摘要
根据线性结构中白噪声响应之间的相关函数与脉冲响应函数具有相同的数学表达式的特点 ,用模态分解法把相关函数分解为不同频率的信号 ,然后把各个不同频率的信号看作单自由度系统脉冲响应进行模态参数辨识 .该方法的最大优点是 :(1 )把多自由度系统的模态参数辨识问题转变为单自由度系统的模态参数辨识问题 ;(2 )不存在模型阶数的选取问题 ;(3 )对输出噪声具有鲁棒性 ;(4)从测试数据中直接识别实模态 ,避免了由复模态提取实模态问题 ;(5 )仅根据一个测点的响应信号就可辨识结构的频率和阻尼 .算例表明 ,用模态分解法辨识线性结构在环境激励下的模态参数是成功的 .
According to ambient excitation characteristics and the cross-correlation function between the responses of linear structures that is a sum of decaying sinusoids of the same form as the impulse response function of the original system, the cross-correlation function was decomposed into mode functions that are different frequency signals by using mode decomposition. The modal parameters identification techniques of single degree of freedom system were applied to each mode function to obtain the natural frequencies, damping ratios and mode shapes. There are many advantages of the method: (1) The problems of modal parameters identification of multi degree of freedom system for the linear structures undergoing ambient excitation are changed to the problems of single degree of freedom system; (2) There is no problem of electing the number of orders for mode; (3) The method is robust to the measurement noise; (4) Normal modes are identified from measured data without computation of normal modes from identified complex modes; (5) Parameters of frequencies and damping ratios are computed from data in one point of measurement. The simulations demonstrate that the method is effective.
出处
《上海交通大学学报》
EI
CAS
CSCD
北大核心
2001年第12期1761-1765,共5页
Journal of Shanghai Jiaotong University
基金
国家自然科学基金资助项目 ( 19972 0 16 )
关键词
数据处理
环境激励
模态分析
参数辨识
模态分解法
线性结构
模态参数
Damping
Identification (control systems)
Modal analysis
Natural frequencies
Robustness (control systems)
White noise
