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Schra, L. (author), Wanhill, R.J.H. (author)Flight simulation fatigue growth tests were done on 1.6 mm thick sheets of the damage tolerant aluminium-lithium (Al-Li) alloys 2091-T84 and 8090-T81 in comparison with the industry standard conventional damage tolerant alloy 2024-T3. The flight simulation load spectrum, the gust spectrum MINITWIST, was used in four versions: untruncated,...report 1991
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Wanhill, R.J.H. (author), Looije, C.E.W. (author)The constant amplitude and flight simulation (TURBISTAN) fatigue crack growth behaviour of Ti-6A1-4V fan disc forgings tested in the AGARD engine disc cooperative test programme was investigated by fractographic and microstructural analysis. The crack growth curve shapes and fractographic characteristics were similar. Transitions in the fatigue...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) 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)Sustained load fracture control is a problem of particular importance for manned spacecraft and orbital stations, owing to the long design lives and limited opportunities for repair. The current ESA approach Is based on screening out materials shown to be susceptible to stress corrosion cracking (SCC) from smooth specimen tests. This approach...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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Wanhill, R.J.H. (author)This document provides guidelines for obtaining and using stress corrosion cracking (SCC) test data for high strength alloys, which are used typically in aerospace structures. Both fracture mechanics and non-fracture mechanics tests are considered, but the emphasis is on using fracture mechanics as part of an overall strategy - a fracture...report 1991
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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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Wanhill, R.J.H. (author)Paper presented at the International Conference on Advanced Aluminium and Magnesium Alloys, Amsterdam, 20-22 June 1990. Modern Al-Li alloy development is motivated by prospective weight savings owing to decreased density and increased stiffness as compared with conventional alloys. Improvements in density and stiffness are joint consequences of...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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- Wanhill, R.J.H. (author), Schra, L. (author) report 1989
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Wanhill, R.J.H. (author)An example test plan for sustained load fracture control verification is presented. Two sustained load fracture problems have been chosen: stress corrosion cracking of titanium alloy Ti-6Al-4V, and gaseous hydrogen embrittlement of the nickel-base superalloy Inconel 718. The plan is worked out in detail, including materials and heat treatments,...report 1989
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Wanhill, R.J.H. (author)The opportunities for sustained load fracture control in spacecraft are indicated. Emphasis is given to verification by small-scale laboratory testing.report 1989
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Wanhill, R.J.H. (author)The opportunities for sustained load fracture control in spacecraft are indicated. Emphasis is given to verification by small-scale laboratory testing.report 1989
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Wanhill, R.J.H. (author), Mom, A.J.A. (author), Hersbach, H.J.C. (author), Kool, G.A. (author), Boogers, J.A.M. (author)The NLR has two high velocity burner rigs for oxidation and hot corrosion testing. A large, custom-built rig was commissioned in 1977 to enable actual components to be tested. A smaller rig for specimen testing was purchased in 1986. Experience with these rigs over the last decade is reviewed.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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Wanhill, R.J.H. (author), Schra, L. (author)The economic life of airframes is largely determined by widespread initiation and growth of fatigue cracks at low stress intensities. Any factor reducing the low stress intensity fatigue damage rate could, if controllable, increase the structural durability. One such factor is corrosion fatigue crack arrest. Corrosion product build-up within a...report 1988
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Wanhill, R.J.H. (author), Galatolo, R. (author), Looije, C.E.W. (author)The constant amplitude fatigue crack growth behaviour of a conventionally (alpha ß) solution treated and aged Ti-6A1-4V fan disc forging was examined by fractographlc and microstructural analysis. The crack growth process was complex with many Interrelated fracture features. A transition in the fatigue crack growth curve correlated with a change...report 1988
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Wanhill, R.J.H. (author)The actual and potential uses of fracture mechanics to characterize stress corrosion cracking and to provide stress corrosion fracture control in engineering structures are discussed.report 1988