SELECTIVE ACOUSTIC EMISSION CONVERTER OF ELASTIC WAVES Russian patent published in 2013 - IPC H04R17/00 

FIELD: physics.

SUBSTANCE: selective acoustic emission converter of elastic waves with a circular beam pattern on a plane or scanning of a curvilinear sheet structure includes a circular piezoelectric element, the surface of which is formed by rotating a plane figure in form of a convex polygon with at least four sides around an axis perpendicular to the base of the piezoelectric element, with a working electrode deposited thereon. The converter includes an acoustic unit which includes said circular piezoelectric element, which is in form of a finite cylinder or a truncated cone, with the inclination angle of the lateral surface to the base of not more than 90°, and a protector prism inserted into the circular piezoelectric element and interfaced on the shape with its inner working surface, the material of which has longitudinal wave speed less than the propagation speed of the selected mode of normal waves. The working electrode is deposited on the inner surface of the circular piezoelectric element.

EFFECT: design of a selective ultrasonic converter of acoustic emission signals with a circular beam pattern in the scanning plane of the surface of the control object, which provides selective radiation and reception of the most informative high-amplitude modes of normal waves in order to increase accuracy of locating growing defects and increase reliability of evaluating the degree of hazard thereof.

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