【作者】 郭福平；

【导师】 李伟；

【作者基本信息】 大庆石油学院 ， 化工过程机械， 2008， 硕士

【摘要】 声发射检测作为一种动态检测技术,不仅能够有效地检测出材料中诸如裂纹扩展、纤维断裂以及其它形式损伤所形成的声发射源,而且能够对泄漏等引起的二次声发射源进行动态监测。在工业生产过程中,应用声发射检测技术对压力容器、管道等设备进行检测时,如果存在高温、深冷、辐射和埋地等特殊工况时,很难把传感器直接安装在被检测对象的表面上。因此,开展波导杆辅助检测工具进行特殊工况条件下的声发射检测技术具有重要意义。本文在对波导杆中声波传播理论研究的基础上,在实验室条件下,研究波导杆的结构型式、波导杆所处的不同介质等因素对声发射检测的影响,并将波导杆应用于管道泄漏的声发射检测。研究结果为波导杆在声发射检测中的应用提供实验依据。本文主要研究以下内容:1.对瞬态弹性波在波导杆中的传播进行理论分析,建立波导杆中传播的声发射弹性波幅度计算的数学表达式;2.分别对三种不同长度、七种不同直径的波导杆对声发射波的影响进行实验研究。研究不同结构型式的波导杆对声源引起的声发射波形和频谱的影响;3.对波导杆在水、油、土壤介质中信号传播特点进行实验研究,通过对波导杆接收声发射信号的幅度分析,研究不同介质中声发射信号的传播特点;4.建立用波导杆辅助检测管道气体泄漏的声发射实验系统,研究带有波导杆管道的气体泄漏声发射检测方法,不同压力、不同直径泄漏孔径下的声发射信号特征。更多还原

【Abstract】 As a dynamic examination technology, acoustic emission inspection can not only effectively examine the developing acoustic emission sources in the materials caused by such as crack spread, fibres rupture and other damnification, but also can monitor two times acoustic emission sources caused by leakage or others. In industrial production process, when pressure vessels and pipelines are inspected by acoustic emission technique, it is difficult to directly stick the sensors onto the surface of the object being examined if there exist such situations as high temperature, deep cold, radicalization, buries etc. Therefore, it is of vital significance to apply wave guide rod as assistant tool in acoustic emission inspection under the special operating condition.Based on the diffusing theory of wave guide rod, under the laboratory condition, the structure pattern of wave guide rod, the influence of different mediums where wave guide rod locates to the acoustic emission inspection and acoustic emission inspection to pipeline leakage using wave guide rod are all included in the paper. The research results provide the experiment gist to the application of wave guide rod in acoustic emission inspection. The contents of the paper are listed as follows:1. Theoretically analyze the diffusing rule of transient state elastic wave in wave guide rod, establish the amplitude mathematical expression of acoustic emission elastic wave diffusing in the wave guide rod;2. Carry experimental research on wave guide rods with three different lengths and seven different diameters. The findings show that the structure of wave guide rods has certain influence on AE waveforms and spectrums when the waves are excited by point sound sources, but for continuous sources, the influence is little;3. Carry experimental research on diffusing rule of wave guide rods in the water, the oil, the soil and analyze the amplitude of AE signals to study diffusing characteristic in different mediums;4. Establish acoustic emission experiment system of examining gas leakage in pipeline using wave guide rod as assistant tool, investigate AE inspection method to examine the gas leakage in pipeline with wave guide rod, finally discuss the characteristic of AE signals under different pressure and different diameter of leaking aperture.更多还原