Research On Defect Detection Method Of Phased Array Ultrasonic Guided Wave Pipeline

As one of the five major modes of transportation,pipeline transportation plays an important role in the national economy.In recent years,with the rapid increase of pipeline quantity and the continuous extension of service time in China,Pipeline leakage accidents caused by aging,corrosion and scouring of transportation medium of pipeline materials often occur,which will not only lead to waste of raw materials and products,but also may bring heavy casualties and serious environmental pollution,which has attracted great attention from government management departments and pipeline industry.Therefore,it is of great practical significance to study the detection methods of pipeline corrosion,thinning and other defects.This paper is based on the ultrasonic guided wave detection theory,and he method combines theoretical analysis with numerical simulation to study the pipeline defect detection method based on phased array ultrasonic guided wave.The research content mainly includes three parts: modeling and simulation,data extraction and processing,and three-dimensional imaging of pipeline defects.Firstly,the simulation model of pipeline is established based on comsol finite element simulation software,and the echo signal data of the guided wave is obtained.In order to solve the problem of signal attenuation,this paper adopts phased array and delayed focusing method to effectively change this situation,the parameter setting method of delayed focusing is also studied,and the feasibility of delayed focusing method is verified by simulation.Secondly,after obtaining the data of the guided wave signal under the default non-interference background,firstly,the influence of defects of different sizes on echo signals is studied,and relevant conclusions are obtained;then,by changing the temperature parameters,the influence of temperature change on the detection results is studied,and the influence law of temperature change on wave velocity is given.After correction,the defect location accuracy meets the requirements.Finally,the guided wave signals obtained by phased array elements are transformed into full matrix data by data processing,and the amplitude data are transformed into imaging color data by matlab function,Because the imaging effect does not meet the requirements of defect location,a full focus algorithm is added,and the processed image can complete the defect location in the two-dimensional plan.Then,the pipeline 3D imaging platform is designed by using the graphical user interface(gui interface)of matlab,After inputting pipeline parameters and adding defect data,three-dimensional visualization images of pipelines and defects can be automatically generated,and human-computer interaction function is realized,which provides new ideas and methods for later related research.From the point of view of nondestructive testing of pipeline defects,this paper starts with the excitation mode of guided wave signals,and obtains defect echo data under different backgrounds by changing environmental parameters and defect sizes.