Premium
Transient behaviour in the numerical analysis of plasticity induced crack closure
Author(s) -
Antunes F. V.,
Marques G. A. S.,
Chegini A. G.,
Correia L.
Publication year - 2014
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.12134
Subject(s) - plasticity , extrapolation , crack closure , closure (psychology) , materials science , mechanics , plane stress , structural engineering , residual stress , transient (computer programming) , computation , convergence (economics) , plane (geometry) , stress (linguistics) , crack tip opening displacement , finite element method , fracture mechanics , composite material , mathematics , computer science , geometry , mathematical analysis , engineering , physics , algorithm , philosophy , economic growth , linguistics , operating system , economics , market economy
ABSTRACT A transient behaviour is observed in the numerical analysis of plasticity induced crack closure at the beginning of crack propagation, as the residual plastic field is being formed. The extent of crack propagation prior to plasticity induced crack closure measurement has a major influence on the accuracy of numerical prediction and on computation time. The objective here is to quantify and understand the minimum propagation, Δ a stb , required to obtain stabilized crack opening values. For plane stress state, Δ a stb was found to increase with Δ K . Under plane strain conditions, a peak of closure exists at the beginning of crack propagation for relatively low Δ K values, which promotes relatively large transient periods. Two driving forces explain the stabilization behaviour, the formation of residual plastic wake and the stabilization of plastic strain, but the second seemed to control the phenomenon. Finally, two strategies are proposed to accelerate convergence. The first, consisting of a progressive increase of maximum load, is relevant in plane strain and 3D studies, in order to eliminate the initial peak. The second strategy consists of an extrapolation model and is very effective for plane stress conditions.