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Wanhill, R.J.H. (author), Schra, L. (author), 't Hart, W.G.J. (author)This report compares the mechanical properties, fracture toughness and fatigue crack growth properties of the damage tolerant/medium strength aluminium plate alloys 2024-T351, 2324-T39, 8090-T651 and 8090-T8171. The main objective, in view of previous work, was to determine whether damage tolerant 8090-T8171 plate can advantageously replace the...report 1995
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Heida, J.H. (author), 't Hart, W.G.J. (author)An evaluation of the eddy current technique for the detection and depth assessment of corrosion around fastener holes in F-16 lower wing skins is described. The corrosion type in this structure is pitting corrosion at the countersink edge of the fastener holes. Due to a corrosion clean-up limit of only 1.5 - 2.5 %, a maximum thickness reduction...report 1994
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Schra, L. (author), 't Hart, W.G.J. (author)Corrosion tests under MASTMAASIS test conditions and alternate immersion constant load stress corrosion tests in a 3.5 % NaCl solution were carried out on 1.6 mm thick sheet material of the Al-Li alloys 2091-T84 and 8090-T81, and on the reference 2024-T3 alloy. Corrosion tests were also carried out on preproduction 2091 sheet. The results of the...report 1992
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't Hart, W.G.J. (author), Schra, L. (author)In the framework of the CEC Brite Euram programme on "Investigations on aluminium-lithium alloys for damage tolerant application", the NLR work in Task 3 concentrated on Fracture Toughness. In part I of the investigation residual strength tests were performed on 500 mm wide CCT panels of the Al-Li sheet alloys 2091-T84 and 8090-T81 and on 2024...report 1992
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- Wanhill, R.J.H. (author), Schra, L. (author), 't Hart, W.G.J. (author) report 1992
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't Hart, W.G.J. (author)The susceptibility of currently used CFRP to impact damage has stimulated the development of improved composites. This new generation of composites usually shows increased toughness and damage tolerance as well as improved tensile performance. This is generally not matched, however, by a similar improvement in compressive properties which then...report 1991
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- Wanhill, R.J.H. (author), Schra, L. (author), 't Hart, W.G.J. (author) report 1991
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Wanhill, R.J.H. (author), 't Hart, W.G.J. (author), Schra, L. (author)Since 1984 the NLR has done many fatigue crack growth tests to compare the modern Al-Li alloys 2090, 2091 and 8090 with the conventional damage tolerant alloys 2024 and 2324. Under constant amplitude loading the Al-Li alloy crack growth behaviour is often equivalent or superior to that of the conventional alloys. However, under gust spectrxim...report 1991
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Wanhill, R.J.H. (author), Schra, L. (author), 't Hart, W.J.G. (author)The fatigue crack growth properties of several aluminium-lithium (Al-Li) sheet alloys were compared with those of the widely used conventional 2024-T3 alloy. The data, which are relevant to the in-service inspectable damage tolerance regime, were obtained using constant amplitude and flight simulation (gust spectrum) loading. The Al-Li alloys...report 1991
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Schra, L. (author), 't Hart, W.G.J. (author), Boogers, J.A.M. (author)Outdoor corrosion and stress corrosion tests were conducted on AJl-Li plate and sheet materials for 3 and almost 5 years respectively.report 1990
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Schra, L. (author), 't Hart, W.G.J. (author), Boogers, J.A.M. (author)Outdoor corrosion and stress corrosion tests were conducted on Al-Li plate and sheet materials for 3 and almost 5 years respectively. The results can be summarized as follows: Corrosion: Peak aged XXXA-T651 (8090-T651) exhibited greater exfoliation corrosion resistance than 2024-T351 and 2324-T39 plate. 2091-T3 and 2024-T3 sheet were found to be...report 1990
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Wanhill, R.J.H. (author), Schra, L. (author), 't Hart, W.G.J. (author)A comparison is made of the crack resistance (R-curve), fracture toughness and instability behaviour of candidate damage tolerant aluminiumlithium alloys, 2091 and 8090, and the widely used conventional 2024-T3 alloy. The 2091 alloy was in three heat treatment conditions, T8X, TX and TY, all artificially aged. The 8090 alloy was in the T81...report 1990
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Schra, L. (author), 't Hart, W.G.J. (author)Long-term outdoor exposure tests were done to investigate the effect of cooling rate on corrosion and stress corrosion properties of extruded rods of the high strength aluminium alloys 2024-T4, 2023-T6, 7075-T6 and 7075-T73. The 2024 alloy exhibited a high susceptibility to SCC irrespective of best treatment and cooling rate, whereas 7075-T6 was...report 1990
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Wanhill, R.J.H. (author), Schra, L. (author), 't Hart, W.G.J. (author)Qualification of Al-Li alloys for damage tolerant aerospace structures requires extensive testing and evaluation. In this paper the emphasis is on fracture and fatigue crack growth properties of two candidate sheet alloys, 2091 and 8090, compared with the conventional and widely used 2024 alloy. The relative merits of these materials are...report 1990
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't Hart, W.G.J. (author), Frijns, R.H.W.M. (author)Constant amplitude tension-compression fatigue tests were performed on notched (± 45, 02, 90, 02)s coupon specimens of the composite systems T300/F593, T400H/6376, T800H//5245C and IM6/APC-2. Delamination damage growth as a function of the number of fatigue cycles was determined using the ultrasonic C-scan technique. Considering the resistance...report 1989
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Wanhill, R.J.H. (author), Schra, L. (author), 't Hart, W.G.J. (author)New impetus to continued use of alximinium alloys in major structural areas of aircraft has been given by the development of aluminium-lithium alloys. However, qualification of these new materials for service requires extensive testing and evaluation, preferably in international cooperative programmes. The evaluation of aluminium-lithium alloys...report 1989
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't Hart, W.G.J. (author)The damage development In notched (± 45, 0„, 90, 0-) carbon-epoxy coupon specimens tested under different loading conditions was determined. Constant amplitude tests at R = -1 and R = 0.1 as well as flight simulation tests were performed to establish those stress values for which no damage growth occurs.report 1988
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Schra, L. (author), 't Hart, W.G.J. (author)Long-term outdoor stress corrosion tests were executed on overaged 7000 series aluminium alloy plate and forgings. Plate material of the alloys 7010-T7651, 7010-T7451 and 7075-T7351 exhibited an excellent resistance to SCC. PM alloy X7091-T7E69 forgings combined a higher strength with superior SCC resistance as compared to IM alloy forgings. The...report 1988
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Kolkman, H.J. (author), 't Hart, W.G.J. (author), Schra, L. (author)One of the first commercially available Al-Li plate alloys, DTD XXXA-T651, produced by ALCAN International Ltd., was tested in the framework of a European cooperative programme (GARTEUR). The engineering properties were determined in a previous investigation. The present report describes the results of an additional investigation with respect to...report 1987
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Moss, A.C. (author), 't Hart, W.G.J. (author)This investigation examined carbon/epoxy and aramide/epoxy composites in interlaminar shear and in open-hole tensile tests at 90 to the unidirectional fibre orientation. Epoxy resin was also tested under tension. Photomicroscopy and the S.E.M. were used to study the fracture surfaces. Wet tests were performed to investigate the influence of...report 1986