| 摘要 |
The subject invention is a method and apparatus for detecting a flaw in a metallic structure which utilizes a plurality of electromagnetic acoustic transducers located in close proximity to, but spaced from, the metallic structure. Each transducer includes a plurality of magnets located in a spaced apart arrangement. The magnets of one transducer are not aligned, thereby angularly displaced, with the magnets of a directly adjacent transducer. The position of the north and south poles of the magnets of each transducer alternate. The metallic structure is to be moved relative to those transducers. The detection of a resonant frequency at a shifted location indicates the presence of a flaw in the metallic structure the position of which is marked by a marking device.
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