The equivalent stress on the critical plane determined by the maximum covariance of normal and shear stresses

Mat.-wiss. u. Werkstofftech

Walat

et al. 2014

This paper presents an analysis of the multiaxial fatigue properties of two selected aluminium alloys. Several experimental results were used to perform the analysis e.g. the latest experimental results done in Opole University of Technology on PA6 (2017 A), PA4 (6068) under bending, torsion, and combined bending with torsion. Analyses of the results were done to find similarities of the multiaxial fatigue behaviour of selected aluminium alloys. Based on the (σa – τa) curves, prepared for a fixed number of cycles, it was possible to show some tendencies of the multiaxial fatigue behaviour of selected material group. This is an important indicator while selecting proper multiaxial fatigue failure criterion suitable to perform fatigue life assessment of aluminium alloys.

{normalσ}_{eq} (t) = \frac{{normalσ}_{af}}{{normalτ}_{af}} \max_{normalt} {{normalτ}_{ηs} (t)} + (2 - \frac{{normalσ}_{af}}{{normalτ}_{af}}) {normalσ}_{normalη} (t)

…”

Section: Comparison Of the Selected Multiaxial Fatigue Failure Criteriamentioning

confidence: 99%

Multiaxial fatigue behaviour of AA6068 and AA2017A aluminium alloys under in-phase bending with torsion loading condition

Niesłony

Mat.-wiss. u. Werkstofftech

Walat

et al. 2014

“…The next important step in fatigue life determination is determination of the critical plane orientation angle corresponding to the maximum effort of the material. In the paper, the critical plane position was determined with the method of damage accumulation, and the expression for normal and shear stresses was completed with the well known correction function using fatigue limits for bending and torsion [9,10]:…”

Section: The Algorithm Of Fatigue Life Assessmentmentioning

confidence: 99%

Fatigue Life Estimation under Cyclic Loading Including Out-of-Parallelism of the Characteristics

Kurek

2011

AMM

The paper presents an algorithm of fatigue life determination for materials with no parallel fatigue characteristics under pure bending and pure torsion. The presented model uses the iteration method, and the applied fatigue criterion is function of the ratio of normal and shear stresses coming from bending and torsion, respectively. Three materials were applied for analysis: CuZn40Pb2 brass, 30CrNiMo8 medium-alloy steel and 35NCD16 high-alloy steel.

Comparison of the fatigue characteristics for some selected structural materials under bending and torsion

Kurek

2011

Mater Sci

The paper presents a review of the multiaxial fatigue criteria including a ratio of normal and shear stresses. The paper also contains fatigue characteristics for bending and torsion of some selected constructional materials. The ratio of normal stresses to shear stresses was determined for the defined number of cycles N f in the range 5⋅10 4 ÷2⋅10 6 . Moreover, from the performed analysis of fatigue equations and the relative difference R it appears that materials can be divided into groups for which it is possible or it is not possible to apply the constant value of the considered ratio in the criteria including this ratio.