Methods of Analyzing Surface Accuracy of Large Antenna Structures due to Manufacturing Tolerances

The manufacturing of a large deployable antenna structure for space application with high surface accuracy requirements has been the subject of many studies. This paper presents different methods of predicting the influence of manufacturing imperfections on the surface accuracy of the antenna. The direct method, based on Monte Carlo simulation takes into account the random distribution of manufacturing tolerances of the antenna structure individual members. In this method many versions of the same structure with different member length errors are created and analyzed for surface accuracy using the finite element method. The results are then evaluated to generate the manufacturing requirements needed for a specified surface. The Inverse Frequency Squared Method, an indirect method, uses the structural natural frequencies to estimate the surface accuracy due to random errors of the individual members. In addition the sensitivity of the surface distortion to individual member error is computed using a direct method and an indirect method based on the normal mode technique.