ADAS structures module: Evaluation report

In a joint research project between the National Aerospace Laboratory (NLR) and the Faculty of Aerospace Engineering of Delft University of Technology (TUD) a multi-level system for the preliminary design of aircraft structures has been developed. The present system is essentially an extension of the existing Aircraft Design and Analysis System ...

The B2000 linear buckling processor

In many practical problems of plate and shell buckling, the pre-buckling state is linear and can be obtained from the linearized equations of elasticity. The computation of the buckling load and mode in such cases correponds to a linear eigenvalue problem that can easily be formulated and implemented in a finite element code. This report...

Damage tolerance analyses of bolt/nut assemblies

Probably one of the most challenging problems in fracture mechanics is related to its application to fastener and joints. By nature, not only the quality such as material, manufacturing and mounting processes, of the fasteners are playing a role, but also the stiffness, surface conditions and geometry of the parts are to be considered. Moreover,...

Towards digital computer simulation of the dynamics of flexible spacecraft

Software design for digital computer simulation of the dynamics of flexible spacecraft equipped with actuators and sensors, should take into account two properties of the overall system: (i) s.ampled-data control of the spacecraft leads to discontinuous inputs (forcing functions) in the differential equations of motion, thereby requiring...

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...

A finite element model to study the buckling behaviour of general orthotropic, midplane symmetric and elastic plates

A finite element model has been developed, which incorporates the bending-torsional coupling effect, as it occurs in general orthotropic, midplane symmetric, elastic plates in order to analyse its influence on the buckling behaviour of such plates. Some results have been compared with known exact and approximate solutions.

Calculation of vibration modes and resonance frequencies of the Northrop NF-5

The component mode technique is used to calculate resonance frequencies and vibration modes of the Northrop NF-5 structure. The results of the calculations are compared with those of a ground vibration test.

The nonlinear analysis part of B2000: a first evaluation

In this report a description is given of the nonlinear package of B2000. The set-up of the continuation procedure which controls the nonlinear calculations is explained. At some points the existing continuation procedure was modified to enhance its performance. The nonlinear package contains a nonlinear rod element and a nonlinear thick shell...

The use of panel methods with a view to problems in aircraft dynamics

A survey is given of the basic principles of the panel methods. The most frequently used methods, steady as well as unsteady, are described in some detail. Recent developments aiming at improvönent and extension of the range of applicability are reviewed. The use of panel methods for the determination of stability derivatives is discussed....

Application of the virtual crack closure technique to calculate stress intensity factors for through cracks with an oblique elliptical crack front

The static strenght of mechanically fastened carbon-epoxy joints without bending

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...

Finite element analyses of stable crack growh in thin sheet material

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...

An H1(Ph)-Coercive Discontinuous Galerkin Formulation for the Poisson Problem: 1-D Analysis

Discontinuous Galerkin (DG) methods are finite element techniques for the solution of partial differential equations. They allow shape functions which are discontinuous across inter-element edges. In principle, DG methods are ideally suited for hp-adaptivity, as they handle nonconforming meshes and varying-in-space polynomial-degree...

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...