Prediction of thermal expansion coefficients of sandwiches using finite elements methods validated by experimental test results

Abstract

The new generation of telecommunication antennas for space applications working at frequencies above 20 GHz (which will be generally manufactured by sandwich structures) needs an accurate thermostructural design due to the envisaged increase of the dimensions of the reflectors and the related decrease of the required RMS thermal distortion. In an integrated design which takes into account the reciprocal influence of thermal and structural aspects, the thermal expansion coefficient (C.T.E.) of the structures which are part of the reflector assembly, is a very important parameter. A good prediction of this value is a contribution to an accurate estimate of the electrical performance of the antenna system in the space environment. This work describes a prediction method to evaluate the C.T.E. of a sandwich validated by some experimental results and checked by an analytical study. Numerical results illustrate the procedures; graphs and appendices complete the work.