管道结构腐蚀损伤声发射监测技术研究

发布时间：2018-06-29 23:55

本文选题：声发射 + 管道结构　；参考：《大连理工大学》2015年硕士论文

【摘要】：管道结构作为一种广泛应用的工程结构,其承担着重要的生产使命,需要长时间服役。管道结构失效破坏,产生严重的负面影响甚至导致灾难发生,保证管道结构的安全意义重大,对管道结构进行健康监测是保证管道工程正常使用的最有效手段。管道结构失效的最主要原因之一是管道腐蚀破坏,其不仅导致管道结构承载能力的降低,甚至还直接导致管道结构的腐蚀穿孔泄漏,是各类管道工程事故防范的重点。本文通过声发射检测技术对管道结构腐蚀损伤进行监测研究,主要的内容包括：(1)开展了钢制管道腐蚀破坏声发射监测实验研究。介绍了管道腐蚀机理,设计了钢制管道加速电化学腐蚀实验,整个实验过程进行了声发射动态监测,获取了管道腐蚀损伤全过程声发射监测信号。通过声发射信号特征参数分析,得出了管道腐蚀声发射信号的特性,并将管道腐蚀过程划分成腐蚀孕育期、腐蚀加速期、腐蚀稳定期、腐蚀基本停滞期四个阶段。通过波形分析,区分出了不同峰频所对应信号的波形特征和频谱。(2)为了确定管道腐蚀损伤不同的声发射源,对管道腐蚀声发射信号进行了聚类分析。首先进行了管道腐蚀声发射信号数据主成分分析,降低了信息冗余量。然后采用K均值算法和模糊C均值算法对管道腐蚀声发射信号进行了聚类分析并进行了比较分析。通过二者的有效性分析确定了最佳聚类类别数。二者对管道腐蚀声发射信号分类识别的结果完全一致,有效识别了管道腐蚀过程中的损伤源和噪声源。根据各类信号的相关特征参数累积曲线,揭示了各类信号的发生发展过程,得到了管道腐蚀损伤源对应的声发射信号类别。(3)利用声发射技术对管道腐蚀穿孔泄漏进行了定位研究。首先研究了管道声发射信号衰减特性,证实声发射信号在钢制管道上传播特性良好。通过模拟天然气管道泄漏过程,设计了高压管道气体泄漏检测和定位实验。分析了不同管道压强下泄漏声发射信号的特征；利用小波分析技术对泄漏信号进行降噪处理,通过互相关函数法对去噪后的泄漏信号进行了时延估计,采用时差定位法对泄漏源进行了定位计算,取得了良好的定位精度。
[Abstract]:As a widely used engineering structure, pipeline structure takes on important production mission and needs long service. The failure and failure of pipeline structure have serious negative effects and even lead to disaster. It is of great significance to ensure the safety of pipeline structure. The most effective means to ensure the normal use of pipeline engineering is to monitor the pipeline structure healthily. One of the main causes of pipeline failure is pipeline corrosion, which not only reduces the bearing capacity of pipeline structure, but also directly leads to corrosion, perforation and leakage of pipeline structure, which is the key point of all kinds of pipeline engineering accident prevention. The main contents of this paper are as follows: (1) the experimental research on acoustic emission monitoring of steel pipeline corrosion damage is carried out. The corrosion mechanism of pipeline is introduced, and the accelerated electrochemical corrosion experiment of steel pipeline is designed. The acoustic emission dynamic monitoring is carried out in the whole process of the experiment, and the acoustic emission monitoring signal of the whole process of pipeline corrosion damage is obtained. By analyzing the characteristic parameters of acoustic emission signal, the characteristics of corrosion acoustic emission signal of pipeline are obtained, and the corrosion process of pipeline is divided into four stages: inoculation period, accelerated period, stable stage and stagnation stage. Through waveform analysis, the waveform characteristics and spectrum of the signals corresponding to different peak frequencies are distinguished. (2) in order to determine the different acoustic emission sources of pipeline corrosion damage, the pipeline corrosion acoustic emission signals are analyzed by cluster analysis. Firstly, the principal component analysis of pipeline corrosion acoustic emission signal data is carried out to reduce the information redundancy. Then K-means algorithm and fuzzy C-means algorithm are used to cluster and compare the corrosion acoustic emission signals of pipeline. The optimal number of clustering categories is determined by the validity analysis of the two methods. The results of classification and identification of acoustic emission signals of pipeline corrosion are consistent with each other, and the damage and noise sources in the corrosion process of pipeline are effectively identified. According to the cumulative curve of the characteristic parameters of all kinds of signals, the occurrence and development process of all kinds of signals are revealed. The acoustic emission signals corresponding to the corrosion damage source of pipeline are obtained. (3) the location of corrosion and perforation leakage of pipeline is studied by acoustic emission technology. Firstly, the attenuation characteristics of acoustic emission signal in pipeline are studied, and it is proved that the acoustic emission signal propagates well on steel pipe. By simulating the leakage process of natural gas pipeline, the gas leakage detection and location experiment of high pressure pipeline is designed. The characteristics of leakage acoustic emission signal under different pressure of pipeline are analyzed, the noise reduction of leakage signal is carried out by wavelet analysis technology, and the time delay of de-noised leakage signal is estimated by cross-correlation function method. The time difference method is used to locate the leakage source, and good positioning accuracy is obtained.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U178

【参考文献】