The Simulation Analysis And Experiment Research Of Electromagnetic Ultrasonic Excitation System

Electromagnetic ultrasonic is a new type of nondestructive testing technology, it hasbecome one of the main methods in the nondestructive testing. Electromagnetic acoustictransducer can produce acoustic wave with a variety of types and different characteristics,such as S-wave, longitudinal wave and surface wave etc. This paper focuses on the surfacewave characteristics. We analysis of the equation of surface waves, including the basicequation of electromagnetic ultrasonic, magnetic field equation of permanent magnet,electromagnetic field equation of EMAT, pulsed eddy current field equations and lorentzforce equation and the surface of the lorentz force excitation wave equation.Aimed at the advantages and disadvantages of electromagnetic ultrasonic testingtechnology, the paper focuses on study on the mechanism of electromagnetic ultrasonictesting technology by using the finite element simulation method, and the theoreticalanalysis results are verified through the experimental analysis, and the main researchcontents is the surface wave excited by winding coil.Electromagnetic ultrasonic transducer divided into the energy conversion process ofelectromagnetic field into a force field and the energy conversion process of Lorenz forceexcites the ultrasonic. In the first process is mainly through the establishment of model andANSYS analysis of electromagnetic super transducer on the aluminum plate of themagnetic field and the force characteristic. In the second process will loading the force ofthe first process to the skin layer of permanent magnet on the aluminum plate, analysis ofthe propagation characteristics the attenuation characteristics and directivity of surfacewave in the aluminum plate, special analysis of the displacement near the defect cavity,focus on the influence of defects on surface wave propagation process.According to the magnetic field and the acoustic field characteristics obtained bysimulation, on the basis of theoretical analysis, design of several groups of the coilexcitation system of electromagnetic ultrasonic, select the appropriate coil throughexperimental comparison, through the consistent of analysis of the results ofelectromagnetic ultrasonic experiment and simulation.