摘要
傅里叶分析的信号处理方法对非线性、非平稳信号的处理能力差,传统的模态参数识别方法也存在阻尼比识别精度不高的问题。基于Hilbert-Huang变换和随机减量技术提出了一种新的、实用的模态参数识别方法,首先对结构振动信号进行滤波处理和经验模态分解,得到若干阶本征模态响应,然后利用随机减量技术提取自由衰减响应,进而由Hilbert-Huang变换得到信号的瞬时特性,最后结合模态识别的基本理论识别结构的模态频率和模态阻尼比。为了验证这一方法的有效性,对12层钢筋混凝土框架模型振动台试验一测点的加速度记录进行了处理,识别了模态参数,识别结果与其它识别方法及有限元分析结果的对比表明该方法识别模态频率是可靠的,而模态阻尼比识别的精准性仍然难以确认。
The approaches based on Fourier analysis are not capable to process nonlinear and non-stationary signal. In addition, most of traditional identification methods suffer from low precision for identifying damping. An approach to identify the structural modal parameters based on Hilbert-Huang transform （HHT） and random decrement tech- nique （RDT） is proposed. First, the original vibration signal is filtered, and several intrinsic mode functions are obtained by empirical mode decomposition （EMD）. Then, the free-decay response of the structure is extracted by RDT, and the instantaneous characteristics of the original signal are obtained via Hilbert Transform （HT）. Finally, the basic modal analysis theory is adopted to identify modal frequencies and modal damping ratios. In order to validate this approach, the original acceleration record from the shaking table test of a 12-storey RC frame model is processed and modal parameters are identified by the proposed approach. Identified results are also compared with the results from other identification algorithms and finite element analysis. Comparison indicates that the proposed ap- proach is reliable to identify modal frequencies. But it is still difficult to confirm the precision of the identified modal damping ratios.
出处
《世界地震工程》
CSCD
北大核心
2011年第1期72-77,共6页
World Earthquake Engineering
基金
甘肃省科技攻关项目(2GS057-A52-008)
