Experimental Evaluation of Reducing Cable-Strain Energy of Tension-Truss Surface with Compression Members

Abstract

Cable network used to form the parabolic surface of an antenna can be designed to reduce its weight. However, the strain energy in the cable increases with an increase in the number of cables. This is because the aperture diameter and surface accuracy increase. Accordingly, to maintain a precise surface, the support structure must be enhanced by increasing its rigidity. Therefore, a surface-design method is introduced wherein several compression members, instead of tensile cables, are inserted into the support structure to reduce the total strain energy. Nevertheless, it is difficult to achieve the required surface accuracy when the manufacturing error (i.e., cable-length error) is considered during cable fabrication. In this study, an experimental evaluation is conducted to determine the admissible cable-length error with respect to constructing a precise surface. Results suggest that controlling the average bias error of the cable length is vital in obtaining a precise surface. Additionally, the strain energies of the rod-and-cable web and cable web are compared; results demonstrate that the strain energy in the former can be reduced when the cable-length error is considered during the manufacturing process.