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Identifying Critical Design Variables and Domains for Design Optimization of Deployable Tape Springs for Controlled Deployment



The deployment speed of tape springs is a critical factor effecting the structural performance of aerospace components. At either extreme, an undesirable speed of deployment could result in (a) only partial deployment if too slow or (b) damage to the tape spring and/or removal of attached articles if too fast. While traditionally tape springs have been fabricated to maintain a uniform distribution of material and geometric properties, this study proposes that an optimal distribution of material and geometric properties can be used to achieve a desirable speed of deployment. This paper develops the foundation for the design optimization of a FlexLam carbon fiber tape spring for desired deployment speed. The deployment response of the tape spring was simulated using finite element (FE) analysis. A parametric study was performed to identify the critical design variables in the tape spring optimization problem with the objective of achieving a desirable speed of deployment. Both uniform and gradient changes in composite tape spring thickness, width, stiffness, density, and ply angle were investigated. Results show that uniform changes in thickness and ply angle, as well as gradient changes in tape spring width, have a considerable effect on the deployment speed. The critical range for the variable thickness was bounded between 0.05 mm and 0.5 mm. The critical range for the fiber orientation of the middle unidirectional ply was between 0° and 90°. The critical range for the gradient width ranged between 12.7 mm and 25.7 mm, specifically with the width increasing from the fixed end of the tape spring to the free end. The results from the parametric study pave the road to conducting an effective multi-objective topological design optimization of deployable tape springs.

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