Effect of Overload Cycle [S] on Subsequent Fatigue Crack Propagation in 2024-T3 Aluminum Alloy PDF Download

Author: Eric F. J. Von Euw
Publisher:
ISBN:
Category : Aluminum alloys
Languages : en
Pages : 86

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Author: Eric F. J. Von Euw
Publisher:
ISBN:
Category : Aluminum alloys
Languages : en
Pages : 172

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Author: V. W. Trebules
Publisher:
ISBN:
Category : Crack propagation
Languages : en
Pages : 32

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Book Description
The effect of multiple overloads on subsequent fatigue crack propagation in 2024-T3 aluminum alloy specimens was studied, and 1, 2, 10, 100, 1000, and 5000 overload cycle tests were run. Typical tests consisted of running constant ?K tests where ?K=15ksiin.(16.5MN/m3/2) and ?=1.05(?=Kmax/?K). The maximum overload level was 50 percent ?K or Kmax=22.5ksiin.(24.7MN/m3/2). The usefulness of closure concepts in aiding the understanding of fatigue crack propagation due to overloads is considered. Evidence is given to demonstrate the general applicability of closure concepts for analysis of fatigue crack propagation results.

Author: National Aeronautics and Space Adm Nasa
Publisher: Independently Published
ISBN: 9781792718212
Category :
Languages : en
Pages : 28

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Fatigue crack growth tests were conducted on 0.09 inch thick, 3.0 inch wide middle-crack tension specimens cut from sheets of 2024-T3 aluminum alloy. The tests were conducted using a load sequence that consisted of a single block of 2,500 cycles of constant amplitude loading followed by an overload/underload combination. The largest fatigue crack growth life occurred for the tests with the overload stress equal to 2 times the constant amplitude stress and the underload stress equal to the constant amplitude minimum stress. For the tests with compressive underloads, the fatigue crack growth life decreased with increasing compressive underload stress. Dawicke, David S. Langley Research Center NASA-CR-201668, NAS 1.26:201668 NAS1-96014; RTOP 538-02-10-01...

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 14

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Author: B. M. Hillberry
Publisher:
ISBN:
Category : Metals
Languages : en
Pages : 0

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The fatigue crack delay behavior due to single overload/underload sequences was studied in center crack panel specimens of 2024-T3 aluminum alloy. The applied loading consisted of constant amplitude loading, an applied overload immediately followed by an underload and then constant amplitude loading at the pre-overload level. The loading parameters investigated are the stress intensity ratios, overload level to maximum fatigue level, underload level to overload level, and minimum fatigue level to overload level. The results show that increasing the amount of underload decreases the number of delay cycles. Also, it is shown that the number of delay cycles is directly related to the minimum growth rate following the overload. The concept of crack closure is extended to include the effects of the overload/underload sequence. From this the maximum value of the opening stress intensity level and the minimum growth rate are determined. This is used to predict the number of delay cycles.

Author: Victor W. Trebules (Jr)
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Author: Ralph Ivan Stephens
Publisher: ASTM International
ISBN:
Category : Alloys
Languages : en
Pages : 345

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Author: WX. Alzos
Publisher:
ISBN:
Category : Crack propagation
Languages : en
Pages : 20

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Tests, represented in a three-dimensional matrix, were performed to investigate the effects of a single overload/underload sequence on the fatigue crack-growth rate in 2024-T3 aluminum alloy. Three different stress intensity ratios were studied to investigate the delay phenomenon: (1) overload level to maximum cyclic level, Kol/Kmax; (2) underload level to overload level, Kul/Kol; and (3) minimum cyclic level to overload level, Kmin/Kol. These ratios ranged from 1.6 to 3.0, -1.0 to +0.3, and 0.11 to 0.3, respectively. All tests had the same overload stress intensity level. Sufficient data were recorded to accurately determine the crack-growth rate through the overload affected zone. The crack length versus number of cycles data for each test were represented by a spline function which was then analytically differentiated to obtain the growth rate. The number of delay cycles was found to be directly related to the minimum growth rate following the overload/underload sequence. The ratios Kol/Kmax and Kul/Kol were shown to be of particular significance to the delay while the ratio Kmin/Kol was shown to be of less significance. The results were correlated with an extended crack closure concept. From this the maximum value of the opening stress intensity level following the overload/underload sequence can be determined and used to predict the number of delay cycles.

Author: National Symposium Fracture Mechanics Staff
Publisher: ASTM International
ISBN: 9780803103627
Category : Science
Languages : en
Pages : 324

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