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Vink, W.J. (author), de Jonge, J.B. (author)
The present report is part of a "Manual" on aircraft loads, that is being prepared by NLR. It contains a computer program, to be used in combination with "MATLAB4 for Windows" (Student Edition) software, to study aircraft loading due to turbulence. It includes a simple aircraft response model with two rigid and three flexible symmetric degrees...
report 1997
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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
document
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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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)
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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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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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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de Jonge, J.B. (author)
The report starts with a general review of the loading of transport aircraft fuselages and the consequent fuselage skin stresses Taking the F-28 fuselage as an example, the potential weight savings that can be obtained by using ARALL as skin material are assessed. The report ends with conclusions and recommendations
report 1982
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Wanhill, R.J.H. (author), Jongebreur, A.A. (author), Morgan, E. (author), Moolhuijsen, E.J. (author)
Flight simulation fatigue crack propagation tests on single and double element lugs made from 2024-T351 and TOT5-TT351 aluminium alloys and Ti-6AJ.-UV titanium alloy were carried out. Initial damage was a throughthickness notch at one side of each hole in one element. Results showed that crack propagation lives for double element lugs were much...
report 1981
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de Koning, A.U. (author), van der Linden, H.H. (author)
A model for the prediction of growth rates of fatigue cracks in aluminium alloys subjected to service loading conditions is presented. The model is based on an approximate description of the crack opening behaviour and was applied successfully in an analysis of effects of crack growth acceleration and retardation observed experimentally under...
report 1981
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Noback, R. (author), Blaauboer, C. (author)
Design loads for nonlinear aircraft, i.e. aircraft with gust alleviation system or yaw dampler, cannot be established with the Power Spectral Density method. The only method available is by means of computer simvilation. Methods to approximate load exceedance curves of nonlinear aircraft are proposed in this report. For the derivation of the...
report 1980
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Wanhill, R.J.H. (author)
Flight simulation fatigue crack propagation tests on 202U-T3 and 7475-T761 aluminum alloy sheet were carried out using a gust spectrum representative of the load history of an under wing skin in a transport aircraft. The investigation included tests at several design stress levels and in environments of laboratory air and air plus water spray....
report 1980
document
de Jonge, J.B. (author)
Due to the development of servo hydraulic fatigue testing machines, fatigue tests under realistic loading conditions have become possible. In these tests, standardized load sequences can be applied. The paper describes the main properties of such sequences, including TWIST and FALSTAFF. Various examples of application of these sequences are...
report 1980
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Schijve, J. (author)
Paper presented at the 16th ICAP Conference, Brussels, 14 and 15 May 1979.
report 1979
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de Jonge, J.B. (author)
The paper starts with a general discussion on various aspects of life re-assessment. Specific attention is paid to the possibility of re-assesgrnent by means of comparative fatigue tests on specimens. As an illustration of this method, the paper gives a description of the life-re-assessment procedures applied by the Royal Netherlands Airforce...
report 1979
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
Noback, R. (author)
In this report it is assumed that atmospheric turbulence appears in patches and that within the patches the turbulence can be described.as a modulated Gaussian process. The patch lengths have a certain probability density function. Load exceedance curves and design loads for various aircraft models for this turbulence model are compared with...
report 1978
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