A comparative study of design code criteria for prediction of the fatigue limit under in-phase and out-of-phase tension-torsion cycles

作者：Bruun O A; Harkegard G^*

来源：International Journal of Fatigue, 2015, 73: 1-16.

DOI：10.1016/j.ijfatigue.2014.10.015

• Design code
• Fatigue limit
• Out-of-phase
• Plane stress

Criteria for the fatigue assessment of multiaxial, non-proportional stress cycles have been prescribed by engineering design codes and implemented in fatigue post-processors. Cases in point are the normalstress (API RP 17G), Findley, Mises (BPVC-VIII-2), Mises-Sines, Tresca (BPVC-III-1), and Tresca-Sines (BPVC-VIII-3) criteria (design codes). In the present work, these criteria have been applied to the tension-torsion fatigue limit.
Theoretical predictions have been compared with fatigue test data from 220 different tension-torsion fatigue test series on wrought steel, cast iron and an Al alloy. The normal-stress criterion yields excellent predictions for cast iron, whereas those for wrought alloys tend to be unsafe. For wrought steel and the Al alloy, the shear-stress criteria yield predictions that are closer to the observed data. For all criteria, mean values of the predictions are within 12% of the observed fatigue limits, whereas standard deviations are typically <20% of the mean values.
In addition to the traditional formulation of critical-plane criteria, based on extreme values of normal and shear stress components during a cycle, a 'simultaneous stress component' (SSC) formulation according to the ASME code, based on the stress components for a critical pair of points in time during the cycle, has been considered. For the stress cycles investigated, the SSC formulation makes a significant difference only for the Findley criterion.

• 出版日期2015-4