Romaniuk M. Theoretical basis of ultrasonic paths calculating for control devices of metal rolled surface

The thesis is deals with such scientific and applied tasks: the development of effective methods of electroacoustic transducers calculation used in non-destructive testing of sheet metal surface. The characteristics of the excitation and reception of ultrasonic waves transducer of contact and contactless types in a given frequency range - are the main problems which were considered . Two types of typical design transducers used for nondestructive testing of sheet metal - piezoelectric (PET) and electromagnetic-acoustic (EMAT) transducers were investigated. The signals convert algorithms in the modes of excitation and registration of ultrasonic waves in the metal layer were described, the definition of mathematical models for these types of transducers was formulated, the features of the elastic waves propagation in polarized ferromagnetic and piezoelectric were investigated. The basic boundary value problems whose solutions determine the frequency response (mathematical models) of contact and contactless types transducers were formulated.