Colloquia

Summary

In this thesis the deployment of a flexible compact array was studied with nonlinear finite element analysis. The flexible compact array is a solar array, which consist out of a mast and two blanket stacks with solar cells. The blanket stacks are folded in a zig-zag pattern and fold open when the mast extends. The components of the FCA were evaluated and representable simplified models were made. A special emphasis was put on the blanket segment, as this component contains many subparts and is very flexible. The dynamic behavior of the blanket, following from the deployment, is studied, and it was proven to be sensitive to initial conditions. Due to the long wall time involved for nonlinear transient analysis the full problem with 40 blankets could not be solved, but trends were evaluated to predict the behavior with 40 blankets. A mechanism is proposed to aid in the predictability of the deployment path, which is based on a constant force guiding cable on both sides on the blanket segments. This mechanism increased the predictability of the deployment of the blanket stack compared to the unregulated deployment. With a pretension of 0.01N for 7 blanket segments the maximum out of plane displacement is reduced from 0.234 m to 0.015m. An optimum of 2N was found to reduce the amount of contact between the blanket segments, for a study of 7 blanket segments. The stress-stiffening effects were evaluated for a 7-segment blanket stack with and without a guiding cable. Despite that the out of plane deformation of the blanket segment significantly decreased with a deployment mechanism, the strains in the model remained dominated by membrane stiffness. This shows the need for a nonlinear analysis to obtain the stress and strains during deployment. Finally, a test setup was modelled which allowed the out of plane deformations of one blanket segment and local deformations to be well represented. Multiple gravity compensation mechanisms were evaluated, and a study was performed to assess the different behavior on earth compared to space. Due to the extra mass of the gravity compensation mechanism both the unregulated and guided deployment did not follow the expected deployment path. However, the chaotic movement path and the influence of a deployment mechanism can be confirmed from a test and the deployment is not hindered by the gravity compensation mechanism.