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Nederveen, A. (author), de Jonge, J.B. (author), Tromp, P.J. (author)The effects of systematic variations in mean stress level and in spectrum and ground load severity of a flight simulation test programme have been investigated on riveted specimens (fatigue life) and sheet specimens with central saw cut (crack growth). The fatigue life and crack propagation life in Alclad 202U-T3 compared with Alclad TOT5-T6...report 1980
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de Jonge, J.B. (author), Nederveen, A. (author), Tromp, P.J. (author)Riveted specimens that are considered representative for F-27 type wing structure were subjected to comparative flight simululation test in which the gust load severity and Ground-Air-Ground cycle were systematically varied. The effect of these variations on crack propagation behaviour was studied by means of crack growth tests on 2 mm sheet...report 1978
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de Jonge, J.B. (author), Nederveen, A. (author), Tromp, P.J. (author)Fatigue tests under flight simulation loading were done on simple notched 2024-T3 Alclad sheet specimens. Reduction of the gust load amplitudes resulted in an increase of crack initiation life but hardly influenced crack propagation. Reduction of the overall stress level increased both initiation and crack propagation life. The observed...report 1978
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Schijve, J. (author), Jacobs, F.A. (author), Tromp, P.J. (author)Comparative flight-simulation tests on four types of joints of 2024- T3 sheet material were carried out with and without application of the penetrant LPS-3. Types of joints were douhle strap joint with hi-lok bolts, asymmetric strap joint, lap joint with countersunk rivets and lap joint with dimpled holes. Observations on slip during the fatigue...report 1977
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Jacobs, F.A. (author), Schijve, J. (author), Tromp, P.J. (author)Fatigue tests under flight-simulation loading have been performed on unnotched Alclad 2024-T3, anodised 2.0 mm thick sheet specimens, manufactured according to several machine-shop processes applied in the air craft industry. From the results it appears that milling is preferable to stamping. Rounding off the edges is also advantageous. The...report 1977
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Schijve, J. (author), Jacobs, F.A. (author), Tromp, P.J. (author)Flight-simulation tests based on a standardized gust load spectrum were carried out in normal air, very dry air and salt water. Specimen thicknesses were t = 2 mm and t = 10 mm, mean stress in flight was 70 or 55 MN/m². In all cases a significant effect of the environment was found. Fatigue lives for t = 10 ram were much shorter than for t = 2...report 1976
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Schijve, J. (author), Jacobs, F.A. (author), Tromp, P.J. (author)Flight-simulation tests were carried out on sheet specimens notched "by an open hole (Kt = 2.66). The material was 2024-T3 in three conditions; Alclad, bare and chemically milled. The crack initiation period and the crack propagation period were considerably shorter for the Alclad material. The significance of the cladding, both for constant...report 1976
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't Hart, W.G.J. (author), Nederveen, A. (author), Stoffels, E. (author), Tromp, J. (author)Residual strength tests have been performed on 610 mm wide centre cracked panels. During the tests, stable crack growth was filmed and crack opening displacements were measured. Fracture toughness was determined using the method of Feddersen. Flight simulation fatigue tests were carried out to investigate the crack propagation properties. A...report 1975
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Schijve, J. (author), Jacobs, F.A. (author), Tromp, P.J. (author)Tests were carried out on open-hole specimens, lugs and riveted strap joints of 2024-T3 and 7075-T6 materials. The effects of design stress level, truncating high-amplitude gust loads and omitting low-amplitude gust cycles were stuaied. Observations of the open-hole specimens include data on crack initiation, crack closure and damage increments....report 1974
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Schijve, J. (author), Jacobs, F.A. (author), Tromp, P.J. (author)Specimens of 2024-T3 and 7075-T6 were tested at 10, 1 and 0.1 cps. Values of mean stress in flight were 10.0, 8.5, 7.0, 5.5 and 4.0 kg/mm(2). The analysis of the results bears upon the frequency effect and its significance for inspection periods in service, the effect of stress level, a comparison between the two alloys, the prediction of crack...report 1973
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Schijve, J. (author), Jacobs, F.A. (author), Tromp, P.J. (author)Crack propagation was studied in 2024-T3 Alclad sheet specimens under two types of random loading and under program loading with a short period and a long period. In the program tests Lo-Hi, Lo-Hi-Lo and Hi-Lo sequences were employed. The loads were based on a gust spectrum. The crack rates were about the same under random loading and program...report 1971
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Schijve, J. (author), Jacobs, F.A. (author), Tromp, P.J. (author)Random flight-simulation tests were carried out in a similar way as in a previous investigation (NLR TH 68117) but now at lower stress levels. Truncation of the high gust loads again had a predominant effect. Increasing the truncation level considerably decreased the crack propagation rate.report 1969
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Schijve, J. (author), Jacobs, F.A. (author), Tromp, P.J. (author)A large number of flight-simulation tests were carried out on sheet specimens of 7075-T6 and 2024-T3 clad material. A gust load spectrum was adopted and a flight-by-flight loading was applied. The investigation is essentially concerned with macro-crack propagation though a few exploratory tests were conducted on the crack nucleation period. The...report 1968