The Analysis Of Optical System Dimension Stability Based On Thermal-Structure Coupled Theory

This paper expounds the importance of thermal design for space optical system by means of the integrated Thermal Structure Optical method refer to the research of dimension stability for a large space optical system, It also has some guiding significance for engineering design. It introduces the background for the research of the optical system and the present apply condition of Thermal Structure Optical method. The method contains the Thermal-Structure coupled theory and the integrated Thermal Optical theory.In this paper, the model of optical system for a space has been changed to the simple form and the character of the model has been picked up. The finite element model of optical system included the thermal calculation model and the structure calculation model is built by using the ANSYS software based on the Thermal-Structure coupled theory. Calculation of the temperature and the thermal deformation of the optical system and its part is performed; The result of the calculation by ANSYS software has been picked up in order to getting the output file of the displacement. The ZERNIKE Polynomial has been using in the fitting processes which aimed at the thermal grads calculation; the thermal deformation data of mirror is fitted by non-spherical surface equations. It can provide initial conditions for further optical analysis, factors that different thermal environment influences curvature radius r of the quadratic surface equations is analyzed. Then a finite element model is built independently according to the equation of the primary mirror. Thermal deformation is calculated with 20 different three points restrict displacements. Discipline that different restrict displacement influences thermal displacement is received. The slightest and the most serious restrict displacement to the surface thermal deformation is obtained. All those can provide consultations for the optical system's thermal control.The integrated Thermal Structure Optical method is wildly used in the space filed, but it doesn't have been deeply launched at home because of the technique and the equipment. The paper has been given an attempt and settled basis for its theory research and practical application.