直升机尾传动轴系的非线性刚度参数辨识方法

提出了基于测试数据来识别尾传动轴系非线性刚度参数的方法。首先,对尾传动轴系进行低幅值激励下的模态测试,并建立尾传动轴系的简化模型,与试验结果对比验证模型的准确性。然后,对尾传动轴系开展不同激励水平下的步进正弦扫频测试,基于测试频响函数得到固有频率随位移幅值的变化关系。对建立的尾传动轴系简化模型进行有限元迭代计算,可以识别出固有频率随等效刚度的变化关系。最终建立起尾传动轴系等效刚度与位移幅值的关系,识别出尾传动轴系的非线性刚度参数。

A METHOD FOR IDENTIFYING NONLINEAR STIFFNESS OF HELICOPTER TAIL DRIVE SHAFT SYSTEM

A method based on test data to identify the nonlinear stiffness parameters of the tail drive shafting is proposed. Firstly, the modal test under the low amplitude excitation is carried out on the tail drive shaft system, and a simplified model of the tail drive shaft system is established, and verify the accuracy of the model by comparing with the test results. Then, the stepping sine sweep test under different excitation levels is carried out on the tail drive shaft system, and the relationship between the natural frequency and the displacement amplitude is obtained based on the test frequency response function. The finite element iterative calculation of the established simplified model of the tail drive shaft system can identify the relationship between the natural frequency and the equivalent stiffness. Finally, the relationship between the equivalent stiffness of the tail drive shaft and the displacement amplitude is established, and the nonlinear stiffness parameters of the tail drive shaft system are identified.