Computational seismic analysis of optical instrument structures: Computational analysis of seismic response of wide-field optical spectrograph structures in large telescopes

WFOS (Wide-Field Optical Spectrograph) is a first light instrument mounted on the Nasmyth focus of the TMT (Thirty Meter Telescope). The transient analysis was performed under infrequent earthquakes to study the WFOS shell structure's transient response using Abaqus software. Computer-aided design models of WFOS shell structure were established using Invar (4J32), a nickel-iron alloy, as the selected structural material. Time history analysis was performed on the WFOS structure under seven different earthquake time histories, and the structural responses of displacement, stress, and acceleration were investigated. the peak acceleration is reached when the support structure is dealt against seven infrequent earthquakes in three directions. This research's methodology and outcomes provide a guidance approach to seismic response analysis of the telescope components. A detailed briefing of the computer-aided design model and results are presented.