The evolution of crack-tip stresses during a fatigue overload event
(2010) In Acta Materialia 58(11). p.4039-4052- Abstract
- The mechanisms responsible for the transient retardation or acceleration of fatigue crack growth subsequent to overloading are a matter of intense debate. Plasticity-induced closure and residual stresses have often been invoked to explain these phenomena, but closure mechanisms are disputed, especially under conditions approximating to generalised plane strain. In this paper we exploit synchrotron radiation to report very high spatial resolution two-dimensional elastic strain and stress maps at maximum and minimum loading measured under plane strain during a normal fatigue cycle, as well as during and after a 100% overload event, in ultra-fine grained AA5091 aluminium alloy. These observations provide direct evidence of the material stress... (More)
- The mechanisms responsible for the transient retardation or acceleration of fatigue crack growth subsequent to overloading are a matter of intense debate. Plasticity-induced closure and residual stresses have often been invoked to explain these phenomena, but closure mechanisms are disputed, especially under conditions approximating to generalised plane strain. In this paper we exploit synchrotron radiation to report very high spatial resolution two-dimensional elastic strain and stress maps at maximum and minimum loading measured under plane strain during a normal fatigue cycle, as well as during and after a 100% overload event, in ultra-fine grained AA5091 aluminium alloy. These observations provide direct evidence of the material stress state in the vicinity of the crack-tip in thick samples. Significant compressive residual stresses were found both in front of and behind the crack-tip immediately following the overload event. The effective stress intensity at the crack-tip was determined directly from the local stress field measured deep within the bulk (plane strain) by comparison with linear elastic fracture mechanical theory. This agrees well with that nominally applied at maximum load and 100% overload. After overload, however, the stress fields were not well described by classical K fields due to closure-related residual stresses. Little evidence of overload closure was observed sometime after the overload event, in our case possibly because the overload plastic zone was very small. Crown Copyright (C) 2010 Published by Elsevier Ltd. on behalf of Acta Materialia Inc. All rights reserved. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/1631602
- author
- Steuwer, Axel LU ; Rahman, M. ; Shterenlikht, A. ; Fitzpatrick, M. E. ; Edwards, L. and Withers, P. J.
- organization
- publishing date
- 2010
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- field, crack-tip stress, Plasticity-induced closure, Stress intensity factor, Overload, Retardation
- in
- Acta Materialia
- volume
- 58
- issue
- 11
- pages
- 4039 - 4052
- publisher
- Elsevier
- external identifiers
-
- wos:000278562800023
- scopus:78449263067
- ISSN
- 1873-2453
- DOI
- 10.1016/j.actamat.2010.03.013
- language
- English
- LU publication?
- yes
- id
- f8f13201-64ca-4965-8462-68040a3a9e2e (old id 1631602)
- date added to LUP
- 2016-04-01 09:59:38
- date last changed
- 2022-04-27 17:34:37
@article{f8f13201-64ca-4965-8462-68040a3a9e2e,
abstract = {{The mechanisms responsible for the transient retardation or acceleration of fatigue crack growth subsequent to overloading are a matter of intense debate. Plasticity-induced closure and residual stresses have often been invoked to explain these phenomena, but closure mechanisms are disputed, especially under conditions approximating to generalised plane strain. In this paper we exploit synchrotron radiation to report very high spatial resolution two-dimensional elastic strain and stress maps at maximum and minimum loading measured under plane strain during a normal fatigue cycle, as well as during and after a 100% overload event, in ultra-fine grained AA5091 aluminium alloy. These observations provide direct evidence of the material stress state in the vicinity of the crack-tip in thick samples. Significant compressive residual stresses were found both in front of and behind the crack-tip immediately following the overload event. The effective stress intensity at the crack-tip was determined directly from the local stress field measured deep within the bulk (plane strain) by comparison with linear elastic fracture mechanical theory. This agrees well with that nominally applied at maximum load and 100% overload. After overload, however, the stress fields were not well described by classical K fields due to closure-related residual stresses. Little evidence of overload closure was observed sometime after the overload event, in our case possibly because the overload plastic zone was very small. Crown Copyright (C) 2010 Published by Elsevier Ltd. on behalf of Acta Materialia Inc. All rights reserved.}},
author = {{Steuwer, Axel and Rahman, M. and Shterenlikht, A. and Fitzpatrick, M. E. and Edwards, L. and Withers, P. J.}},
issn = {{1873-2453}},
keywords = {{field; crack-tip stress; Plasticity-induced closure; Stress intensity factor; Overload; Retardation}},
language = {{eng}},
number = {{11}},
pages = {{4039--4052}},
publisher = {{Elsevier}},
series = {{Acta Materialia}},
title = {{The evolution of crack-tip stresses during a fatigue overload event}},
url = {{http://dx.doi.org/10.1016/j.actamat.2010.03.013}},
doi = {{10.1016/j.actamat.2010.03.013}},
volume = {{58}},
year = {{2010}},
}