Fundamental Design of Tensioned Precision Deployable Space Structures Applied to an X-Band Phased Array

The tendency of a tensioned structure to self-align with the load direction may be harnessed to create a precision structure that has potentially greater passive stability, more deterministic dynamics, and simpler metrology requirements than those of the traditional truss structure. Structural sti↵ness is derived from the nonlinear geometric sti↵ening of the tensioned structure, rather than from the mechanics of materials. With the absence of structural depth, the traditional structural precision issues related to thermal deformations are reduced to two-dimensions, and metrology and shape control may be simplified into the load management and planarity control of discrete tensioning points. The objective of the presented research is to develop a fundamental understanding of the mechanics for tensioned precision structures, in terms of a potential first application as an X-band phased array radar. Approximate analytical relationships are developed to determine sensitivities and then used as e↵ective tools for ecient system design. The e↵ect of boundary conditions on internal components of a non-uniform tensioned structure is investigated and discussed, as well as, strategies for passive error correction and the balancing of built-in stochastic error by tuned compliance. Designing for the e↵ects of thermal warping and tension pull-out of deformation are also discussed. The observed relationships are validated against a parametric finite element model of the proposed X-band phased array design.