Research On Optical And Mechanical Structure Design And Mechanical Characteristics Of Space Telescope

With the remarkable achievements of Jilin-1 satellite,Tianwen-1 Mars probe and Chang’e-5 moon sampling,my country has gradually accelerated its transformation from a space power to a space power.After years of intensive cultivation in the field of space earth observation,a series of remarkable results have been achieved and many core technologies have been mastered.In order to further strengthen the observation and exploration of the universe,it is necessary to continuously develop the design of space telescopes and related key technologies.This paper applies the method of combining theory with traditional experience,and uses finite element analysis technology to design and analyze the primary and secondary mirror components and primary support structure of a space telescope.The mechanical and thermophysical properties of commonly used mirrors and optomechanical structural materials are compared and analyzed,and their performance indicators are comprehensively evaluated.Among them,Si C materials are selected for the production of light-weight mirrors,and carbon fiber composite materials are used as the main supporting structure of the telescope.Preliminary design of the primary mirror and secondary mirror structure is carried out by using the method of combining empirical design and finite element analysis.The structure parameters of the primary mirror with a diameter of 1130 mm are designed,the thickness of the lens body is 95 mm,and the back three-point support scheme is adopted;the secondary mirror with a diameter of 300 mm adopts the back single-point support scheme,and the thickness of the lens body is 38 mm.The lightweight technology research is carried out for the primary mirror and secondary mirror.Drawing lessons from the existing lightweight design methods of mirrors,traditional experience design,topology optimization design based on traditional experience design,and direct topology optimization design are carried out on the main mirror structure.Comparing the three lightweight primary mirror structures,it is found that the mirror designed based on traditional experience has reasonable structure,uniform material distribution,which has advantages in thermal environments,but there is still room for further optimization.The mirror takes into account the advantages of traditional experience and topology optimization,but also reduces some performance.Compared with the optimization before the optimization,the primary mirror reduces the mass and reduces the deformation of its own weight;the primary mirror obtained by direct topology optimization has the highest light weight rate,but also reflects the smallest deformation under its own weight.The topology optimization design method is used to design the lightweight structure of the 300 mm aperture secondary mirror,and the topological optimization secondary mirror weighs only 1.83 kg.The structure design of the main supporting structure to ensure the precise position of the spatial optical system is carried out.The tube structure and the truss support structure were compared and analyzed,and the truss structure was finally selected as the main support structure of the space telescope.The key factors affecting the stiffness of the truss structure are studied,and the position relationship of the truss rods when the stiffness is the best is optimized by using the Opti Struct software.Basis On this,the truss rods in different positions are grouped and optimized,and finally the optimized design has a high stiffness and light weight.The main support structure of a truss-type space telescope with stable quality.The finite element model of the entire space telescope was established,and the static,dynamic and thermal structure characteristics of the entire space telescope were analyzed using the finite element analysis method.When the optical axis is horizontal,the surface shape of each reflector meets the design index requirement of RMS less than 12.6 nm under the self-weight working condition and the uniform temperature rise working condition of 5℃;the constrained modal analysis result of the whole machine shows that the fundamental frequency is 99 Hz.The dynamic stiffness of the telescope is high enough;the analysis results of sinusoidal vibration and random vibration also verify that the space telescope structure designed in this paper can withstand dynamic environment during launch.