Ultrasonic evaluation of closed cracks using subharmonic/ superharmonic phased array and a laser interferometer
نویسندگان
چکیده
A new method for detection and sizing of closed crack is described which uses transient waveform of subharmonics with half input frequency in ultrasonic nondestructive evaluation. In analogy to the resonant characteristics of vibration of bubbles in liquids, we formulate an equation for resonant excitation of subharmonics at partially closed cracks. The equation has been partially verified by comparison between experimental and calculated waveforms. An apparatus for imaging closed cracks in critical components such as in atomic power plant SPACE (subharmonic phased array for crack evaluation) and its extension using laser interferometer are proposed.
منابع مشابه
Nonlinear ultrasonic imaging method for closed cracks using subtraction of responses at different external loads.
To improve the selectivity of closed cracks for objects other than cracks in ultrasonic imaging, we propose an extension of a novel imaging method, namely, subharmonic phased array for crack evaluation (SPACE) as well as another approach using the subtraction of responses at different external loads. By applying external static or dynamic loads to closed cracks, the contact state in the cracks ...
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