Surface Shape Analysis of Mesh Antenna: By Combining Membrane Analysis and Cable Analysis

For multibeam satellite communication systems, large mesh reflector will be used. The surface of a mesh reflector can be regarded as a membrane structure, that experiences large deformation during surface forming. It is important to consider the characteristics which are unique to membrane structures; the shape of a mem-brane structure cannot be prescribed a priori because its shape, external loads on the membrane structure and the internal stresses interact in a nonlinear manner. In order to achieve an accurate design, nonlinear shape analysis that considers large deformation is indispensable. In developing an appropriate nonlinear analysis method, the structural characteristics of mesh and the analytical points described below must be taken into account. (1) A membrane is a tension stabilized structure. (2) A membrane can experience large deformation. (3) Initial whole shape cannot be described using only the size and combination of structural membrane parts. (4) A surface forming process must be involved in the analysis. (Initial membrane tension is determined only on the base plane.) This paper presents a nonlinear finite element analysis method for membranes using the total Lagrangian formulation with second order strain; the Green Lagrange strain. The Green Lagrange strain measure allows the effect of any rigid body motion to be removed entirely from the evaluation of strain. By combining CASA (CAble Structure Analyzer) and proposed membrane analysis method, the shape of mesh antenna surface supported by cable network can be analyzed. The effects of membrane tension, cable tension, focal length, and model scale on the surface shape were revealed from computational results.