捩り疲労試験における疲労亀裂の進展に関する一考察*

概要

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An experimental result of the investigation of the fatigue crack propagation in the torsional fatigue test of S 35 C steel is described. This study aimed mainly to obtain the mode of fatigue crack propagation and relation between the propagation and the fatigue internal energy for the plainly cylindrical specimens under repeated torsion. The X-ray half value breadth and the hardness of the surface layer of the specimens were also measured as the factors in close connection with the crack growth. Results indicate : At any cycle of the test, (1) the crack length of the axial direction was 70 to 90％ of the total crack length, (2) the propagation speed was proportional to the square root of the then crack length for each direction, and (3) the fatigue internal energy was proportional to the 1/2.5th power of the then crack length. (4) The change of X-ray half value breadth as well as the hardness during the test was appreciated in relation to the stress amplitude and the internal stress of the virgin specimen
北見工業大学の論文