Fig. 1. Structures of mirror and bonded joint. (a) 100 mm-diameter mirror; (b) invar bonded joint

Fig. 2. Free shrinkage model of adhesive layer

Fig. 3. Deformation diagram of bonded joint

Fig. 4. Generalized Maxwell model

Fig. 5. Stress varying with time

Fig. 6. Finite element model of bonded mirror assembly. (a) Finite element model of mirror assembly; (b) mesh details of adhesive layers

Fig. 7. Iterative curve of adhesive layer topology optimization

Fig. 8. Topology optimization results of adhesive layer. (a) Topology optimization result; (b) finite element model of adhesive layer

Fig. 9. Trends in mirror surface RMS and fundamental frequency. (a) Effect of adhesive area on surface RMS; (b) effect of adhesive area on assembly fandenmental frequency

Fig. 10. Adhesive layer shrinkage stress contours. (a) Before optimization; (b) after optimization

Fig. 11. History of adhesive layer stress development before optimization

Fig. 12. History of adhesive layer stress development after optimization

Fig. 13. Simulated contours of mirror deformation after adhesive curing. (a) Before optimization; (b) after optimization

Fig. 14. Mirror bonding test process

Fig. 15. Test scheme for in-situ dynamic surface shape monitoring during mirror bonding and curing. (a) Optical test path; (b) physical photo of test platform

Fig. 16. Initial mirror surface accuracy. (a) Surface shape test values; (b) mirror surface interference fringes

Fig. 17. Comparison of tested and simulated surface accuracy changes. (a) PV before structural optimization; (b) RMS before structural optimization; (c) PV after structural optimization; (d) RMS after structural optimization

Fig. 18. Interferometry surface shape test results for cured mirror surface. (a) Before optimization; (b) after optimization