IDL Thermo-Mechanical Analysis Software (ITMAS)
The IDL Thermo-Mechanical Analysis Software (ITMAS) is a tool for dimensioning like CIRCE instruments. It presents some versatility. The user can introduce the number of optical and mechanical elements on the bench; the size and mechanical parameters of the bench and cane structures, the size and parameters of the thermal and vacuum shields. The software also includes thermal heating by electronics and radiation from the front of the telescope. Other useful options of the software include optimization of the thicknesses for minimum bending and thermal exchange, plot of results and prediction of the tilt of the image with time during observations. Limitations of the software are the shape of the beam that is used to calculate the bending and the number and order of shields. However, we expect to complement with other type of structures in future works. While the first use of this software is the optimization of CIRCE design, the ultimate goal of this software is to provide with a tool for other instrument builders. As an example, the software will be able to import elements from the AUTOCAD design automatically and calculate the thermal and mechanical restrictions. Other improvements include tolerance analysis results in ZEMAX.
The software has been used with simple examples in order to test its reliability. Results as volume, areas, and moment of inertia were verified with analytical calculations as well as the online calculator at http://www.mecatools.free.fr/generale/mtorsion.html. Results of flexures (bending, shear and moments) for simple cases as distributed loads and single concentrated loads at various positions agree with analytical solutions and with the online calculator http://www.efunda.com/formulae/solid_mechanics/beams/casestudy_bc_cantilever.cfm.