PARAMETRIC STUDY OF NET-SHAPE MEMBRANE APERTURES *

The Air Force, as well as many other organizations, has considerable interest in developing deployable space-based parabolic membranes. This paper discusses the parametric study of near-net shape membrane apertures. A finite element model is used to evaluate the range of parameters (coating stress, membrane substrate stress/shrinkage, and boundary conditions) over which the linear theory applies. Two aperture diameters (1m and 152mm) are modeled for three different focal lengths (F # 2, 5, ∞ ) and two sets of boundary conditions (fixed outer boundary and pinned outer boundary) using ABAQUS. The diameters are based on the sample size currently being used for coating testing and the expected diameter of a larger scale test article planned at the Air Force Research Laboratory. Sensitivity studies are performed to evaluate the effect of coating non-uniformity using coating/film thickness variation and coating stress variation. A comparison of theoretical, linear, and nonlinear finite element results is presented.