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Schijve, J. (author), Broek, D. (author), Jacobs, F.A. (author)
Fatigue tests have been carried out on light alloy lugs of 2024 and 7075 material in order to investigate the effects of some geometrical parameters (lug size, geometry of lug) and various means to reduce fretting, viz. lubrication of the pin, flattened pins, slotted holes and expanded holes. Complete S-N curves have been determined at a...
report 1962
document
Hartman, A. (author), Jacobs, F.A. (author), de Rijk, P. (author)
Fatigue tests on 2024-T4 alclad double row riveted single lap joints at fluctuating tension with a mean stress in the nett section of 9.0 kg/mm2 and stress amplitudes ranging from 8.6 to 3.0 kg/mm^ did not show any significant difference in endurance of similar specimens with a size ratio li2,66.
report 1962
document
Hartman, A. (author), Jacobs, P.A. (author)
A comparison has been made between the fatigue strength at fluctuating tension of 2024-T3 alclad double row riveted single lap joints at room temperature in the as fabricated condition and at 150°C after stress-aging at this temperature for 100 hours. The tests showed an appreciable decrease in endurance of the specimens tested at 150°C,...
report 1963
document
Hartman, A. (author), Jacobs, F.A. (author)
The propagation has been studied of fatigue cracks in 2024-T3 alclad sheet under fluctuating tension in different atmospheres. Of the principal constituents of air water vapour had a much more severe effect than oxygen; in wet -pure argon the endurance was much shorter than in dry pure oxygen. In air, other circumstances remaining unaltered, the...
report 1964
document
Schijve, J. (author), Jacobs, F.A. (author)
Constant-amplitude tests and programme tests were carried out on 2024-T3 lug specimens with standard holes, slotted holes and expanded holes. The results give information on (1) programme loading versus constant-amplitude loading, (2) cumulative damage and (3) the improvement of the fatigue endurance obtained by the application of slotted and of...
report 1964
document
Schijve, J. (author), Nederveen, A. (author), Jacobs, F.A. (author)
The size effect on crack propagation was studied with sheet specimens of 2024-T3 Alclad. Values of the width were 80, 160, 300 and 600 mm, sheet thickness 3 mm, mean stress 8 kg/mm2 and stress amplitudes 2.5, 4 and 6.5 kg/mm2. Results are compared with the theory of the stress intensity factor and the Weibull theory. Practical implications of...
report 1965
document
Hartman, A. (author), Jacobs, F.A. (author), van der Vet, W.J. (author)
report 1965
document
Hartman, A. (author), Jacobs, F.A. (author), van der Vet, W.J. (author)
Several single lap Joints in clad 2024-T3 and 7075-T6 alitainium alloy with two rows of rivets or Huclcbolts have been evaluated in respect of their fatigue strength properties, both in tests with constant load amplitude and in tests with a programmed load sequence based on a gust spectrum. The results showed that: 1) The replacement of...
report 1965
document
Broek, D. (author), Jacobs, F.A. (author)
Static tests were carried out on 280 mildly notched specimens of various aluminium alloys. It appears that the nett section fracture stress as a percentage of the ultimate tensile strength is in general higher for materials of lower ductility. This influence of ductility can be reasonably explained on the basis of measured plastic strain...
report 1965
document
Hartman, A. (author), Jacobs, F.A. (author), Nederveen, A. (author), de Rijk, P. (author)
The investigation on the propagation of fatigue cracks in aluminium alloy sheet under fluctuating tension comprised four parts. (1) Tests to determine the combined effects of the humidity of the air and the lead frequency (clad 2024-T3 and 7075-T6). (2) Tests to determine the effect of water. (3) Tests to determine the effect of wetting with a...
report 1967
document
Schijve, J. (author), Jacobs, F.A. (author)
report 1968
document
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
document
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
document
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
document
de Graaf, E.A.B. (author), Jacobs, F.A. (author), Nassette, J.H. (author)
This investigation is a comparative study of different types of mechanical surface treatments with the objective of achieving residual compressive stresses at the surface of the test specimen. The fatigue behaviour of these treated specimens in constant amplitude tests and programme tests is dealt with. The benefit of the various treatments for...
report 1971
document
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
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
document
't Hart, W.G.J. (author), Jacobs, F.A. (author), Nassette, J.H. (author)
report 1975
document
Wanhill, R.J.H. (author), Schijve, J. (author), Jacobs, F.A. (author), Schra, L. (author)
The following text is given in the format required for presentation at the Conference and Exhibition "Fatigue Testing and Design", to be held in the City University, London, 5-9 April 1976. The report gives a comparison between the fatigue performances of several sheet and forging materials under gust spectrum loading representing the lower wing...
report 1975
document
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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