E. V. Golubev

On the theory of Lamb wave excitation in metals by pulsed laser radiation

The problem of pulsed photoacoustic transformation is solved for ferromagnetic metal plates. The effect of the temperature dependence of the thermal coefficient of linear expansion on the spectrum of Lamb waves excited by pulsed laser is revealed.

Analysis of ultrasonic waves excited in a metal plate by nanosecond laser pulses

Laser excitation of ultrasonic waves in ferromagnetic plates has been experimentally studied. The obtained results can be recommended for use in the development of methods and equipment for testing thin-walled metal articles.

A photothermal emitter and an EMA receiver of ultrasonic Lamb waves

Results of an investigation into the general characteristics of ultrasonic Lamb waves that are excited by a photothermal emitter in metallic plates as a function of its geometric and energy parameters are given. A metal surface area heated during irradiation by nanosecond optical pulses is such an ultrasonic emitter. Excited Lamb waves were recorded using a special wide-band EMA receiver. These findings can be used in the development of devices for the noncontact ultrasonic quality control of thin metalware.

Experimental study of directional characteristics of a pulsed laser thermoacoustic radiator

Results of experimental research on revealing the dependence of directional characteristics of a pulsed laser thermoacoustic radiator of body ultrasonic waves on the radiator’s energy and geometry parameters are provided. Experimental bench and measurement procedure are described. The results can be used in developing tools for noncontact ultrasonic inspection of metal materials and products.

Studying the temperature dependences of the parameters of laser-generated lamb waves

The process of laser generation of pulses of symmetrical and antisymmetrical Lamb waves in a ferromagnetic plate due to the thermoelastic effect was experimentally studied. The temperature dependences of the shape, amplitude, duration, and vibration frequency of acoustic pulses and the velocities of their propagation in the plate were investigated.

Thickness Gauging of Thin Metalware with Ultrasound Excited by Laser Nanopulses

It has been established that an ultrasonic pulse is split when Lamb ultrasonic waves are excited in thin metalware by a thermosonic emitter 3 mm or more in diameter. This makes it possible to measure the group velocity of ultrasonic waves. A technique is proposed for thickness gauging of articles based on the dependence of the velocity on the vibration frequency and article thickness (dispersion curves).

Directional Characteristics of a Laser Pulsed Thermoacoustic Emitter in Nonmagnetic Metals

Results of experiments on studying the dependence of the directivity of a pulsed laser thermoacoustic emitter of longitudinal and transverse ultrasonic waves that operates in a nonmagnetic conducting medium on the surface density of laser-radiation heat power are presented. The results can be recommended for nondestructive testing of nonmagnetic materials and articles with laser ultrasonic sources.

Influence of the properties of a ferromagnetic metal on the spectrum of Rayleigh waves excited by pulsed laser radiation

A solution to the problem of laser generation of Rayleigh wave pulses in ferromagnetic metals is theoretically studied. The spectra of acoustic pulses are determined in the thermoelastic approximation taking into account a finite value of the heat-flux relaxation time, the metal absorption coefficient, and a change in the thermal linear expansion coefficient. An estimate is obtained for the maximum excess temperature in a half-space upon absorption of an optical pulse.

Experimental studies of laser excitation of normal acoustic waves in ferromagnetic metals at the curie temperature

Laser excitation of normal (Lamb) waves in ferromagnetic plates and the effect of magnetic phase transition on their main characteristics—amplitude, vibration frequency, and propagation velocity—are studied experimentally.

Experimental Investigations into Laser Generation of Surface Acoustic Waves in Ferromagnetics

The effect of magnetic phase transition on the parameters of high-temperature conversion of pulse laser radiation into the acoustic field of surface waves (SAWs) was studied. For this purpose, an experimental setup was designed and assembled.