Research On Structure And Stability Of Arrayed Final Optics Assembly

Inertial Confinement Fusion(ICF)is one of the important approaches to solve energy shortage problems.The Final Optic Assembly(FOA),as one of the core units in the ICF facility,functions for laser focusing and precise positioning.FOAs mainly have two types: single beam type and array type.At present,single beam FOA has been realized in China,but array type has not.In order to provide reference and basis for the final structural design,this thesis is to conduct a pre-research on the array-type FOA,mainly including structural design,static/dynamic performance analysis of key components.Based on the overall functions and technical requirements of the arrayed FOA.The main contents of this thesis are as follows:(1)Starting from the requirements of aiming accuracy,the effects of position and angle errors of the optical elements in the FOA on the target accuracy are analyzed,and corresponding technical solutions are proposed according to the accuracy specifications.The array-type FOA adopt a onedimensional off-axis 2 × 2 focusing scheme,the author determines the relative position of each optical element according to the focusing method,design the supporting structure of each optical element through a modular design method,and finally designs the focus-adjusting mechanism with high-precision adjustment functions in multiple directions.(2)An FEM simulation model is established for the designed structure of arrayed FOA.The structure of the array FOA is analyzed,the key points of establishing the finite element model are found out,and then modeling analysis and experimental verification on the key points of modeling are performed separately.The three key points considered are: the bolt connection model,the Zdirection movement unit of the focusing mechanism,and the leveling mechanism.The accuracy of the bolted connection model and the leveling mechanism model was verified by the modal experiments.Aiming at the FEM of the Z-direction moving unit of the focusing mechanism,an approach combining a simplified model analysis method and a modal experiment method is used for verification.The results of FEM are compared with the results of simplified model analysis and experimental data to verify the accuracy of the model establishment.(3)As the core part of FOA,modeling and stability analysis of the focusing mechanism module are completed.In the static analysis,the author uses the FEM and simplified model analysis method to calculate the deformation and inclination of each point of the guide rail at different positions of the focusing mechanism,and calculates the aiming error based on the influence of the guide rail deformation.A straightness test is performed on the focusing mechanism.Comparing the test results with the theoretical calculation ones,the credibility of the simplified model and the FEM in calculating the pose error of the target lens are confirmed.Dynamic stability analysis is mainly modal analysis.Modal feature extraction is performed on the plane of the target lens by a threedimensional scanning laser vibrometer.Experimental results verify the accuracy of the modal analysis results.(4)Stability analysis of the entire array-type FOA,including static analysis,modal analysis,and harmonic response analysis are performed.In the static analysis,the author obtains the overall deformation of the arrayed FOA,which provides an important reference for structural design and optimization.In modal analysis and harmonious response analysis,the author obtains the first six natural frequencies and mode shapes,and analyzes the vibration form of each mode and the causes of the mode shapes,which provides important modal parameters and vibration characteristics for ICF facilities.The natural frequencies calculated by the modal analysis are compared with the environmental vibration frequencies,showing that the peak frequencies are far away from the environment frequencies.