摘要
提出了FM-EMD(调频EMD)方法,克服了原EMD方法在模态频率相近情况下的振型混淆问题。通过功能扩展,实现了"可选择性EMD分解":既可以对实测信号的某一频段进行针对性分解,也可根据信号的实际情况,选择从频谱高端或从频谱低端开始分解,以排除无效信号成分的干扰,并突出有效信号成分。所提方法具有很强的工程适应能力,适用于桥梁结构的运行模态辨识。通过对某120米跨径的钢管混凝土桁梁桥的运行模态实验,辨识得到了结构的频率、振型和阻尼比。通过与成熟辨识方法的比对,得出以下结论:该方法可以得到较高精度的频率值,较好形制的模态振型,但会低估模态阻尼值,频率辨识误差不超过1%,模态阻尼值低估不超过10%。
Frequency modulated empirical mode decomposition （ FM - EMD） method is proposed for the operation- al modal test of bridges. The problem of mode mixing of the original EMD method has been solved. The proposed method performs the decomposition on the selected frequency bands to maximize the ＂useful＂ information in the sig- nal. It can also perform the decomposition either from the higher frequency end or from the lower frequency end to minimize the effect of unwanted components in the signal. The method is suitable for the operational modal tests of bridges. The effectiveness of the method is demonstrated by a modal test on a 120m - span concrete filled steel tu- bular truss bridge. The comparison study shows that the proposed method may provide modal frequencies and mode shapes in high precision but will always underestimate the modal damping. The identification error is below 1% for the frequency and 10% for the modal damping.
出处
《世界地震工程》
CSCD
北大核心
2015年第4期159-164,共6页
World Earthquake Engineering
基金
河南省科技攻关项目(112102310453)
