| 摘要 |
PURPOSE:To permit obtaining of data having no disturbance and to improve analysis accuracy by subjecting only the crack generating part of a test piece existing already in a tensile stress field to quick cooling down to the temp. below the rupture toughness of said test piece so that brittle fracture is generated. CONSTITUTION:Prescribed load P is first acted to the test piece 1 from both sides thereof to apply the tensile stress to the test piece 1. Notch end temp. T2 of the crack generating part 5 is monitored by a temp. sensor 10 at this time and the test piece is kept preserved at the temp. at which the brittle fracture is not generated. A temp. controller 8 is thereafter actuated and a valve 7 is opened to supply a refrigerant in a storage tank 4 to a cooling tank 9 to quickly cool the crack generating part 5 of the test piece 1, by which the test piece is cooled down to the temp. T3 below the brittle fracture generating temp. of the material and to generate cracks in the crack generating part 5. The data having no disturbance is thus obtd., by which the analysis accuracy is improved.
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