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Richmond, M.J. (author), de Koning, A.U. (author)
Utilising the NLR Stripyield cycle-by-cycle fatigue crack growth model a basic description of the time dependent effects associated with periods of constant load level has been added to model Fatigue-Creep interactions. An outline of the basic Creep model is given along with flow diagrams of the sub programs added to the Stripyield model. Other...
report 1993
document
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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Oldersma, A. (author)
Composite materials with more than one type of fiber in one matrix are known as hybrid composites. In this work the fatigue behaviour of composite materials is discussed and the behaviour of hybrid composites is related to simple (single-fiber) composites. The properties and the behaviour of hybrid composites can mostly be explained...
report 1991
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't Hart, W.G.J. (author)
The susceptibility of currently used CFRP to impact damage has stimulated the development of improved composites. This new generation of composites usually shows increased toughness and damage tolerance as well as improved tensile performance. This is generally not matched, however, by a similar improvement in compressive properties which then...
report 1991
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Lameris, J. (author)
In the full scale durability and damage tolerance tests of composite aircraft structures, the US and European certification requirements demand among other things that the number of cycles applied are statistically significant and that the influence of the environment has been taken into account. Several certification methods are described which...
report 1990
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't Hart, W.G.J. (author), Frijns, R.H.W.M. (author)
Constant amplitude tension-compression fatigue tests were performed on notched (± 45, 02, 90, 02)s coupon specimens of the composite systems T300/F593, T400H/6376, T800H//5245C and IM6/APC-2. Delamination damage growth as a function of the number of fatigue cycles was determined using the ultrasonic C-scan technique. Considering the resistance...
report 1989
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Laméris, J. (author), Minderhoud, P. (author)
The mechanical behaviour of mechanically fastened double lap carbon-epoxy joints has been investigated both by experiments (static tests) and by analysis. Several fastener types and joint geometries has been investigated. In the experimental programme the Fibredux 6376/T400H material was used. Two methods to analyze mechanically fastened...
report 1989
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van der Hoeven, W. (author)
report 1988
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't Hart, W.G.J. (author)
The damage development In notched (± 45, 0„, 90, 0-) carbon-epoxy coupon specimens tested under different loading conditions was determined. Constant amplitude tests at R = -1 and R = 0.1 as well as flight simulation tests were performed to establish those stress values for which no damage growth occurs.
report 1988
document
de Koning, A.U. (author), Liefting, G. (author)
The crack opening behaviour of a fatigue crack in a centrally cracked panel was studied using a discretised version of the Dugdale and Barenblatt model. The effect of crack growth was also included. Results obtain ed for constant amplitude loading were in agreement with data reported in the open literature. The effect of application of single...
report 1986
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Komorowski, J.P. (author)
This report is the first in a series of literature reviews in which hygrothermal effects on aerospace composite materials (CM) are examined. This first report (Part I) deals primarily with fundamental aspects of the diffusion of moisture into, and from, composite materials. The effects of temperature under both steady state and transient...
report 1983
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van Leeuwen, H.P. (author)
The literature concerning the application of fracture mechanics to the growth of creep cracks is discussed. As an introduction it is shown that linear elastic fracture mechanics have been applied successfully to the residual strength of brittle materials crack growth due to stress corrosion and crack growth due to fatigue. Next the methods are...
report 1983
document
de Koning, A.U. (author)
In this report formulas are derived for a description of the deformation and stress fields near holes expanded by cold working. The results are compared with values obtained experimentally and calculated using the finite element method. The model of the material includes linear hardening and a yielding behaviour according to Tresca's criterion....
report 1982
document
Wanhill, R.J.H. (author)
Flight simulation fatigue crack propagation tests with gust spectrum loading were carried out on laminates of (i) aluminium alloy 2024-T3/carbon-epoxy, (ii) aluminium alloy 7475-T761/carbon-epoxy and (iii) titanium alloy Ti-6Al-4V/carbon-epoxy with nominal weight savings of 30% and 40% as compared to equivalent 2024-T3 Alclad and 7475-T761...
report 1982
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't Hart, W.G.J. (author)
An experimental investigation was performed to examine the effect of low energy impact damage on tension-compression fatigue properties of sandwich panels. The specimens consisted of a 9 mm thick Nomex honeycomb and face sheets of (0,± 45) and (± 45,0) Carbon/epoxy. Drop weight impact was applied to create internal laminate damage. In order to...
report 1981
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de Graaf, E.A.B. (author), Rienks, K.J. (author), van Dreumel, W.H.M. (author)
The present report describes the X-ray radiography and subsequent destructive investigation according to metallographic techniques of specimens that were taken from experimental mixed—laminate test panels. Clues for the interpretation of radiopraphs of carbon fibre reinforced composites are given.
report 1980
document
Ko1kman, H.J. (author)
Plastic deformation of f.c.c. single crystals was studied by means of straining experiments inside a transmission electron microscope on Cu foils and some related bulk straining experiments on Cu and Al single crystals. In the foils and bulk crystals with the same orientation of the normal to the large face the same non-primary glide...
report 1980
document
de Koning, A.U. (author)
In the present report a simple analytical model for the "behaviour of a centrally cracked strip is proposed. Formulae for computation of compliance, crack opening displacement and effective crack extension force are derived. The model is based on the classical solution for a crack infinite sheet under uniaxial tension. The effect of finite...
report 1979
document
van den Assem, D. (author), Daniels, D.H.W. (author)
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
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