| Novel Robust Models for Damage Tolerant Helicopter Components |
DEC 2002 |
65 pages |
| Authors:
M. Lang; P. E. Irving; C. Stolz; V. Zitounis; CRANFIELD UNIV (UNITED KINGDOM)
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 | A new approach to the prediction of crack growth fatigue lives under variable amplitude loading, the K(PR) approach, is described. K(PR) is the minimum stress intensity for crack propagation during a loading cycle and is sensitive to the immediate loading history at the crack tip. Four parameters describe changes in K(PR) as a function of load history. Unlike other models the KPR model has no fitting parameter. The four KPR ... |
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| Factors Influencing Propagation of Mode III Fatigue Cracks under Torsional Loading |
82 |
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| Authors:
N. J. Hurd; P. E. Irving; GKN TECHNOLOGY LTD WOLVERHAMPTON (ENGLAND)*
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 | Mode III fatigue crack growth rates have been measured in circumferentially notched specimens of a quenched and tempered steel in a range of strength levels. It is found that crack growth rates are slower by a factor of between 10 and 50 times compared with Mode I data obtained in compact tension specimens. The relative stability of Mode III and Mode I are influenced by the mean stress and by ... |
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| PURITY AND FRACTURE TOUGHNESS BEHAVIOUR IN STEELS |
76 |
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| Authors:
P. E. Irving; M. P. Seah; A. Kurzfeld; NATIONAL PHYSICAL LAB TEDDINGTON (ENGLAND)
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| K(Sub IC) tests were performed in accordance with ASTM E399 recommendations at three levels of purity. These were a standard commercial En24 steel, a vacuum induction melted 4340 steel, and a high purity En24 steel. The steels were austenitized at 840 C, oil quenched and tempered for 1 hour at 200 C, 400 C or 550 C and water quenched. The 3-point bend K(Sub IC) results are plotted against 0.2% ... |
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| A STUDY OF THE EFFECTS OF MECHANICAL AND ENVIRONMENTAL VARIABLES ON FATIGUE CRACK CLOSURE |
DEC 75 |
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| Authors:
P. E. Irving; J. L. Robinson; C. J. Beevers
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| a study of the effects of mechanical and environmental variables on fatigue crack closure |
75 |
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| Authors:
P. E. Irving; J. L. Robinson; C. J. Beevers
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| using the potential drop technique, fatigue crack closure has been monitored in pin loaded sen specimens of alpha-titanium, a titanium alloy and en24 steel. the specimens were tested in tension-tension under conditions closely approximating to plane strain, and closure was only detected in vacua of better than 133 mnm to the minus 2(0.0010 torr). no significant closure was detected in air. the extent of the crack area closed at minimum ... |
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| THE EFFECT OF AIR AND VACUUM ENVIRONMENTS ON FATIGUE CRACK GROWTH RATES IN TI-6AL-4V |
FEB 74 |
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| Authors:
P. E. Irving; C. J. Beevers
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| FATIGUE CRACK GROWTH BEHAVIOUR OF Ti-6Al-4V IN AIR AND VACUUM AT ROOM AND ELEVATED TEMPERATURES |
74 |
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| Authors:
C. J. Beevers; P. E. Irving; BIRMINGHAM UNIV (ENGLAND)
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| Fatigue-crack growth tests have been performed on a Ti-6Al-4V alloy with an alpha - 14%Beta phase microstructure. Detailed examinations of fatigue- crack growth curves indicated the existence of two modes of fatigue-crack growth, (a) microstructure-insensitive and (b) microstructure-sensitive and environment-sensitive. The transition from (a) to (b) occurs when the reverse plasticity at the crack tip is of a similar magnitude to the alpha grain size. The effect of air environment ... |
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| THE SLOW FATIGUE CRACK GROWTH AND THRESHOLD BEHAVIOUR OF A MEDIUM CARBON ALLOY STEEL IN AIR AND VACUUM |
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| Authors:
R. J. Cooke; P. E. Irving; G. S. Booth; C. J. Beevers
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