模态相关性分析和模型修正技术在反射镜仿真中的应用

Application of Modal Correlation Analysis and Model Modification to Reflective Mirror's FEM Simulation

胶的弹性模量和泊松比对反射镜光机仿真结果有重要影响,但参数受多种因素影响难以准确获得。通过测试得到反射镜的试验模态,根据文献[1]中胶的参数进行有限元仿真得到仿真模态,经相关性分析发现仿真模态和试验模态相关性差;随后以胶的弹性模量和泊松比作为设计变量,经SQP优化迭代得到胶参数,模型修正后的仿真模态和试验模态相关性显著提高;最后分析对比了模型修正前后反射镜在安装应力和低温环境两种工况条件下的面型和应力,计算结果显示,模型修正后安装应力的面型变化对光学成像造成影响,低温应力问题不容忽视。

The bond’s elastic modulus and Poisson’s ratio have important effects on optical-mechanical simulation of the reflective mirror,but these parameters are influenced by too many factors to accurately obtain.An experiment is conducted to obtain the test mode of the reflective mirror,a finite element simulation is conducted according to the bond’s parameters in the Literature[1] to get FEM mode,and then a correlation analysis is conducted to find that the test mode has a poor correlation with FEM mode.Subsequently,the bond’s elastic modulus and Poisson’s ratio are taken as variables,and an SQP iterative optimization is implemented to obtain these parameters.After model modification,the correlation between the modified FEM Mode and the test mode is significantly improved.Finally,the surface figure and stress of the reflective mirror under two working conditions of assembly stress and low-temperature environment after model modification is compared with that before the modification.The calculation results show that,after model modification,the change of surface figure resulted from assembly stress will have influence on optical imaging,and the problem of stress under low temperature can’t be ignored.