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Limited weld residual stress measurements in fatigue crack propagation: Part II. FEM‐based fatigue crack propagation with complete residual stress fields
Author(s) -
SUTTON M. A.,
REYNOLDS A. P.,
GE Y. Z.,
DENG X.
Publication year - 2006
Publication title -
fatigue and fracture of engineering materials and structures
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.887
H-Index - 84
eISSN - 1460-2695
pISSN - 8756-758X
DOI - 10.1111/j.1460-2695.2006.01023.x
Subject(s) - residual stress , stress intensity factor , materials science , welding , stress field , finite element method , crack closure , structural engineering , fracture mechanics , paris' law , stress concentration , composite material , engineering
Using a limited set of residual stress measurements acquired by neutron diffraction and an equilibrium‐based, weighted least square algorithm to reconstruct the complete residual stress tensor field from the measured residual stress data, the effect of weld residual stress on fatigue crack propagation is investigated for 2024‐T351 aluminium alloy plate joined by friction stir welding. Through incorporation of the least squares, complete equilibrated residual stress field into a finite element model of the Friction Stir Weld (FSW) region, progressive crack growth along a direction perpendicular to the welding line is simulated as part of the analysis. Both the residual stress redistribution and the stress intensity factor due to the residual stress field, K res , are calculated during the crack extension process. Results show that (a) incorporation of the complete, self‐equilibrated residual stress field into a finite element (FE) model of the specimen provides a robust, hybrid approach for assessing the importance of residual stress on fatigue crack propagation, (b) the calculated stress‐intensity factor due to the residual stress field, K res , has the same trend as measured experimentally by the ‘cut‐compliance method’ and (c) the d a /d N results are readily explained with reference to the effect of the residual stress field on the applied stress intensity factor.