某型飞机主要机体结构模态分析及测试

Modal Analysis and Test of the Main Structure of an Aircraft

基于LMS纯模态试验测试系统对飞机进行地面共振试验,得到主要机体结构各阶模态参数,依据试验结果对有限元模型进行修正。修正后各阶模态频率的计算结果与地面共振试验值的误差均小于4%,最终得到的准确动力学模型可用于飞机首飞前颤振特性分析。这种有限元计算与模态试验相结合的动力学分析方法,有助于提升试验效率和提高计算分析的准确性。

The ground vibration test of an aircraft was implemented based on the LMS MIMO normal test system,and the modal parameters of the main structure of the aircraft were measured.The results were applied to modify the finite element model.Then,the computation result of each modal frequency of the modified finite element model was compared with that of the ground vibration test.It was found that the maximum difference between the calculated modal frequency and the measured modal frequency was less than 4%.Finally,the accurate dynamic model was obtained.This dynamic model can be used in flutter analysis of the aircraft before the first flight.This analysis method of combining the finite element calculation with the modal test is conducive to raise the efficiency of test and the accuracy of finite element analysis.