Ultrasonic testing using a normal incident longitudinal wave is conducted for sizing a three-dimensional closed crack. The crack results from fatigue and exists vertically on the back wall of the inspected plate. The echo height of the first back-wall echo is measured at several points on the plate surface under a no-load condition. The shape and size of the crack and the stress closing the crack are determined by solving the inverse problem which compares the measured distribution of the echo height with a theoretical one. It is shown that the crack shape and size are accurately evaluated independent of the stress ratio on the crack during fatigue. It is also proven nondestructive that the stress closing the crack is higher in the shallow part of the crack than in the deep part.
|ジャーナル||Transactions of the Japan Society of Mechanical Engineers Series A|
|出版ステータス||Published - 1994|
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