Imperial College London
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ProfessorDavidNowell

Faculty of Engineering, Department of Mechanical Engineering

Chair in Machine Dynamics and Director of the VUTC
 
 
 
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Contact

 

+44 (0)20 7594 1458d.nowell Website

 
 
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Location

 

561City and Guilds BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Nowell:2013:10.1111/j.1460-2695.2012.01707.x,
author = {Nowell, D and Kartal, ME and De, Matos PFP},
doi = {10.1111/j.1460-2695.2012.01707.x},
journal = {FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES},
pages = {3--13},
title = {Digital image correlation measurement of near-tip fatigue crack displacement fields: constant amplitude loading and load history effects},
url = {http://dx.doi.org/10.1111/j.1460-2695.2012.01707.x},
volume = {36},
year = {2013}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Recent work by de Matos and colleagues employed digital image correlation to measure near tip displacement fields for fatigue cracks in 6082 T6 aluminium alloy. The main focus of this work was to directly measure fatigue crack closure, but the measurements can also be used to examine conditions at and ahead of the crack tip. In this paper, the results are re-analysed and compared to two crack-tip deformation models. The first assumes simple elastic deformation (according the Westergaard solution). This allows the history of crack-tip stress intensity to be examined. Reasonable agreement with the elastic model is obtained, although there is a residual stress intensity caused by the plastic wake, which gives rise to crack closure. The second model examined is a simple elasticplastic assumption, proposed by Pommier and colleagues. This can be applied to constant amplitude loading, although the results obtained here are very similar to the elastic case. A slightly more complex load case (a single overload in an otherwise constant amplitude variation of load) gives a much more complicated crack-tip history. Here, the importance of crack-tip plastic displacement, represented by the second term in Pommier’s model becomes much clearer. Load history effects are captured by the residual value of this term and its associated displacement fields as well as by stress intensity factor. The implications for further modelling and experimental work are discussed.
AU  - Nowell,D
AU  - Kartal,ME
AU  - De,Matos PFP
DO  - 10.1111/j.1460-2695.2012.01707.x
EP  - 13
PY  - 2013///
SN  - 8756-758X
SP  - 3
TI  - Digital image correlation measurement of near-tip fatigue crack displacement fields: constant amplitude loading and load history effects
T2  - FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES
UR  - http://dx.doi.org/10.1111/j.1460-2695.2012.01707.x
VL  - 36
ER  -
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