1964 年 13 巻 131 号 p. 613-618
The constant strain fatigue tests by tension-compression and by torsion were carried out in room temperature with the use of 18Cr-8Ni stainless steel and mild steel cylindrical hollow specimens, in which the relations between the effective stress range, the effective strain range and the cycles to crack were studied.
No essential influence was found on these relations resulting from the difference of the two test methods, torsion and tension-compression. Similar results were obtained as to the relations between the strain range and the cycles to crack when the maximum shear strain range was used instead of the effective strain range.
The effect of the thickness of the specimens on the cycles to crack was also studied in the torsional constant strain fatigue tests in which the cycles to crack Nf were judged from the sudden reduction of the torque range. The results show that the Nf increase with the thickness of the specimens when the outer diameters were kept constant (16mm), and that the Nf of the cylindrical solid specimen is almost doubled in comparison with that of the hollow specimen of thickness 1mm under the same strain range.