Sensitivity Study of Precision Pressurized Membrane Reflector Deformations

Abstract

Geometric tolerances for precision reflectors are much more stringent than for traditional structures. This makes the reliability of their design critical whenever test verification is difficult, as in the case of space inflatable reflectors. However, the accuracy of pressurized film shape predictions can be degraded by many factors, which are often not sufficiently recognized. To show the importance of details in precision membrane analysis, the sensitivity of membrane shapes to selected environmental effects and physical assumptions used in numerical modeling is illustrated. In particular, 1) film thickness and material property variations, 2) thermal effects and support perturbations, and 3) the modeling of wrinkling are considered. Errors from inappropriately accounting for the preceding in the prediction of parabolic reflector shapes are compared to typical reflector tolerances. The main contribution of this study to the wealth of previous work on membrane structures is to demonstrate the practical importance of the preceding effects in current industrial practice. Another contribution is the development of a simple, high-precision, and robust numerical tool for axisymmetric membrane analysis.