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't Hart, W.G.J. (author)A microscopic study has been performed on carbon composite fracture surfaces, using the Scanning Electron Microscope (SEM). It appears that the SEM is a useful tool to examine the fracture surface characteristics of composite materials failing under different loading conditions.report 1976
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Vlieger, H. (author)Residual strength tests were carried out on center-cracked panels with a 2024-T3 or 7075-T6 skin and provided with eccentric stiffeners of practical design. The stiffeners were riveted to the skin. The material of the stiffeners was 7075-T6. In some cases the stiffeners were combined with Ti-alloy crack stoppers. On the basis of the test results...report 1976
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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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- Bartelds, G. (author) report 1978
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Vlieger, H. (author)Past experience has shown that during the operational life of an aircraft structure cracks or failures may arise in different structural components. In future designs the designer must be able on the one hand to restrict the occurrence of cracks by a careful detail design and on the other hand to guarantee some specified life of the aircraft if...report 1976
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Wanhill, R.J.H. (author)This report contains the overhead sheets of a short course on fatigue and fracture of aerospace aluminium alloys, plus an annex in the form of a review paper.report 1994
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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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Lof, C.J. (author)Computer programs are described to be used for fracture control purposes. Crack growth lifetimes can be predicted for plane cracks in 3-D structures. Values for stress intensity (K-) distributions at crack fronts are derived from data being available from literature for a restricted number of simple configurations. For arbitrary configurations...report 1986
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van der Hoeven, W. (author)The effect of cooling rate on some mechanical properties of APC-2/AS4 composite was investigated over the range between 1 and 70° C/min. Preconsolidated unidirectional laminates were reprocessed in a hot platen press at controlled cooling rates. Double Cantilever Beam specimens and End Notch Flexure specimens were used to determine the mode I...report 1993
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Bartelds, G. (author), Nederveen, A. (author)Aluminium sandwich paaiels provided with carbon-epoxy uniaxial reinforcing strips were fatigued and subsequently tested for residual strength, Although both analysis ajid fatigue tests indicate that the crack tip zone is affected onlywhen the zone is in the immediate vicinity of a stiffener the reinforcement considerably increases crack...report 1974
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Vlieger, H. (author)This report presents results of residual strength calculations, carried out on cracked panel configurations of various designs and provided with bonded stiffeners. The calculations were carried out using the computer program BOND. The results of these calculations are compared with results of residual strength tests, performed on panels of...report 1983
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Schra, L. (author), van Leeuwen, H.P. (author)The effect of variety of heat treatments on various engineering properties was studied with the aim to derive an optimum heat treatment. The engineering properties comprised Vickers hardness, short-time tensile strength, fatigue crack propagation resistance, fracture toughness and stress corrosion resistance. The test results were compared with...report 1976
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- Chen, D. (author) report 1990
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van Gestel, G.F.J.A. (author)In this report an attempt is made to give an overview of the various aspects involved in a fracture surface investigation, stating with a definition of fractography and why it is done. Then the equipment needed is discussed, including stereo-microscopes, optical microscopes, transmission and scanning electron microscopes, and micro-analysis...report 1977
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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)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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Lameris, J. (author)Fracture toughness measurements were carried out to test the ageing behaviour of three adhesives in different environments. It was possible to compare and evaluate adhesives and surface pretreatments. It is doubtful whether the derived R-curves could be used for residual strength calculations in certain environments. Phosphoric acid anodizing...report 1978
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Wanhill, R.J.H. (author), Schra, L. (author)The effects of flat to slant fracture transitions on flight simulation fatigue crack propagation in specimens of 7O5O aluminium alloy forgings are discussed. For specimens containing flat, shearlipped, or full slant fractures at similar crack lengths the crack resistance (R curve) approach appears to provide an explanation for differences in the...report 1976
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Wanhill, R.J.H. (author), Schra, L. (author)Engineering properties of the PM alloy 7091-T7E69 and the IM alloys 7075-T73, 7175-T736, 7010-T736 and 7050-T736 were compared. The properties considered were strength, fracture toughness, fatigue strength, fatigue crack propagation resistance under constant amplitude and spectrum loading, stress corrosion crack initiation and propagation...report 1983
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Schra, L. (author), 't Hart, W.G.J. (author)Engineering property comparisons have been made for plate material of the newly developed aluminium alloy 2324-T39 and the widely used alloy 2024-T351. The properties considered were: tensile strength, fracture toughness, notched fatigue strength, and the resistance to fatigue crack propagation under both constant amplitude and flight simulation...report 1984