of specimen size, the optimum distance between transducer and rock specimen boundary is discussed. 3. The acoustic emission lead broken location test of sandstone under different coupling agent conditions is carried out. By comparing and analyzing the influence of different coupling agents on the positioning accuracy of sandstone, the most suitable coupling agent is found to improve the positioning accuracy of acoustic emission. 4. The lead broken location test of sandstone acoustic emission under different thickness of gasket is carried out. The influence of the thickness of the gasket between the transducer and the sandstone specimen on the accuracy of acoustic emission positioning is discussed, and the reasonable thickness of the gasket between the acoustic emission transducer and the sandstone specimen is analyzed.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU45

【参考文献】