This paper proposes universal J-integral range for correlating multiaxial low cycle fatigue lives. The universal J-integral range is a function of Young's modulus, yield stress, strain multiaxiality and specimen geometry, so it is not necessary to conduct multiaxial low cycle fatigue experiments to
Short crack approach for multiaxial fatigue assessment
β Scribed by M. Vormwald; O. Hertel
- Publisher
- John Wiley and Sons
- Year
- 2008
- Tongue
- English
- Weight
- 406 KB
- Volume
- 39
- Category
- Article
- ISSN
- 0933-5137
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β¦ Synopsis
Abstract
A significant part of the fatigue life is spent during short crack growth. Therefore, modelling of short fatigue crack growth offers an opportunity to improve the accuracy of numerical life assessment. Besides stating some general remarks on the short crack approach itself and on multiaxial fatigue criteria, a short crack growth based fatigue life prediction approach for multiaxial nonβproportional loading is presented. This approach accounts for the geometrical size effect by considering the geometry correction functions for semiβelliptical surface cracks in inhomogeneous gradient stress fields. The geometrical size effect is becoming significant for notch radii smaller than four times the defined technical crack size. Additionally, life influencing factors due to the statistical size effect have been taken into account. The comparison of calculated and experimentally observed fatigue lives of shouldered shafts made of S460N with notch radii of 0.2 to 4.0βmm under nonβproportional tension and torsion loading yields a satisfying accuracy.
π SIMILAR VOLUMES
A simple methodology to predict crack initiation life is described in the fatigue damage assessment of metallic structures typically used in ground vehicle industry. A phenomenological constitutive model is integrated with a notch stress-strain analysis method and local loads under general multiaxia