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Wanhill, R.J.H. (author), Schra, L. (author)An investigation was made of the effect of starter notch geometry on flight simulation fatigue crack growth in three damage tolerant aluminium sheet alloys, 2024-T3, 2091-T84 and 8090-T81. Changing the starter notch geometry resulted in significant differences in initial nonstabilized fatigue crack growth behaviour. However, there was only a...report 1995
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Wanhill, R.J.H. (author), Schra, L. (author), 't Hart, W.G.J. (author)This report compares the mechanical properties, fracture toughness and fatigue crack growth properties of the damage tolerant/medium strength aluminium plate alloys 2024-T351, 2324-T39, 8090-T651 and 8090-T8171. The main objective, in view of previous work, was to determine whether damage tolerant 8090-T8171 plate can advantageously replace the...report 1995
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- de Jonge, J.B. (author), Hol, P.A. (author), van Gelder, P.A. (author) report 1995
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Noback, R. (author)Aspects of the requirements for and the calculation of design loads due to atmospheric disturbances are discussed. Special attention has been paid to the relation between discrete gusts and continuous turbulence. It is recommended that a worst case gust model, as described in this report, be further developed.report 1993
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Noback, R. (author)A worst case gust shape has been derived for turbulence or gust patches, assuming only that the average spectrum of such patches is known. The maximum value of the response can be calculated quite easily. The result differs from the PSD-method. Some examples of worst case inputs and outputs are given, also for nonlinear systems.report 1993
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ten Have, A.A. (author)WISPER and WISPERX are standardised variable-amplitude test loading histories for use in the fatigue design of horizontal axis wind turbine blades. They are based on flap load service measurements on 9 different horizontal axis wind turbines, covering a wide range of materials, rotor diameters and geographical locations. The present report is...report 1992
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Noback, R. (author)The Deterministic Power-Spectral-Density method can be derived from the Design Envelope Analysis of the continuous P.S.D.-method. It provides a method to determine a deterministic function that gives a maximum response equal to the P.S.D.-design load for linear systems. The P.S.D.-design load is undefined for nonlinear systems. In this report a ...report 1992
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Noback, N. (author)The Deterministic Power-Spectral-Density-method has been derived directly from the continuous P.S.D.-method. It can be regarded as a "translation" from the frequency domain to the space or time domain. The critical gust profile, giving maximum response, is obtained directly. The D.P.S.D.-method gives the same results as the continuous P.S.D.-...report 1992
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de Jonge, J.B. (author), Bartelds, G. (author)The problems of Ageing Aircraft are worldwide. Hence, actions to overcome or prevent these problems should be taken in international collaboration. The Federal Aviation Administration FAA and the Netherlands Civil Aviation Department RLD have signed a Memorandum of Cooperation in the area of structural integrity, with specific reference to...report 1991
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Schra, L. (author), Wanhill, R.J.H. (author)Flight simulation fatigue growth tests were done on 1.6 mm thick sheets of the damage tolerant aluminium-lithium (Al-Li) alloys 2091-T84 and 8090-T81 in comparison with the industry standard conventional damage tolerant alloy 2024-T3. The flight simulation load spectrum, the gust spectrum MINITWIST, was used in four versions: untruncated,...report 1991
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Noback, R. (author)Equations for the response of an aircraft to two-dimensional vertical atmospheric turbulence have been derived, both for an aircraft regarded as a continuous system and for an aircraft split up into a number of panels. These equations have been applied to an aircraft model with two degrees of freedom of the size of the Fokker 100, respectively....report 1991
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Noback, R. (author)The Power Spectral Density (P.S.D.)-method is used to define design loads due to atmospheric turbulence. The design loads are calculated using linear transfer functions. These methods can not be used if the equations describing the behaviour of the aircraft are nonlinear. One method to define design loads for a nonlinear aircraft is by means of...report 1989
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Noback, R. (author)A method is described to generate a random Gaussian process with a power spectrum with fractional power, for example the von Karman spectrum for atmospheric turbulence. The method uses digital filtering of a white noise process and it is based on the use of fractional derivatives. An algorithm to generate the process is presented.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
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Noback, R. (author)Measured time histories of atmospheric turbulence have been analysed. Distribution functions and exceedance curves of the turbulence and its derivative are presented. The load exceedance curves of various mathematical airplane models due to these turbulence patches have been calculated. Deviations of the properties of these patches from the...report 1988
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Noback, R. (author)This report gives an outline of the method to generate equal probility design load conditions. The various steps are described.report 1985
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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
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de Jonge, J.B. (author)The present course book has been prepared as lecture notes for a summer course given at the Technical University of Bandung (ITB) in the summer of 1984. This course took place within the framework of the TTA-79 Technical Assistance Project as agreed between the Governments of Indonesia and the Netherlands. The subjects of the course are listed...report 1984
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Noback, R. (author)Historical reviews of the discrete gust and the continious gust concept, in relation to the present requirements, are given in this report. A comparison is made between the discrete gust method and the power spectral density method on the basis of simple airplane models. No direct relation between the two methods exists. The main cause of the...report 1982
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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