| 摘要 |
PROBLEM TO BE SOLVED: To simply measure the history of a stress intensity factor range without changing a measuring object and to contribute to the planning, etc. of an appropriate policy on maintenance/management as to a crack by accurately evaluating crack developability. SOLUTION: As to a crack having occurred in SUS304 steel which is metal, magnetic field distribution in its vicinity is directly measured in a non-destructive manner by means of a hall-element microscope to extract magnetic flux densities along the crack while deriving the stress intensity factor rangeΔK from the respective flux densities based on a correspondence between the flux densities and the factor rangeΔK in the SUS304 steel. Further, the history of the factor rangeΔK related to a crack is obtained by this measurement method. In cases where the history decreases from the base end of the crack to the front end thereof, the crack is evaluated as not being developable. In cases where the history increases from the base end of the crack to the front end thereof, the crack is evaluated as being developable. COPYRIGHT: (C)2007,JPO&INPIT
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