There is a growing need to build telescopes and structures for the observation of exoplanets, main-belt asteroids, and NEOs. Space observation capabilities can be significantly enhanced by large aperture structures. Structures that span several meters could potentially revolutionize observation technologies. These include star apertures for imaging distant objects such as exoplanets and high-resolution, high-aperture telescopes. In addition to size, such structures require controllable precision surfaces and high packing levels. A promising approach to achieve high densification for large surfaces is the incorporation of compliant materials or gossamer. Gossamer structures alone do not meet the stiffness requirements for controlled use. Supportive stiffening mechanisms are needed to fully exploit their structural potential. The accuracy of the "active" surface constructed from a Gossamer also depends on the supporting structure it carries. This article examines structural assemblies consisting of modular inflatable diaphragms that are pneumatically inflated with inflation gas. These composite composites can provide desirable properties.
They show the design of large assemblies of these modular elements. The work focuses on separate assembly strategies that are optimized for two broad applications. The first class of structures requires efficient loading and distribution. Such structures do not require high-precision surfaces, but the ability to transfer large loads efficiently and reliably. This can be achieved by a hierarchical arrangement of inflatable units. As a collective assembly, they must also be stiffer than their constituent modules.
The preferred placement of different modular units leads to local stiffness modulation. This in turn helps to change the load transfer characteristics. Applications of such structure also extend to extendable towers or air lift aircraft for maneuvering in the atmosphere. The second are structures with precision surfaces for optical imaging and high gain communication ports. They show excessively limited modular assemblies with elastic averaging when mounted with a very large number of modules. The averaging effects are enhanced as the number of subunits approaches the required surface accuracy with a sufficiently large number. Her work includes basic structural studies to develop possible sizing techniques for both classes of structures. A structural analysis strategy with discrete finite elements was developed to simulate the assembled behavior of modular units. The structural model of each inflatable unit has been extended from the previous work to approximate each unit as a 3-dimensional truss system. The analysis results are compared with simulations of the commercial analysis package LS-Dyna. The analysis leads to an understanding of the extent to which inflatable boats can be effectively enlarged. Critical geometric design considerations are identified for the state of stowage and deployment of each structure. Their proposed construction of compliant hinges between structure to assemble even large units. Further work includes the development of prototypes and the measurement of the task force for the validation of the structural model.
(H / T Adam Crowl)
[1812.11667] Modular Inflatable Composites for Space Telescopes January 2, 2019
By Brian Wang, Nextbigfuture.com