- document
-
de Graaf, E.A.B. (author), de Rijk, P. (author)The present report describes how fatigue cracks were produced in 102 specimens. After cracking these specimens were inspected non-destructively by means of eddy currents, ultrasonics. X-rays and penetrants, and the indications were recorded. Successively the specimens were exposed to corrosion whereafter the inspections were repeated. Upon...report 1978
- document
-
Schijve, J. (author), Jacons, F.A. (author), Meulman, A.E. (author)Flight simulation tests on 2024-T3 and 7075-T6 lug specimens indicated significant fatigue life improvements obtained by expanding the holes in accordance with the split-sleeve cold work method. Geometrical distortions induced by the expansion were measured. The significance of residual stresses is analysed with reference to depth of penetration...report 1978
- document
-
Wanhill, R.J.H. (author)Flight simulation fatigue crack propagation tests with gust spectrum loading were carried out on 2024-T3/carbon-epoxy, 7475-T76l/carbon-epoxy and Ti-6Al-4V/carbon-epoxy laminates with nominal weight savings of -30% as compared to equivalent 2024-T3 panels. The performance of the 2024-T3/carbon-epoxy laminates was much superior to those of the...report 1978
- document
-
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
- document
-
Wanhill, R.J.H. (author)2024-T3, 2048-T851, 7075-T6 and 7475-T761 aluminium alloy sheets were compared for fatigue crack propagation resistance under manoeuvre spectrum and constant amplitude loading. For manoeuvre spectrum loading 7475-T761 was superior overall, and this superiority is most probably due to superior toughness of this alloy. In more detail, 2024-T3 was...report 1978
- document
- Wanhill, R.J.H. (author) report 1978
- document
-
de Rijk, P. (author), Schijve, J. (author)A second series of exploratory acoustic fatigue tests using a shaker. A second series of exploratory acoustic fatigue tests was carried out, again employing simple specimens mounted on a shaker. Strain measurements were compared with calculations. Crack growth initiated by a central notch was observed. A comparison was made between three types...report 1977
- document
-
Wanhill, R.J.H. (author)Plight simulation fatigue crack propagation tests with gust spectrum loading were carried out on 2024-T3/carbon-epoxy, 7475-T761/carbon-epoxy and Ti-6Al-4V/carbon-epoxy laminates with nominal weight savings of 30% as compared to equivalent 2024-T3 panels. The performance of the 2024-T3/ carbon-epoxy laminates was much superior to those of the...report 1977
- document
-
Wanhill, R.J.H. (author)This paper concisely reviews and discusses (1) metallurgically cleaner alloys like -2124, 2048 and 7475, (2) potential application of 7000 series alloys in tension panels, (3) development of high strength stress corrosion resistant thick section materials like 7010, 7049 and 705O, (4) powder metallurgy 7000 series alloys with high strength and...report 1977
- document
-
Wanhill, R.J.H. (author)Flight simulation fatigue crack propagation tests were carried out on 2024-T3, 7475-T761 and mill annealed Ti-6A1-4V sheet in thicknesses up to 3 nim and representative for traJisport aircraft lower wing skin stiffened panels of end load capacities 1.5 and 3 MN/m. There was a significant effect of sheet thickness on crack propagation. Thinner...report 1977
- document
-
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
- document
-
Wanhill, R.J.H. (author)Flight simulation fatigu-e crack propagation tests were carried out on 2024-T3, 7475-T761 and mill annealed Ti-6A1-4V sheet in thicknesses up to 3 miri and representative for transport aircraft lower wing skin stiffened panels of end load capacities 1.5 and 3 MN/m. The performance of 2024-T3 was much superior, owing mainly to greater retardation...report 1977
- document
-
Schra, L. (author), van Leeuwen, H.P. (author), Meulman, A.E. (author)The fatigue crack propagation performance of the alloy AZ 74.61 under manoeuvre spectrum loading was studied. The crack propagation behaviour was also compared with that of the American forging alloy AA 7050, not only for simulated manoeuvre loading but also for simulated gust loading and programme loading. It was found that, at comparable...report 1976
- document
-
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
- document
-
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
- document
-
't Hart, W.G.J. (author)Some residual strength tests have been performed on 610 mm wide centre-cracked panels at a temperature of -50 C, in order to examine whether equal Ke values are obtained as for 300 mm wide panels, tested at -50°C. This work is a continuation of the residual strength investigation reported in NLR TR 76103 and NLR TR 75168.report 1976
- document
-
van Leeuwen, H.P. (author), Schra, L. (author)The literature is reviewed with respect to: - tests conducted to investigate crack re-initiation under dynamic load and arrest of a running crack - metallurgical sources of rate effects - available data for aerospace engineering materials - mechanical sources of rate effects, i.e. dynamic crack tip stresses and kinetic energy effects Conclusions...report 1975
- document
-
'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
- document
-
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
- document
-
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