A study on methods to compare measured and calculated modal data

Fokker Space and Systems and the National Aerospace Laboratory NLR performed a study to integrate more systematically the experimental and analytical analysis of the dynamic behaviour of structures. The study focused on the correlation of experimental and analytical data, matrix and parameter updating methods. In this paper an overview will be...

The deterministic power-spectral-density-method for nonlinear systems

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 ...

The deterministic power-spectral-density-method for linear systems

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.-...

The response of aircraft to two-dimensional vertical turbulence

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....

Correlation, error-localisation and updating of the second problem defined in GARTEUR AG11

A description is given of the second problem, a clamped-free truss structure, defined in the GARTEUR Action Group 11. The measured and calculated modal data of the structure are correlated, the locations of the errors are determined and finally the finite element model of the structure is updated. These analyses are performed with the B2000...

Influence of reduction and interpolation methods on the correlation of calculated and measured modal data of a solar array

At Fokker Space and Systems the measured and calculated modal data of an ARA 3-panel-clean-wing were correlated. The number of degrees of freedom (dof's) of the finite element model (FEM) is about 6400 and of the measurement 32. Three methods were used to obtain corresponding dof's namely: 1) the number of dof's of the FEM was reduced with a...

Atmospheric turbulence spectra and correlation functions

The derivation of one- two- and three-dimensional spectra and correlation functions for isotropic (atmospheric) turbulence and the mutual relations have been collected from various sources. Aircraft loads usually are determined using a one-dimensional turbulence description. In some cases a two- or even three-dimensional description might be...

A new method for matching stacked seismic data with well log information

Activated dynamics in a two-dimensional Ising spin glass: Rubidium copper cobalt fluoride (Rb2Cu1-xCoxF4)

CAR 88: A method to calculate subsonic and supersonic, steady and unsteady, potential flow about complex configurations

A description is given of the method CAR88 for the calculation of steady and time-linearized unsteady subsonic and supersonic flow about complex 2-D and 3-D configurations. The method belongs to the category of the socalled panel methods. Results of applications in supersonic flow are shown which have been made to a 2-D oscillating flat plate, a...

Breakup of long-range order in the diluted antiferromagnet K2MnxZn1-xF4 in zero magnetic field

How to generate equal probability design load conditions

This report gives an outline of the method to generate equal probility design load conditions. The various steps are described.

Fatigue Rated Fastener Systems: an AGARD coordinated testing programme

The report contains the description, results and conclusions of a fatigue test programme which assessed the fatigue lives of fastener systems using different joints. High load transfer single shear joints were evaluated in a core programme; secondary bending and load transfer were determined experimentally. About 750 specimens were fatigue...

The generation of equal probability design load conditions, using P.S.D.-techniques

A method is derived to generate consistent sets of design load conditions if aircraft design loads are determined using the Design Envelope criterion of the Power Spectral Density (P.S.D.)-method. The method is based on the use of the correlation coefficients between the various loads. Two sets of design load conditions have special properties...

A system for the numerical simulation of sub- and transonic viscous attached flows around wing-body configurations

A description will be presented of a computer program system that is being used for the prediction of aircraft steady aerodynamic characteristics. Properties of the system are described from two different viewpoints. One is that of the aerodynamic designer, who needs an information system to predict lift, moment and drag characteristics and to...

Correlation-Function Techniques: An analysis of their performance and capabilities

The interest in correlation-function techniques shown by a number of groups working at the RWS is mainly due to the two following reasons: 1) Boundary-values determination and 2) Prediction. For these reasons, preliminary studies were undertaken some time ago at RWS. As part of these studies, correlation functions between a number of stations on...

A statistical method for error reduction in an integration process involving experimental data

The numerical integration of a non-linear function f(a (t), ap(t),.. a (t)) vith mutually independent variaties a, is considered for the case that the initial conditions for the integration process and time series of a, are determined by experiment. In order to minimize the error in the result of the integration process a technique is developed...