A study on fatigue crack growth behavior subjected to a single tensile overload

Neutron diffraction and electric potential experiments were carried out to investigate the growth behavior of a fatigue crack subjected to a single tensile overload. The specific objectives were to (i) probe the crack tip deformation and fracture behaviors under applied loads; (ii) examine the overl...

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Bibliographic Details
Published in:Acta materialia 2011, Vol.59 (2), p.485-494
Main Authors: Lee, S.Y., Liaw, P.K., Choo, H., Rogge, R.B.
Format: Article
Language:English
Subjects:
Compressive properties
Crack closure
Crack propagation
Driving
Electric potential
Expansion
Fatigue crack growth
Fatigue failure
Fracture mechanics
Neutron diffraction
Overload
Residual stress
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Summary:Neutron diffraction and electric potential experiments were carried out to investigate the growth behavior of a fatigue crack subjected to a single tensile overload. The specific objectives were to (i) probe the crack tip deformation and fracture behaviors under applied loads; (ii) examine the overload-induced transient crack growth micromechanism; (iii) validate the effective stress intensity factor range based on the crack closure approach as the fatigue crack tip driving force; and (iv) establish a quantitative relationship between the crack tip driving force and crack growth behavior. Immediately after a single tensile overload was introduced and then unloaded, the crack tip became blunt and enlarged compressive residual stresses in both magnitude and zone size were observed around the crack tip. The results show that the combined contributions of the overload-induced enlarged compressive residual stresses and crack tip blunting with secondary cracks are responsible for the observed changes in the crack opening load and the resultant post-overload transient crack growth behavior.
ISSN:1359-6454
1873-2453
DOI:10.1016/j.actamat.2010.09.049