PROBLEM TO BE SOLVED: To provide a method of evaluating low cycle fatigue crack growth using a planar specimen which allows for measuring a strain range and applying a compressive load thereon.;SOLUTION: A method of evaluating low cycle fatigue crack growth includes steps of; applying cyclic compressive and tensile loads on a planar specimen having a clamping section on each end, a parallel section for strain measurement between the two ends, a cutout section having a pair of edges for catching a clip gauge formed on one side of the parallel section, and a precrack extending from the cutout section; determining a relationship between a crack aperture and the cyclic loads; measuring strain on the parallel section of the specimen and determining a relationship between the strain and the cyclic loads; determining an opening start point, at which a crack starts opening, in one loading cycle of the cyclic loading from the relationship between the crack aperture and the cyclic loads; determining an effective strain range corresponding to a strain variation range while the crack is open in one loading cycle using the opening start point; determining an effective strain intensity factor range using the effective strain range; and determining a fatigue crack growth rate using the effective strain intensity factor range.;COPYRIGHT: (C)2014,JPO&INPIT
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