Pliesnetsov S. Development of methods and tools for electromagnetic and acoustic control of rod, tubular and sheet metal products

The dissertation solves a topical scientific and practical problem – the development of theoretical positions and tools for excitation of high-frequency ultrasonic pulses by electromagnetic-acoustic transducers in tubular, rod and sheet metal products with increased sensitivity by increasing the ratio of amplitudes of the useful signal to interference. In the dissertation work the mathematical model of the electromagnetic-acoustic transducer intended for excitation of ultrasonic oscillations in an electrically conductive product is developed for the first time by means of which two problems of electrostatics and the dynamic theory of elasticity for piecewise homogeneous environment are solved. Experimentally constructed diagrams of the direction of the acoustic field and identified the main factors that affect the intensity of ultrasonic pulses excited by the electromagnetic-acoustic transducer. New designs of electromagnetic-acoustic transducers designed to control hardware with different types of ultrasonic waves have been developed. The use of these converters will significantly increase the signal-to-noise ratio. The possibility of excitation of Rayleigh and Lamb surface waves, as well as torsional waves by transducers with an ultrasonic field intensity sufficient for measurements, control and diagnostics, has been experimentally confirmed. The practical significance of the work is as follows: implemented a theoretical model that allows calculations of parameters and characteristics of electromagnetic-acoustic transducers of combined and separate type, developed, performed and tested bench models of electromagnetic-acoustic transducers, which practically implement the theoretical model and prove its effectiveness, developed electromagnetic-acoustic transducers for control of various components of rod, tubular and sheet metal products for different types and stages of production and operation by torsional waves, Rayleigh and Lamb waves on the surface and inside control objects, developed control methods using developed configurations of transducers and practical recommendations on their use, developed and implemented technical solutions aimed at improving the quality and efficiency of the electromagnetic-acoustic method in production.