直升机尾传动轴系的非线性刚度参数辨识方法

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

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 parameter identification method based on test data was proposed to evaluate the nonlinear stiffness of a tail drive shaft system.Firstly,modal testing on the tail drive shaft system under low-amplitude excitation was carried out,and a simplified dynamic model of the tail drive shaft system was established,which was verified by testing results.Then,the stepping sine sweep testing under different excitation levels was conducted,and the relationship between nat⁃ural frequency and displacement amplitude was obtained based on the measured frequency response function.Moreover,the finite element iterative calculation of the simplified model was carried out to achieve the relationship between the nat⁃ural frequency and the equivalent stiffness of the tail drive shaft system.Finally,the relationship between the equivalent stiffness and the displacement amplitude was established,and the nonlinear stiffness of the tail drive shaft system was identified.