Fatigue crack shape prediction based on the stress singularity exponent

0385372 - ÚFM 2013 RIV CH eng J - Journal Article
Hutař, Pavel - Ševčík, Martin - Náhlík, Luboš - Knésl, Zdeněk
Fatigue crack shape prediction based on the stress singularity exponent.
Key Engineering Materials. 488-489, č. 1 (2012), s. 178-181. ISSN 1013-9826.
[International Conference on Fracture and Damage Mechanics - FDM 2011 /10./. Dubrovník, 19.09.2011-21.09.2011]
R&D Projects: GA ČR GA101/09/0867
Grant - others:GA AV ČR(CZ) M100420901
Institutional research plan: CEZ:AV0Z2041904
Keywords : stress singularity exponent * crack front curvature * vertex singularity * free surface effect
Subject RIV: JL - Materials Fatigue, Friction Mechanics

In many industrial applications it is necessary to predict fatigue lifetime of the structures where the stress field near the crack front have a three-dimensional nature. Due to the existence of vertex singularity in the point where the crack front touches free surface, crack propagation in 3D structures cannot be reduced to a series of plane strain or plane stress problems along the crack front. The paper describes the influence of the vertex singularity on crack shape for threedimensional structure. The iterative process for estimation of a real crack front based on a stress singularity exponent is presented. In each node defining the crack front the stress singularity exponent has been estimated and complete crack front shape corresponding to the constant stress singularity exponent was found. The methodology presented can help to estimate crack front shape in a linear elastic fracture mechanics framework and estimate fracture parameters of fatigue cracks more accurately.
Permanent Link: http://hdl.handle.net/11104/0214640