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document
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
document
Schijve, J. (author), Jacobs, F.A. (author)
Fatigue tests were carried out on Redux and FM 123/5 bonded specimens at various stress levels, temperatures (RT to 65 C) and low and high test frequencies. Observations were made on the type of failure (bond line failure or sheet failure) and the significance of the adhesive squeezeout for crack nucleation. An analysis of the data and a...
report 1984
document
Schra, L. (author), van Leeuwen, H.P. (author)
The influence of previous corrosion on the fatigue life was investigated. It was foimd that a slight corrosive attack could drastically reduce the fatigue life. The damaging effect of corrosion was greater for the alloy AA 7050 than for AZ 74.61. It could be established that fatigue cracks initiated from various corrosion pits. A second series...
report 1977
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
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)
Residual strength tests have heen performed, on 300 mm wide centrecracked panels of various thicknesses, at room temperature and at -50 C. During the tests, stable crack growth was filmed and recorded with the electric potential method. Fracture toughness was determined using the method of Feddersen.
report 1976
document
Kolkman, H.J. (author)
Differences in the fatigue crack propagation rates of 2024-T351 and 2324-T39 are explicable from differences in microstructures. The slope changes (transitions) in the crack propagation curves are probably associated with the plastic zone sizes being equal to certain microstructural dimensions. As a consequence of different chemical compostion...
report 1985
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
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
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
't Hart, W.G.J. (author)
Fatigue tests on unidirectional Ca/ep composite material have been performed to investigate whether previous fatigue loading did influence the residual static strength. Residual strength tests were carried out on (0, ± 45)2s and (± 45)2s laminates, while for the (O, ± 45)2s laminate the influence of previous tensile fatigue loading on the...
report 1977
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
Schra, L. (author), Kolkman, H.J. (author)
The SCC resistances of three damage tolerant aluminium sheet materials were determined by means of the ASCOR (Automated Stress COrrosion Ring) test. The conventional damage tolerant sheet material 2024-T3 was used as reference. The SCC resistance of 8090-T81 turned out to be only slightly lower than the SCC resistance of 2024-T3. In contrast,...
report 1991
document
de Koning, A.U. (author)
This study deals with fracture mechanics aspects of mode 1 crack growth under montonically increasing (quasi-static) loads. Using the finite element method stable crack growth and the plastic deformation fields associated with this process are analyzed. A two parameter approach is proposed for a description of initiation and subsequent stable...
report 1985
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