The effect of a free surface on fatigue crack behaviour

0354030 - ÚFM 2011 RIV GB eng J - Journal Article
Hutař, Pavel - Náhlík, Luboš - Knésl, Zdeněk
The effect of a free surface on fatigue crack behaviour.
International Journal of Fatigue. Roč. 32, č. 8 (2010), s. 1265-1269. ISSN 0142-1123. E-ISSN 1879-3452
R&D Projects: GA ČR GA106/09/1954; GA ČR GA101/09/0867
Institutional research plan: CEZ:AV0Z20410507
Keywords : Vertex singularity * Generalized stress intenzity factor * Stress singularity * Fatigue crack * V-notch
Subject RIV: JL - Materials Fatigue, Friction Mechanics
Impact factor: 1.799, year: 2010

The effect of a free surface on fatigue crack behaviour is discussed in the paper and generalized stress intensity factor methodology is used for a reliable estimation of the fatigue crack propagation rate in the area close to a free surface, where the effect of vertex singularity is important. It is shown that a decrease in the stress singularity exponent close to the vertex point leads to a decrease in the fatigue crack propagation rate and contributes to a typical curved crack front shape. The numerical estimations of the crack shape correspond well with experimental observations taken from the literature. The proposed methodology facilitates explanation of the experimentally observed decrease in the fatigue crack propagation rate (FCPR) for thin structures. It is shown, that decrease of FCPR depends on Poisson’s ratio and parameters of the Paris–Erdogan law for corresponding materials.
Permanent Link: http://hdl.handle.net/11104/0193122