𝔖 Bobbio Scriptorium
✦   LIBER   ✦

A multiaxial fatigue failure criterion considering the effects of the defects

✍ Scribed by E. Thieulot-Laure; S. Pommier; S. Fréchinet


Publisher
Elsevier Science
Year
2007
Tongue
English
Weight
702 KB
Volume
29
Category
Article
ISSN
0142-1123

No coin nor oath required. For personal study only.

✦ Synopsis


An endurance criterion is proposed which aims at capitalizing the advantages of both fracture mechanics and of energetic or stressbased approaches. As a matter of fact, fracture mechanics based approaches allow building probabilistic criterions by introducing the statistic distributions of defects sizes, positions and orientations. On the other hand, stress-based approaches allow building multiaxial failure and life criterions. However, as shown by the diagram of Kitagawa and Takahashi [Kitagawa H, Takahashi S. Applicability of fracture mechanics to very small cracks. In: ASM Proceedings of 2nd International Conference on Mechanical Behaviour of Materials, Metalspark, Ohio. 1976, pp. 627-631], none of these approaches applies over the whole range of possible defects dimensions. For large defects, fracture mechanics concepts apply and the fatigue limit is deduced from the threshold stress intensity factor and the defect size. There is usually a threshold below which the sensitivity of the fatigue limit to the defect size becomes negligible. In that domain, Linear Elastic Fracture Mechanics (LEFM) overestimates the fatigue limit and stress-based approaches are more pertinent. In the present paper, the LEFM framework is used, defects are assumed to be cracks. The size effect exhibited by Kitagawa and Takahashi [Kitagawa H, Takahashi S. Applicability of fracture mechanics to very small cracks. In: ASM Proceedings of 2nd International Conference on Mechanical Behaviour of Materials, Metalspark, Ohio. 1976, pp. 627-631] is accounted for through the T-stress parameter, which is the first non singular term in the asymptotic development of the stresses at crack tip. The proposed criterion is a non-propagation criterion based on a critical distortional elastic energy in the crack tip region. The use of an energetic criterion ensures the consistency with endurance criterion. The specificity of our approach lies in the calculation of the distortional energy using the displacement fields of LEFM which ensures the consistency with fracture mechanics.


📜 SIMILAR VOLUMES


The fatigue failure criterion of the mix
✍ Mao-Hua Wang 📂 Article 📅 1984 🏛 Elsevier Science 🌐 English ⚖ 443 KB

## Ahstrae-A new fatigue failure criterion is proposed in the view of the modern fracture theory in this paper. Under the fatigue loading of the fully mixed model for the body including the pnetrable cracks. A general expression in quadrate approximation is established, which includes the importan

Comparison between defects and micro-not
✍ F. Morel; A. Morel; Y. Nadot 📂 Article 📅 2009 🏛 Elsevier Science 🌐 English ⚖ 591 KB

This paper attempts to improve the understanding of the multiaxial high cycle fatigue response of micro sized stress concentrations or notches of different geometries. The investigation is composed of an experimental part and a numerical part. In the former, three types of micro-notches or ''artific

Influence of mean stress on the multiaxi
✍ H. Gadouini; Y. Nadot; C. Rebours 📂 Article 📅 2008 🏛 Elsevier Science 🌐 English ⚖ 346 KB

Artificial spherical defects (400 lm) are introduced at the surface of C35 steel fatigue samples. Fatigue tests are conducted under tension and torsion with different mean stress levels in order to determine the fatigue limit. Experimental results show that the effect of mean stress under both torsi