A.S. Evdokimov - Ph. D. (Phys.-Math.), Engineer, JSC Academician M.F. Reshetnev «ISS» (Zheleznogorsk). E-mail: eas1985@mail.ru D.O. Shendalev - Ph. D. (Eng.), Head of Group, JSC Academician M.F. Reshetnev «ISS» (Zheleznogorsk). E-mail: shendalev_d@iss-reshetnev.ru

Space-based large deployable antennas are used in lots of applications including telecommunication, broadcasting, earth remote sensing, deep space explorations, space reconnaissance etc. Achieving of desired properties is exacerbated by high cost and complexity of testing. At the same time mathematical modeling is becoming the only way to asses and to prove functional properties. The key problem in building such model is verification. In particular, for large mesh reflector facet sagging due to gravity can be higher than allowable reflective surface deflection. The latter makes impossible to reach desired surface accuracy on Earth. The only way to prove the accuracy is calculation using measurements results. This paper addresses an investigation of reflective surface facet shape of large mesh reflector. Primary goal of investigation was to verify mathematical model of reflective surface using experimental data. Test mockup was developed to perform an experiment. The mockup consists of aluminum tube frame, two symmetrical cord nets, tensed on it and a stretched mesh. Cord net bounds the central facet being investigated and three peripheral facets as boundary constraints. Mathematical model is based on finite element method formulation. Cord and mesh tension is taken into account in model. Gravity is used as a loading condition. Series of calculation with variable model parameters was made to relate mesh tension and its surface density. Experimental and nu-merical results were compared via correlation of cord sagging and also surface RMS deviation from flat shape. Surface shape was analyzed using laser radar measurements data and numerical results. Measured for particular test conditions shape was compared to shape, calculated during numerical simulation in order to verify mathematical model. As a result of a performed analysis it was stated that difference between measured and numerical results is on an average 7% which can be considered as a prove of finite element model adequacy.

 

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