Anders Sjöström

An Integrated Model of the European Extremely Large Telescope

Integrated models including optics, structures, control systems, and disturbances are important design tools for Extremely Large Telescopes (ELTs). An integrated model has been formulated for the European ELT and it includes telescope structure, main servos, primary mirror segment control system, wind, optics, wavefront sensors, deformable mirror, and an AO reconstructor and controller. There are three model phases: Initialization, execution of a solver to determine time responses, and post-processing. In near future, the model will be applied for performance studies and design trade-offs for the European ELT.

Modeling acoustic properties of different types of lightweight T-junctions

To accurately model the effect on the dynamic behavior of a floor when using glue in the joints between the chipboards and beams in a lightweight structure can be a daunting task. It is however important to have a model that can simulate these junctions with high fidelity. The behavior of T-junctions with different geometries and methods of adhesion has been previously investigated via measurements [1]. This investigation builds on that work and aims at developing an accurate finite element model of the junctions. The previously investigated junctions were made of chipboards fixed to a spruce beam using screws or a combination of screws and glue. The boards were either a single plate or two plates meeting each other on top of the beam. In this investigation different approaches of simulating the junction using the finite element method were tried. The validity of the FE models was evaluated by calibrating them with previous performed measurements in [1]. A parameter study was also performed on the models to investigate the effect of the glue on the overall performance of the structure. (Less)