A feasibility study has been conducted to evaluate the performance of composite materials for the elevation structure of EST.
Render of the upper part of the Elevation Structure of EST.
The structure of the EST telescope has already been defined at the preliminary design level. The structure is made of steel and complies with requirements.
To improve the design and perform a materials trade-off, we have studied the feasibility of implementing a carbon fibre reinforced polymer (CFRP) design for the upper part of the Elevation Structure, in order to reduce the mass and to keep the stiffness, thus increasing the system's eigenfrequencies to have a higher bandwidth for the control of the main axes of the telescope.
This study has been carried out by the company ESTEYCO in collaboration with the FIDAMC foundation, developing a manufacturing strategy for the Elevation Structure that minimises the composite manufacturing costs.
In order to develop this study, the number and disposition of laminates for each part has been optimised and a direct comparison with the stiffness of the baseline steel design has been performed. Therefore, independent finite element models have been developed for the Elevation Structure to analyse eigenfrequencies and the image motion of this alternative design. Finally, a cost budget has been estimated.
The conclusions of this study could be summarised as an improvement of the CFRP Telescope Structure performance mainly in eigenfrequencies and image motion. However, this slight improvement does not justify the composite manufacturing cost.