Fatigue thresholds of holed components under in-phase and out-of-phase torsional and axial loadings

• Published in: Fatigue & fracture of engineering materials & structures Vol. 31; no. 12; pp. 1079 - 1090
• Main Authors: TANAKA, K., MORITA, K., AKINIWA, Y.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-12-2008; Blackwell; Wiley Subscription Services, Inc
• Subjects: Applied sciences; Carbon steel; combined loading of torsional and axial loading; crack closure; Crack initiation; Cycles; Exact sciences and technology; Experiments; Fatigue; Fatigue (materials); fatigue threshold; Fracture mechanics; Materials fatigue; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; non-propagating cracks; notches; Predictions; R-curve method; Rubbing; Stresses; Thresholds; Torsion; R-curve method; combined loading of torsional and axial loading; Crack closure effect; Mechanical properties; Fatigue; crack closure; non-propagating cracks; Fatigue threshold; notches
• ISSN: 8756-758X; 1460-2695
• DOI: 10.1111/j.1460-2695.2008.01298.x

ABSTRACT
The resistance‐curve (R‐curve) method was applied to the prediction of the fatigue thresholds of notched components under in‐phase and out‐of‐phase combinations of cyclic torsion and axial loadings. The prediction was compared with the experimental data obtained from thin‐walled tubular specimen of medium‐carbon steel with a hole. The stress was completely reversed and the mean stress was zero. The crack was nucleated at the position of the maximum range of the circumferential stress on the periphery of a hole, and propagated almost straight for all cases examined. The experimental data of the thresholds for crack initiation and fracture agreed well with the predictions for in‐phase and for out‐of‐phase loadings with 45° phase difference. For out‐of‐phase loading with 90°, the threshold for fracture was close to the crack initiation limit, because of the reduction of crack closure due to crack face rubbing by mode II shear cycling.