Design And Research Of Nondestructive Testing System For The Defects On Pipeline Based On Electromagnetic Acoustic

Pipeline transportation industry has become the lifeblood of national development,at the same time,for the pipeline defect detection technology has become a hot research in recent years,especially non-destructive testing technology research continues to progress.Electromagnetic acoustic non-destructive testing technology in recent years gradually gets everyone's attention.With the traditional acoustic testing technology,electromagnetic acoustic non-destructive testing technology has its own unique advantages,the first electromagnetic acoustic testing technology does not require the use of coupling agent,but also do not need to treat the surface of the test pieces of special treatment,simple and quick;Ultrasound can produce a variety of waveforms,there can be a variety of different detection patterns,in the future will be widely used.This thesis will be studied from follow aspects.Firstly,the research results of electromagnetic acoustic technology at home and abroad are summarized,and the mechanism of electromagnetic acoustic transducing mechanism is analyzed,which involves electric field,magnetic field,force field and motion field.Through detailed analysis of mathematical form,a complete conversion process is given equation.At the same time,the different transducers of electromagnetic acoustic transducers are analyzed and studied.Through the discussion of the basic theory of electromagnetic ultrasound,we analyze the working mechanism of the object is clearly studied,and the problems in the research of the system and the relationship between the structure of the device and the acoustic waveform.Secondly,through the experimental and ANSYS finite element simulation of the way,for the improvement of the efficiency of electromagnetic acoustic transducer to explore,because the electromagnetic acoustic transducer conversion efficiency is very low,so the efficiency of the conversion is the system design is a key point The research on the optimized design mainly includes the line spacing of the coil,the extraction value between the coil and the test piece,and the characteristics of the excitation signal.The parameters of the electromagnetic acoustic transducer are analyzed by theoretical analysis,simulation analysis and experimental verification Optimized combination design.Thirdly,we design the electromagnetic acoustic nondestructive testing systems,including excitation power,front rear amplifier circuit,impedance matching circuit design,transducer coil design,and data signal acquisition and storage.Finally,after analyzing and comparing the results of the experiment with those of the simulation,it demonstrates that we could get the consistent results with the experiment from the simulation.Therefore,this simulation is plausible and precise.At the same time,the existing experimental conditions of the laboratory were tested,and the data were analyzed,and the defect identification was analyzed for the waveform characteristics.