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Phase field modelling of stress corrosion

Ståhle, Per LU and Hansen, Eskil LU (2015) In Engineering Failure Analysis 47. p.241-251
Abstract
The evolution of surfaces exposed to an aggressive environment and mechanical load is studied. This is a process of stress corrosion that leads to pitting, crack initiation and growing cracks. In conventional fracture analyses a known or a postulated crack is required. A serious complication is that a large part of the lifetime of a crack or a surface flaw is spent during the initiation of the crack. The knowledge of the mechanisms leading from a pit, flaw, scratch, etc. to a crack is very limited. The motivation for the present study is to provide a model that will increase the understanding of the transition from stress induced surface roughening and pitting to growing cracks. The evolution of the originally flat surface involves free... (More)
The evolution of surfaces exposed to an aggressive environment and mechanical load is studied. This is a process of stress corrosion that leads to pitting, crack initiation and growing cracks. In conventional fracture analyses a known or a postulated crack is required. A serious complication is that a large part of the lifetime of a crack or a surface flaw is spent during the initiation of the crack. The knowledge of the mechanisms leading from a pit, flaw, scratch, etc. to a crack is very limited. The motivation for the present study is to provide a model that will increase the understanding of the transition from stress induced surface roughening and pitting to growing cracks. The evolution of the originally flat surface involves free strain energy, chemical energy and gradient energy. A phase field model is used to capture the driving forces that the free energy causes. The flat surface is unstable and develop a waviness. Initially while the waves are shallow a spectrum of favoured spatial frequencies are found to be in accordance with the Asaro-Tiller-Grinfeld theory. Later the surface curvature becomes larger at the depressions than at the higher parts of the surface. This increases the growth rate of formed pits. The pits finally develop into cracks. Also massive branching of pits and cracks is observed. (C) 2014 Elsevier Ltd. All rights reserved. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Stress corrosion, Crack initiation, Surface morphology, Phase field, model, Anti-plane strain
in
Engineering Failure Analysis
volume
47
pages
241 - 251
publisher
Elsevier
external identifiers
  • wos:000347757600002
  • scopus:84911869294
ISSN
1350-6307
DOI
10.1016/j.engfailanal.2014.07.025
language
English
LU publication?
yes
id
811b5d06-9d5d-4b89-acc4-7ae7bb8f7c23 (old id 5069986)
date added to LUP
2015-02-25 15:03:53
date last changed
2017-09-10 03:04:03
@article{811b5d06-9d5d-4b89-acc4-7ae7bb8f7c23,
  abstract     = {The evolution of surfaces exposed to an aggressive environment and mechanical load is studied. This is a process of stress corrosion that leads to pitting, crack initiation and growing cracks. In conventional fracture analyses a known or a postulated crack is required. A serious complication is that a large part of the lifetime of a crack or a surface flaw is spent during the initiation of the crack. The knowledge of the mechanisms leading from a pit, flaw, scratch, etc. to a crack is very limited. The motivation for the present study is to provide a model that will increase the understanding of the transition from stress induced surface roughening and pitting to growing cracks. The evolution of the originally flat surface involves free strain energy, chemical energy and gradient energy. A phase field model is used to capture the driving forces that the free energy causes. The flat surface is unstable and develop a waviness. Initially while the waves are shallow a spectrum of favoured spatial frequencies are found to be in accordance with the Asaro-Tiller-Grinfeld theory. Later the surface curvature becomes larger at the depressions than at the higher parts of the surface. This increases the growth rate of formed pits. The pits finally develop into cracks. Also massive branching of pits and cracks is observed. (C) 2014 Elsevier Ltd. All rights reserved.},
  author       = {Ståhle, Per and Hansen, Eskil},
  issn         = {1350-6307},
  keyword      = {Stress corrosion,Crack initiation,Surface morphology,Phase field,model,Anti-plane strain},
  language     = {eng},
  pages        = {241--251},
  publisher    = {Elsevier},
  series       = {Engineering Failure Analysis},
  title        = {Phase field modelling of stress corrosion},
  url          = {http://dx.doi.org/10.1016/j.engfailanal.2014.07.025},
  volume       = {47},
  year         = {2015},
}