He jishu (Jun 2022)
Elliptic mirror finite element analysis of double drive compensated bending
Abstract
BackgroundIn order to meet the technical requirements of synchrotron radiation beamlines for related optical components, a double-drive four-point roller bending mechanism is designed.PurposeThis study aims to implement an unequal moment elliptical cylinder bending of high-precision large-size optical mirror through finite element analysis (FEA) simulation.MethodsFirst of all, a reflector with an external dimension of 1 200 mm×70 mm×50 mm was taken as the research object. Based on the object distance of 26.5 m, the image distance of 13 m and the grazing incidence angle of 2.8 mrad, the pressure applied to the bending moment was calculated according to the theoretical ellipse shape equation and the beam deformation bending moment equation. Then, the FEA software was employed to simulate and analyze the double-drive four-point bending mechanism. The focusing mirror was subjected to single-point compensation, double-point compensation, three-point compensation and four-point compensation in the presence of gravity compensation torque. Finally, the simulation compensation surface results obtained by FEA were compared with the theoretical calculation results.ResultsThe simulated application of unequal torque at both ends reduces the surface shape error from 0.81 µrad under single-point compensation to 0.075 µrad under four-point compensation, reducing 95.96% of the original error to the greatest extent. It can effectively reduce the elliptical bending surface shape error with theoretical value of 0.013 µrad, and the decreasing trend is gradually gentle.ConclusionsThis study indicates that the double drive compensated bending mechanism is feasible and effective to improve the bending accuracy of large-scale elliptical mirrors under multi-point compensation, and has important theoretical guiding role and significance for the bending technology of synchrotron radiation beamlines.
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