【作者】 李中付； 华宏星； 宋汉文； 傅志方；

【Author】 LI Zhong-fu, HUA Hong-xing, SONG Han-wen, FU Zhi-fang( Particular Environment 4 Preserve Division, Naval Medical Research Institute, Shanghai 200433 State Key Lab of Vibration Shock & Noise, Shanghai Jiao Tong University, Shanghai 200030 Department of Mechanics & Engineering Science, Fudan University, Shanghai 200433)

【机构】 海军医学研究所海军特殊环境与防护研究室； 上海交通大学振动冲击噪声国家重点实验室； 复旦大学力学与工程科学系；

【摘要】 假定任意随机激励信号由白噪声与非白噪声信号组成,由此导出线性结构响应之间的相关函数由两部分组成,一部分与脉冲响应具有相同的数学形式,另一部分为其它形式,利用模态分解法的基本原理,把相关函数分解为各个模态函数的叠加与余项之和。这样,第一部分信号已经分解为不同的模态函数,第二部分中的周期信号也变成了模态函数。这就把非稳态环境激励下多自由度线性结构系统的模态参数辨识问题转化为类似于已知各个单自由度系统的脉冲响应进行参数辨识问题。理论和模拟实验及斜拉桥模型参数辨识实例表明,本文成功地利用模态分解法进行非稳态环境激励下多自由度线性结构系统的模态参数辨识。其主要优点:一是无论是白噪声激励、稳态随机激励还是非稳态随机激励,仅根据结构的响应辨识线性结构的模态参数;二是能有效地识别出环境激励中的周期成分。更多还原

【Abstract】 It was assumed that random signals consist of white signal and non-white signal. Non-white coefficient was brought forward. The cross-correlation functions between responses of linear structures undergoing non-stationary random signals consist of two parts and one is a sum of decaying sinusoids of the same form as the impulse response function of the original system. The cross-correlation functions were decomposed into mode functions plus the residue. Modal parameters identification technique of single degree of freedom (DOF) was applied to each mode function to obtain the natural frequencies, damping ratios and mode shapes. Numerical simulations for a linear system with four DOF and identifying modal parameters of cable-stayed bridge undergoing ambient excitation demonstrated that the method is effective in identifying parameters of linear structures undergoing non-stationary ambient excitation using mode decomposition. There are two advantages in the method: Firstly modal parameters of linear structures undergoing white signal, stationary random signal and non-stationary ambient excitation are identified; Secondly periodic signals in random excitation signals can be found.更多还原