## 5 Conclusions  
By far, the greatest part of the vibrational energy was produced at lower frequencies. Therefore, in order to improve mechanical performance, an effort can be made to ensure that all the natural frequencies of the mount springs are as high as possible. In existing approaches, as the dimensions of the DASH interferometer increase, the natural frequency of the assembly can only be increased by increasing the adhesive area. As an example, a space-borne NIR DASH interferometer assembly's bonding surface was found to be detached during the vibration testing at the instrument level because of the lower natural frequency. Therefore, a large-sized interferometer cannot be stably mounted by improving natural frequency. In this study, by taking the mechanical stress of a flexible structure and shear stress at the bonding surface as the target, its dimensions and phase position could be optimized for an NIR DASH interferometer (as an example). Compared with the existing structure, the optical elements and flexures moved together during the vibration tests, and the maximum stress was located at the wing of the flexible structure. However, the maximum stress on the mechanical elements in the present structure was higher than that in the previous works, which was lower than the tensile strength of the material. The adhesive area and maximum shear stress at the bonding surface were decreased by adjusting natural frequencies of the assembly. In the proposed method, the mechanical material and adhesive area were optimally designed. Therefore, the thermal resistance of the assembly was improved by 7.5 times, which could help to minimize the impact of ambient temperature. The test results indicate that the DASH interferometer assembly was undamaged before and after the tests. The proposed design of flexible structures can be used in space-borne wind measurement instruments. Similarly, the approach presented can also be used to mount large-sized prisms.  
Moreover, the form of a flexible structure is not limited to one type of application, where it needs to be redesigned according to the vibration mode of the interferometer. As the spectral resolution increased, the dimension of the DASH interferometer increased, which caused the shape of the wing to change. The flexible structure at the bonding surface was no longer needed, which existed in the design of a short infrared wave DASH interferometer. Similarly, as the columns in the frame structure were also related to the vibration mode of the interferometer, the columns of other interferometers or prisms need to be redesigned.  
Conceptualization, J.S. and Y.F.; methodology, J.S. and W.W.; simulation, J.S. and C.C.; tests, J.S., X.H., and B.H.; data curation, D.F and J.L.; writing--original draft preparation, J.S. and D.F.; writing--review and editing, J.S.; funding acquisition, Y.F. and W.W. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the National Natural Science Foundation of China (41005019), the West Light Foundation of the Chinese Academy of Sciences (XAB 2016A07), and the West Light Cross-Disciplinary Innovation team of the Chinese Academy of Sciences (E1294301).  
Not applicable.  
Figure 15: Schematic of optical test before and after the tests: (**a**) schematic of optical test; (**b**) interference fringe; (**c**) fringe frequencies before and after the tests.