Research On Pipeline Ultrasonic Testing Data Processing And Defect Recognition Method

Pipeline is an effective transportation equipment for transporting water,crude oil,natural gas and other important energy sources in China.It is used in petroleum,chemical,military,pharmaceutical and other occasions.With the rapid development of pipeline construction in China,some pipelines leak and explosion accidents follow.In the past,it has caused serious damage to people's health,social security,and the environment.Preventing the occurrence of pipeline accidents has become an important engineering issue of great concern.Long-term corrosion,mechanical damage,and external damage cause pipeline defects to be the main cause of pipeline leakage and explosion accidents.The existence of pipeline defects is a decisive factor in determining whether it can be operated safely.Therefore,in order to ensure the safe operation of the pipeline,It is very important to effectively test the pipeline to determine whether the pipeline has defects.This paper studies related issues such as ultrasonic inspection theory,ultrasonic sensor array structure,ultrasonic inspection data acquisition and storage system,noise signal processing and defect identification methods.There are many kinds of defects in the pipeline,such as corrosion defects,cracks,etc.For many defects,in the past,the single incident method of the sensor,that is,the normal incidence method was used for detection.This detection method often misses detection,especially for crack defects.Sensitive,in order to improve the defect detection rate,a combination structure of ultrasonic sensor vertical incidence and oblique incidence is used to detect a variety of defects,and for the problem of the optimal angle of oblique incidence of the sensor,combined with mathematical modeling methods and MATLAB simulation to the sensor The optimal angle of oblique incidence is explored to obtain the optimal angle range of the sensor,and the structure of the ultrasonic sensor probe array is studied.Use the ultrasonic detection device to test the experimental pipeline,and use the host computer ultrasonic internal detection data collection and storage system to collect and store the ultrasonic data.Due to the complexity of the site environment,the collected signal is noisy.The wavelet threshold filter is used to collect the ultrasonic internal detection data The ultrasonic signals collected by the storage system are preprocessed to obtain reliable data.The pipeline ultrasonic inspection system is designed in the LabVIEW development environment,which can display the waveform of the ultrasonic data of the defect and output the thickness value.By analyzing the waveform characteristics of different corrosion defects signals,using the method of time domain feature parameter extraction,the feature parameters that can reflect the defect characteristics are selected in the time domain,and the pipeline corrosion defects are identified by combining the thickness value and the time domain feature parameters.The results show that the combination of multiple incident modes of ultrasonic sensors can improve the defect detection rate.The ultrasonic testing device is used to detect the pipeline to obtain the pipeline information.By comparing and analyzing the thickness values of different defect signals and the time-domain feature parameters in the host computer,the inner wall corrosion and outer wall corrosion defects of the pipeline can be detected and identified.