The influence of adhesive bonding and curing on the accuracy of mirror surface shape was analyzed to realize low-stressassembly of large aperture mirror. Firstly, based on Hooke's law, a curing shrinkage stress equation was deduced, takingdeformation of the mirror and support structure into account under the boundary condition of continuous edge bond, andkey parameters effecting mirror deformation were obtained. Secondly, for a 514mm ULE spectrometer primary mirrorwith an inserts structure mosaiced and bonded on mirror-back, an equivalent linear expansion coefficient method wasused for finite element modeling. The shrinkage stress at the bond edge of mirror and the mirror surface shape wereanalyzed. It’s found that adhesive shrinkage has a significant effect on the mirror surface shape. Finally, the insertsstructure of mirror assembly was optimized. In contrast to the non-optimum structure, the average stress of adhesivesurface caused by adhesive curing shrinkage reduced from 0.28MPa to 0.18MPa, and the mirror surface shape (RootMean Square, RMS) reduced from 0.029λ to 0.017λ. Finite element analysis results of the mirror assembly were given atlast, surface shape accuracy (RMS) of mirror is 0.012λ under a load case of 1g gravity and 4°C temperature rise, and thefirst-order natural frequency of the component is 216 Hz. The obtained results showed that a suitable optimized supportstructure can effectively relieve adhesive curing stress, and also satisfy the design requirements for both the static anddynamic stiffness.
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