| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of estimating a plastic region capable of estimating the plastic region caused in stress concentration part of a member with a simple method. SOLUTION: In the method for measuring the plastic region dimension caused by plastic deformation of a measuring object that load is repeatedly added, temperature variation of the measuring object that the repeated load is added is detected with an infrared sensor. An average temperatureθ<SB>m</SB>of the temperature variation due to repeated heat generation and heat absorption is obtained, and the maximum value of the difference (θ<SB>m</SB>-θ<SB>0</SB>) between the average temperatureθ<SB>m</SB>and the initial temperatureθ<SB>0</SB>of the measuring object is obtained as a maximum temperature rise t<SB>max</SB>. When an intensity/heat conduction parameter proper for the measuring object, which gives effect to the temperature variation, is let a known number (p), the plastic region dimension (s) is obtained with the following equation: s<SP>1.7</SP>=α<SB>1</SB>×C×t<SB>max</SB>/p (where C is a constant defining the center of scattering of the plastic region dimension estimation value, andα<SB>1</SB>is a correction coefficient considering the allowable error of the plastic region dimension). The plastic region dimension means, for example, the maximum length of a crack in the propagation direction in the plastic region where the crack flaw is caused at the tip end. COPYRIGHT: (C)2006,JPO&NCIPI
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