Axisymmetric Optical Membrane Modeling Based on Experimental Results

The United States Air Force, Department of Defense and commercial industry have recognized the great value of near-earth space development, specifically in satellites for use in communications, ground and space surveillance and more active roles. However, resolution, or the primary optic s diameter, has been a limitation, especially for ground surveillance. Deployable optics has been investigated to allow larger optics in space and membrane optics has received increasing attention recently. The membrane's flexible nature requires some passive and possibly active control to reduce optical distortion caused by manufacturing, deployment, or other effects during use. Piezoelectric surface controllers are one option to actively control the membrane on the order of optical measurements (micron displacement or less). Multiple configurations of transverse displacements are feasible depending on the piezo zone locations and activation. The current thrust of industry is reducing the effort, time and cost of manufacturing and testing through use of computerized modeling and simulation; therefore, this was investigated for a membrane mirror and piezoelectric combination. Prior experiments using 6-inch diameter membranes have been conducted with an axisymmetric piezoelectric material layer on the non-optical surface. Various voltage differentials were applied to the piezo and the transverse displacement was measured. A finite element code, using perturbation techniques, was written in MATLAB and tested to check the feasibility of using computer models for the micro-displacements occurring with the membrane-piezo lay-up. The computer program considered was developed for axisymmetric conditions; however, in many cases, these conditions tended to dominate. Under these conditions, the finite element code produces results that represent the axisymmetrically reduced expeAir Force Inst of Tech Wright-Patterson AFB OH School of Engineering and Management is the author of 'Axisymmetric Optical Membrane Modeling Based on Experimental Results' with ISBN 9781423517023 and ISBN 1423517024.