Abstract
A new generation of large space structures (LSS), remotely deployed and stationed at geosynchronous equatorial orbit, is currently being considered for use in terrestial communications networks. These skeletal structures, which would be manufactured from high technology thermoplastics composite materials, would include multi-functional large scale platforms on which a variety of reflector assemblies would be attached. A scaled perspex model of a proposed LSS has been constructed and an experimental examination of its modal behaviour in simulated unrestrained conditions has been undertaken. These results have been used to establish the level of agreement it is possible to obtain from natural frequency extractions of the structure modelled using the finite element method. Both impact and sine dwell testing techniques have been applied in determining the modal responses of the model and it has been found that selection of the most appropriate method should be made in consideration of its anticipated modal behaviour. Very good agreement has been found between the frequency characteristics obtained experimentally analytical and frequency extractions for this model, although both methods have been hampered by the presence of the flexible arrays which have been modally active in the frequency ranges of interest. The results of this study have demonstrated that a measure of confidence can be placed on similar parametric studies on large scale unrestrained skeletal structures using the finite element method.
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