| The space mirror will face many extreme shock loads in harsh launch and space environments.It has been found that the shock loads in the space mirror structure are generated by various devices.For sensitive space structures,such as flexible supports in optical elements and mirror components,these high-intensity shocks are a major concern.The structural design of the mirror component is related to the imaging quality of the entire optical system.To ensure the normal operation of the space mirror during the launch and space environment,as a core system,it must have good surface shape accuracy and excellent structural stiffness.In this paper,a Φ150mm aperture mirror component is studied,and shock simulation analysis and parameter optimization of the mirror component are carried out to ensure the surface shape accuracy of the mirror while reducing the shock stress of the mirror component under shock loads,thus improving the anti-shock capability of the mirror component.The specific research content is as follows:(1)Comparative analysis of the performance of commonly used materials for mirror components,combined with the requirements of the actual working environment,selected Zerodur as the material for the mirror,and 4J32 as the material for the flexible support structure of the mirror.The commonly used mirror support forms are discussed,and a peripheral support mirror component structure scheme is designed.The surface shape accuracy of the mirror component is examined under 1g gravity load and 5℃ uniform temperature rise load conditions.The structural parameters of the flexible support structure are optimized using the orthogonal optimization experimental method.(2)A finite element simulation analysis method is studied to investigate the response of the mirror component under impact excitation.The impact response spectrum is used as the analysis method to simulate the support structure.The synthetic wavelet method is used to convert the impact response spectrum into a time-domain waveform,which is then used as input to perform impact simulation analysis on the mirror component using finite element analysis software.Based on the improved recursive numerical filtering method,the impact response spectrum is calculated and compared with the standardized impact response spectrum to verify that the mirror component’s impact stress response is 153 MPa,which is higher than the stress value under the safety margin.To meet the design target requirements,sensitivity analysis of the dimension parameters of the flexible support structure is performed,and a response surface is established to determine the dimension parameters of the flexible support structure based on the optimized candidate points.The impact stress of the optimized flexible support structure under impact load is 131 MPa,which is 14.4% lower than that of the initial structure scheme.The fundamental frequency of the optimized mirror component is 406 Hz,which is 35% higher than that of the initial structure scheme.(3)The finite element method is used to simulate the surface shape accuracy of the mirror component under 1g gravity load and 5℃ uniform temperature change load.The dynamic characteristics of the mirror component under low-frequency sinusoidal excitation and random vibration load excitation are analyzed.The analysis results show that the surface shape RMS of the mirror component under 1g self-weight load is 10.6nm,and under 5℃uniform temperature rise load is 2.2nm.The maximum stresses of the mirror component under low-frequency sinusoidal excitation and random vibration excitation are 10.1MPa and58.2MPa.It is verified that the mirror component has sufficiently high static and dynamic stiffness and thermal stability.The results show that PV=0.083λ,RMS=0.019λ(λ=632.8nm),which meet the requirements of the index. |
