Research Of The Pipeline Defect Detection Technology Based On Electromagnetic Ultrasonic Guided Wave

Pipeline ultrasonic guided wave detection technology with non-contact, no couplingagent and without pretreatment of the workpiece, etc., the actual line-in the form of linedetection, not the point-in the form of point detection, detection of saving time andimproving the detection efficiency and detection devices, low production cost, suitable fornon-destructive testing of metal tubing. In this paper, electromagnetic ultrasonic guidedwave testing transducers and experimental systems, and the corresponding metal pipedetection experiments.This paper studies the longitudinal guided wave propagation characteristics ofcircumferential waves choice in the metal tube and the excitation frequency. By solving thelongitudinal guided wave dispersion equation circumferential waves draw the dispersioncurve analysis guided wave dispersion characteristics and the multi-modal characteristics,study the propagation characteristics of guided waves in the metal pipeline. Based onANSYS finite element simulation of non-ferromagnetic materials in the form ofpropagation of longitudinal guided wave aluminum surface suffered magnitude anddirection of the Lorentz force and the particle displacement cloud, multi-modalpropagation phenomenon exists and attenuation of longitudinal guided waves in thepipeline phenomenon. COMSOL simulation based on the finite element analysis offerromagnetic materials in the form of longitudinal guided wave propagation, steel surfacesuffered magnetostrictive force magnitude and direction, cloud and particle displacementdirection, as well as cracks in different sizes for longitudinal guided wave magnetostrictiveforces suffered the impact of changes in the form and spread. Simulation to determine thestructural parameters of the transducer, and the longitudinal guided wave transducers usedin aluminum, steel crack defect detection experiments.Conduct experiments on the propagation characteristics of aluminum tubes,transducers inspired modal number increases with increasing frequency, L (0,1) modaldispersion phenomena occurring in the communication process, and L (0,2) non- dispersive mode. Respectively, on the pipe depth of0.5mm,1mm,1.5mm,2mm for thefour comparative experiment defect; the circumferential lengths of40mm,50mm,60mmdefects were compared in three experiments. In case of defective longitudinal guided wavemode conversion is generated, the transducer receives the echo signal amplitude with thedefect depth, length increased with increasing that longitudinal guided wave pipecircumferential cracks in enhanced ability to identify defects echo the amplitude of thedefect size can be characterized. Large diameter steel pipe according to the circumferenceof the experiment, the relationship between the received echo time and velocity of thethree weeks between the wave guide validated in combination with a horseshoe-shapedpermanent magnet excitation coil winding circumferential waves correctness.