This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
The non-coplanar coalescence of interacting defects in fatigue
Technical Paper
2001-01-4052
ISSN: 0148-7191, e-ISSN: 2688-3627
Annotation ability available
Sector:
Language:
English
Abstract
Defects in real structures frequently have complex shapes. The present work examines complex defects which result from the interaction of adjacent coplanar semi-elliptical cracks. Attention is focused on fatigue growth leading to coalescence and the formation of a coplanar single defect with a re-entrant sector.
An experimental study investigated the fatigue crack path on the free surface. The study found that the deviations from the straight crack path determine the size of the re-entrant sector and whether coalescence occurs on the surface or sub-surface. Surface coalescence occurs by a shear mechanism resulting in a step in the coalesced crack front.
A numerical line spring analysis based on the concept introduced by Rice and Levy [1] and extended by Parks and White [2] to include Mode II and III component, has been used to investigate the effect of coalescence in re-entrant sector on the crack tip parameters. The presence of a step in the re-entrant sector introduces a Mode III component and reduces amplified values of Mode I stress intensity factor, which is a feature of coplanar coalescence. The study concludes with discussion of the significance of non-coplanar coalescence on catastrophic brittle failure.
Authors
Citation
Bezensek, B. and Hancock, J., "The non-coplanar coalescence of interacting defects in fatigue," SAE Technical Paper 2001-01-4052, 2001, https://doi.org/10.4271/2001-01-4052.Also In
References
- Rice, J.R. Levy, N. 1972 The part-through surface crack in an elastic plate Journal of Applied Mechanics 39 1 185 194
- Parks, D.M. White, C.S. Elastic-plastic line-spring finite elements for surface cracked plates and shells Journal of Pressure Vessels Technology 104 1982 287 292
- Twaddle, B.R. Hancock, J.W. 1986 The Development of Cracks by Defect Coalescence Fatigue of Offshore Structures EMAS
- Soboyejo, W.O. Knott, J.F. Walsh, M.J. Cropper, K.R. Fatigue crack propagation of coplanar semi-elliptical cracks in pure bending Engineering Fracture Mechanics 37 2 1990 323 340
- Leek, T.H. Howard, I.C. An examination of methods of assessing interacting surface cracks by comparison with experimental data International Journal of Pressure Vessels and Piping 68 1996 181 201
- Bezensek, B. Hancock, J.W. Brittle fracture from interacting surface breaking defects Proceedings of ASME PVP2001 conference Atlanta, Ga. 2001
- Bezensek, B. Hancock, J.W. Ductile tearing from interacting surface breaking defects Proceedings of 10 ICF conference Honolulu, Hi. 2001
- Bezensek, B. Hancock, J.W. Failure of complex defects with re-entrant sectors by fatigue, ductile and brittle mechanisms 2001
- Scott, P.M. Thorpe, T.W. Atomic Energy Research Establishment Harwell, UK 1981
- ABAQUS/Standard Theory Manual Hibbitt, Karlsson and Sorensen, inc Providence, Rhoad Island 1998
- Betegón, C. Hancock, J.W. Two-parameter characterisation of elastic-plastic crack-tip fields Journal of Applied Mechanics 58 1991 104 110
- Williams, M.L. 1957 On the stress distribution at the base of a stationary crack ASME Journal of Applied Mechanics 24 111 114
- Wang, Y.Y. Parks, D.M. 1992 Evaluation of the elastic T-stress in surface plates using the line-spring method International Journal of Fracture 56 25 40
- Cottrell, B. Rice, J.R. Slightly curved or kinked cracks International Journal of Fracture 16 2 1980 155 169
- Melin, S. Why do cracks avoid each other? International Journal of Fracture 23 1983 37 45