关键词: 飞机地面振动, 频率响应, 模态分析, 系统识别

Abstract:

A frequency domain Muilti-Input/Multi-Output （MIMO） Modal Identification method is presented in this paper. Its accuracy, reliability and capability of handling closely-spaced or repeated modes are proved by computer simulation and real structure testing. The application in aircraft Ground Vibration Test （GVT） of a modern fighter is given. The results show that compared to traditional multipoint sine dwell GVT technique, the test operation is easier, the period is shorter and the accuracy is higher, compared to the time domain MIMO identification methods developed in 1980's, the order of the tested system （e. i. the number of modes） can be determined directly. Therefore, the computation is reduced, and the necessity of distinguishing structural and"noise"modes is avoided.

Key words: aircraft grourd vibration, frequency response, modal analysis, system identification