WST, the Wide-field Spectroscopic Telescope: Telescope structure FE analyses

Abstract: The Altitude Structure of the Wide-field Spectroscopic Telescope (WST) is designed to support and position both primary and secondary mirrors, made of structural steel. Due to its dimensions, the Altitude Structure is a substantial part of the WST facility, and its weight, performance, and dynamic behavior play a critical role in the functioning of the Telescope. This paper discusses the iterative process starting from the preliminary structural layout and leading to the optimization of the entire Structure. A Finite Element (FE) model was developed, defining the detailed dimensions and cross sections of each assembly's beams and plates under representative boundary conditions, in order to correctly simulate the operational environment. This model enables accurate estimation of structural weight, mechanical deformations, and stresses, as well as its frequency response for the evaluation of both local and global resonance modes. Based on the initial results obtained using preliminary beam cross sections and shell thickness, several assumptions were formulated to drive the mechanical optimization of the Altitude Structure. The outcome of this work consists of a refined structural configuration and the formulation of the governing design criteria.