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Cohesive zone model for a transverse breathing crack in a rotor
Author(s) -
Liong Rugerri Toni,
Proppe Carsten
Publication year - 2011
Publication title -
pamm
Language(s) - English
Resource type - Journals
ISSN - 1617-7061
DOI - 10.1002/pamm.201110073
Subject(s) - cohesive zone model , structural engineering , crack closure , stiffness , crack growth resistance curve , materials science , stress intensity factor , crack tip opening displacement , mechanics , rotor (electric) , fracture mechanics , transverse plane , engineering , physics , mechanical engineering
The breathing mechanism of a transversely cracked rotor and its influence on a rotor system that appears due to the shaft weight is studied. This breathing mechanism is based on experimental and simulation result for the crack shape reported in the literature. If the crack depth is small, the crack closure line is a straight line while for larger crack depths the crack closure becomes more curved. For both cases, a method is proposed for the evaluation of the stiffness losses in the cross section that contains the crack. This method is based on a cohesive zone model (CZM) instead of linear elastic fracture mechanics (LEFM) approach, because LEFM is valid only for the fully open crack and cannot be extended to other intermediate situations. As the crack is closed, the stress intensity factor (SIF) will not appear at the boundary between the closed cracked areas and the open cracked areas. The CZM is developed for mode‐I plane strain conditions and accounts explicitly for triaxiality of the stress state by using constitutive relations. The proposed model gives more realistic results than models based on LEFM for the stiffness losses of the crack rotor system for a wide range of the crack depth. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)