Ultrasonic Phased Array Defect Detection Simulation Considering Sound Attenuation And Dispersion Characteristics Of Polyethylene

In the era of carbon neutrality and carbon peak,polyethylene pipeline is superior to metal pipeline in production,operation,energy consumption and maintenance costs in addition to good service performance,and the demand for polyethylene pipeline is still increasing.Ultrasonic phased array testing technology,as a more advanced nondestructive testing method,has the advantages of convenience,no safety protection,intuitive imaging,etc.,has become the preferred method to evaluate the quality of polyethylene pipeline.Ultrasonic phased array detection defect simulation technology can simulate the imaging results of ultrasonic phased array detection of defects,which has important guiding significance to identify the types of defects in actual detection images.However,at present,the ultrasonic phased array inspection flaw of general simulation technology failed to consider the scattered by the acoustic attenuation and audio at the same time,considering the ultrasonic signal multiple reflection and transmission in the process of testing,the accuracy of the simulation results is low,and the simulation technology can only simulate the geometrical morphology defect detection results of the rules of the applicable scope is small.This paper is supported by the "Foal Eagle Program" cultivation Project(Grant No.: CY2022002)and the Yada Plastic Products Co.,LTD.(Project No.: The influence mechanism of sound attenuation and dispersion on ultrasonic phased array detection,the simulation model of defects in polyethylene ultrasonic phased array detection,and the simulation effect of the model on irregular defects and multiple echoes of ultrasonic signals are studied.The main works are as follows:(1)A numerical calculation method is proposed to analyze the influence mechanism of sound attenuation and dispersion characteristics of polyethylene on phased array detection.By comparing the waveform differences of the three cases,which only sound attenuation is variable,only phase velocity is variable,and both sound attenuation and phase velocity are variable,it is determined that with the increase of detection distance,the frequency spectrum of PE will gradually move to the low frequency.The dispersion of PE audio frequency will gradually lead to the aggregation of signal energy in forward half waveform.Taking the complex frequency detection signal with a center frequency of 2.0MHz and a-6d B bandwidth of 50% as an example,the phased array focus synthesis signal under three conditions is compared.The results show that the maximum effective range of the two methods is less than 14 mm and 22 mm when only acoustic attenuation is used as variable or only phase velocity is used as variable to simulate the defects of PE phased array detection.The influence of acoustic attenuation and acoustic dispersion must be considered when simulating the ultrasonic phased array defect detection of thicker polyethylene pipes.(2)The single-frequency ultrasonic wave equation considering the sound attenuation and dispersion characteristics of polyethylene is derived.By decomposing the composite frequency ultrasonic signal into multiple single-frequency signals,the propagation law of each single frequency signal is calculated and superimposed,which is equivalent to the propagation law of composite frequency signal.On this basis,the simulation results of ultrasonic phased array detection of hole defects with or without considering the sound attenuation and dispersion characteristics of PE are compared.The results show that the simulation results are closer to the test results when considering the sound attenuation and dispersion characteristics of PE,and the amplitude deviation of hole defects at the depth of focus is 11.77%.(3)The simulation effect of the defect simulation method on irregular defects and multiple echoes was explored.For irregular defect,select the elliptical defects as the research object,compared with different length to diameter ratio phased array of elliptic defect detection experimental results and simulation results,the defects in the simulation can simulate different length to diameter ratio of elliptic defect phased array inspection imaging differences and pseudo as features,and can pass the level of defect imaging size reflects the actual size of elliptic defect.For multiple echo,the resistance wire imaging features as the main research object,through the simulation of the single resistance wire and specifications for dn63 automtic polyethylene fused joint phased array detection results,shows that defect simulation method to simulate the ultrasonic signals of multiple reflection and transmission within the resistance wire,and can accurately simulate the fused joint phased array in the resistance wire imaging features of the test results.