Research On Key Technique Of Pipeline Monitoring Based On Phased Array Ultrasonic Guided Waves Tomography

Pipeline transportation plays an indispensable role in both the national economy and the life of common people,and in case of any pipeline accident,the country and the society will suffer from huge impacts and losses.Therefore,it is urgently needed to develop a pipeline structure health monitoring technology with high detection efficiency and low monitoring cost to guarantee the safety of pipeline transportation.Compared with the existing pipeline detection technologies,the ultrasonic guided waves detection technology can achieve long-distance detection with a single point of excitation,and the detection range covers the entire section of the pipeline,thereby significantly improving the detection efficiency.The ultrasonic guided waves detection technology combined with phased array technology can also realize the guided waves phase control excitation and multi-zone receiving,enrich the detection means of the guided waves,improve the redundancy of the detection signal,and increase the probability of defect detection.According to the aforesaid background,this paper puts forward the study on the key phased array ultrasonic guided waves pipeline monitoring technology based on magnetostriction.Additionally,the paper is focused on solving key technologies such as the research and development of the phased array ultrasonic guided waves monitoring prototype,and the design of transducer for array ultrasonic guided waves monitoring,developing phased array ultrasonic guided waves pipeline monitoring algorithm and studying the mechanism of action between the monitoring algorithm and pipe defects,and designing the overall solution for phased array ultrasonic guided waves pipeline monitoring system based on magnetostriction.The details of this dissertation were presented as follows:Chapter 1,firstly,the significance of pipeline structural health monitoring is discussed.Then,the existing pipeline structure health monitoring technology is summarized and compared.The research status of ultrasonic guided waves detection and monitoring technology is analyzed.Based on these results,a method of using phased array guided waves is proposed to solve the obstructions we meet in the pipeline monitoring.Chapter 2,firstly,the basic concept and characteristics of guided waves is introduced.Then the principle of guided wave excitation and reception based on magnetostriction effect is described.The frequency dispersion curves exists in the pipe is obtained by using the method of SAFE.Then,a proper mode for pipeline monitoring is found out.Finally,the RAPID tomography technique based on correlation is introduced.Chapter 3,considering the influence of temperature on guided waves propagation,a phased array ultrasonic guided waves pipeline monitoring algorithm based on RAPID tomography technique is proposed.ABAQUS is used to analyze the mechanism of the monitoring algorithm and pipeline defect.The relationship between tomography image quality and defect of different size and position is studied.Chapter 4,the phased array ultrasonic guided waves pipeline monitoring experiment platform is built firstly.Then,the experimental study on the relationship between the ultrasonic guided waves pipeline monitoring algorithm and the defects of different sizes and positions is carried out.Finally,the feasibility of the monitoring algorithm is verified.Chapter 5,according to the monitoring system function goals,a scheme for the monitoring system of phased array ultrasonic guided waves based on magnetostriction is designed,and the monitoring system framework and implementation are introduced in detail.Chapter 6,the main work and conclusion are summarized and the prospect for future research are put forward.