测试真空中薄膜阵面自振特性的等代方法

An equivalent approach for testing natural vibration characteristics of a planar film reflect-array in vacuum

大气环境下,空气产生的附加质量会大大折减薄膜阵面的刚度,致使薄膜阵面的自振特性与在实际真空工作环境中存在较大误差。基于针对真空中薄膜阵面动力特性进行试验验证,而开展真空测试试验仍然存在困难的实际情况,为忽略空气附加质量的影响,提出以大气环境下的网格膜等代真空中薄膜测试自振特性的方法。通过对比两者振动特性数值分析结果以及采用双轴张拉装置和非接触式位移动态采集设备进行试验验证,研究得到以大气环境下网格膜自振频率等代真空中阵面膜频率的结论公式。

In atmospheric environment, the additional mass produced by air greatly can reduce the stiffness of a planar film reflect-array to make its natural vibration characteristics have a larger error compared with those in actual vacuum environment. In order to test and verify dynamic characteristics of a planar film reflect-array, considering practical tests in vacuum environment being unmanageable and uneconomical, an equivalent approach to measure a grid film’s natural vibration characteristics in atmospheric environment neglecting the effect of additional mass produced by air to substitute those of a planar film reflect-array in vacuum environment was proposed. The numerical simulation results for natural vibration characteristics of both cases were contrastively analyzed, and the test verification was conducted using biaxial tension device and non-contact displacement dynamic collection equipment. Finally, a useful formula was obtained to calculate the equivalent natural frequencies of a planar film reflect-array in vacuum environment using the corresponding test values of a grid film in atmosphere environment.