SENSITIVE ELEMENT FOR ULTRASONIC PIEZOELECTRIC RECEIVING CONVERTER Russian patent published in 2000 - IPC

FIELD: nondestructive inspection of industrial objects, inspection of extended objects and objects with high attenuation of sound. SUBSTANCE: expansion of bandwidth and reduced irregularity of amplitude-frequency characteristic are achieved thanks to insertion of cylindrical piezoelement carrying frequency- lowering cylinder into sensitive element for ultrasonic piezoelectric receiving converter. Their dimensions and resonance frequencies are chosen from conditions: D^pe> H^pe, fpeR

= K₁f₂, fpep= K₂f₂, f₁< fcylp1< fpeR, D^cyl< H^cyl, where f₁ is lower boundary of bandwidth; f₂ is upper boundary of bandwidth; D^pe is diameter of piezoelement; H^pe is height of piezoelement; fpeR is own frequency of radial vibrations of piezoelement; 0.70,7 ≤ K₁< 1 is first empirical coefficient; fpep is own frequency of longitudinal vibrations of piezoelement; 1.51,5 ≤ K₂≤ 2,5 is second empirical coefficient; fcylp1 is first own frequency of longitudinal vibrations of frequency-lowering cylinder; D^cyl is diameter of frequency- lowering cylinder; H^cyl is height of frequency-lowering cylinder. Second own frequency fcylp2 of longitudinal vibrations of frequency-lowering cylinder is chosen from condition fpeR< fcylp2< fpep. Own frequency fcylR of radial vibrations of frequency-lowering cylinder is selected from condition fcylR= (0,9-1,1)fpeR. EFFECT: expanded bandwidth and reduced irregularity of amplitude-frequency characteristic. 4 cl, 2 dwg