Gradient dependent multiaxial high-cycle fatigue criterion
For a uniaxial normal stress load, it is well known that the presence of a stress gradient has a net beneficial effect on the corresponding endurance limit. The paper presents the formulation of a multiaxial fatigue criterion that takes into account the stress gradient effect. The work starts with a careful analysis of experimental results of uniaxial cyclic normal stresses and of cyclic shear stresses. This examination shows that the fatigue endurance is mainly affected by the gradient of normal stresses. Variations of the gradient of shear stress in torsion tests do not alter significantly the corresponding endurance limit. Based on these conclusions a gradient dependent fatigue criterion of the critical plane type is formulated. The proposed formula is applied in fully reversed in-phase bending and torsion loading. It is demonstrated theoretically that the proposed gradient dependent criterion leads to the ellipse arc formula of Gough and Pollard. A noticeable result is that within the proposed framework the discrepancies apparently existing between experimental results with gradient-free stress conditions and of results incorporating non-zero stress gradients are eliminated.
Bibliographic Reference: Article: Biaxial/Multiaxial Fatigue
Record Number: 199511143 / Last updated on: 1995-08-23
Original language: en
Available languages: en