Stress concentration factors (SCFs) in notched shaft under torsion or bending

摘要

The presence of a notch in a structural component is a common occurrence in engineering practice, and such a geometric discontinuity can easily provoke the initiation of a surface crack due to stress concentration. For this reason, strength and fatigue life of structural components should be determined by taking into account the notch effect. In this study, stress concentration factors (SCFs, K_t) of a round bar with more than one notch are considered and overlapped notch effects are examined. A simulation was presented to obtain SCFs for shaft designs with changes in section and a keyway under torsion and bending. According to the results at D/d ≥ 2 and the ratio of r/d is between 0.1 and 0.5, it was found that SCFs had not changed significantly when the distance between the keyway and shoulder fillet on the shaft under torsion or bending was 7-10 mm. SCFs for the shaft with shoulder and keyway were found between 16.5 % and 24.5 % and between 4.3 % and 12.5 % more than SCFs for the shaft with only a shoulder around the fillet area under torsion and bending, respectively.