| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a nondestructive inspecting method capable of more easily measuring a stress intensity factor at a stress concentration part at higher precision without detecting cracks at the stress concentration part of a member to evaluate the degree of fatigue at the stress concentration part even if the crack has actually not occurred at the stress concentration part. Ž<P>SOLUTION: At first the density distribution of magnetic fluxes at the surface of the stress concentration part of a sample is measured. Then, it is detected that the propagation of cracks from the stress concentration part is shown as a curved line protruding toward downward of the magnetic flux density distribution along the estimated direction. When the magnetic flux density distribution shows the curved shape, the distance from the stress concentration part to the top of the curved shape is measured. Based on the linear relationship between the distance and the stress intensity factor at the stress concentration part, the stress intensity factor is determined from the distance. When the magnetic flux density distribution does not show the curved shape, it is determined that the fatigue does not generate at the stress concentration part yet. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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