Premium
Numerical determination of plastic CTOD
Author(s) -
Antunes F.V.,
Díaz F.A.,
VascoOlmo J.M.,
Prates P.
Publication year - 2018
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/ffe.12869
Subject(s) - crack tip opening displacement , crack growth resistance curve , crack closure , materials science , fracture mechanics , structural engineering , displacement (psychology) , finite element method , composite material , polygon mesh , mechanics , geometry , mathematics , engineering , physics , psychology , psychotherapist
In previous works, a da/dN versus plastic crack tip opening displacement model was proposed to study fatigue crack growth. The plastic crack tip opening displacement, δ p , which quantifies the crack tip plastic deformation, is determined numerically using the finite element method. The predictions are affected by different numerical parameters which must be identified and studied. The main parameters are the crack propagation distance, the distance of measurement points relatively to the crack tip, the size of crack tip elements, and the number of load cycles between crack increments. Some crack propagation is required for the stabilization of δ p, which occurs when δ p reaches its minimum value. The measurement point behind crack tip has a major effect on δ p . The peak value occurs at the first node behind crack tip and a progressive decrease of sensitivity is observed with the increase of distance to crack tip. A mesh refinement study showed a coincidence of the predictions obtained with different meshes, which is a good indication for the robustness of the procedure. Finally, there is a significant effect of the number of load cycles between crack increments, NLC, in the presence of crack closure. The increase of NLC reduces the crack opening level and so increases δ p .