环境激励下基于改进经验小波变换的土木工程结构模态参数识别  

Improved empirical wavelet transform for modal parameters identification of civil engineering structures under ambient excitations

作　　者：万熹 黄天立[1] 陈华鹏 WAN Xi;HUANG Tian-li;CHEN Hua-peng(School of Civil Engineering,Central South University,Changsha 410075,China;School of Civil Engineering and Architecture,East China Jiaotong University,Nanchang 330013,China)

机构地区：[1]中南大学土木工程学院,湖南长沙410075 [2]华东交通大学土木建筑学院,江西南昌330013

出　　处：《振动工程学报》2020年第2期219-230,共12页Journal of Vibration Engineering

基　　金：国家自然科学基金资助项目(51478472,U1734208);国家重点研发计划项目(2017YFB1201204);英国皇家工程院牛顿基金资助项目(Reference NRCP/1415/14);中南大学研究生自主探索创新基金资助项目(2018zzts664)。

摘　　要：针对经验小波变换(EWT)识别噪声信号模态参数时,由于傅里叶频谱易受噪声影响而频带划分不准确等问题,提出了一种基于Burg算法的自回归功率谱替代傅里叶频谱的信号频带划分技术,结合随机减量技术和基于Hilbert变换的单分量模态参数识别方法,提出了环境激励下基于改进经验小波变换的土木工程结构模态参数识别方法。典型模拟信号、美国土木工程师学会ASCE Benchmark数值模型以及台风激励下香港汀九斜拉桥的模态参数识别结果验证了方法的正确性、有效性和适用性。研究结果表明:基于自回归功率谱的信号频带划分技术,可更准确地估计信号频带边界,隔离噪声;基于改进EWT方法识别的结构模态参数更准确,精度高于基于小波变换的方法,且能有效地识别环境激励下实际土木工程结构的低阶自振频率和阻尼比。The frequency band division is not accurate due to the noise effect on the Fourier spectrum when the empirical wavelet transform(EWT)is used for identifying the modal parameters of noisy signals.An improved empirical wavelet transform(IEWT)based procedure is proposed in this study to identify the modal parameters of civil engineering structures under ambient excitations.In the proposed IEWT-based procedure,the autoregressive(AR)power spectrum based on the Burg algorithm is adopted to substitute the Fourier spectrum for the frequency band division,the random decrement technique(RDT)and the Hilbert transform(HT)based mono-component modal parameter identification method are both included.A typical simulated signal,the ASCE Benchmark structure under the white noise excitations and the Ting Kau Bridge under the typhoon excitations are used to validate the correctness,effectiveness and applicability of the proposed procedure.The identified results show that the proposed AR power spectrum-based frequency band division technique can accurately estimate the frequency band boundaries and isolate noise.The proposed IEWT-based identification procedure can effectively identify the low-order natural frequencies and damping ratios of the real civil engineering structures under ambient excitations.The identified results are more accurate than those from the wavelet transform(WT)based method.

关 键 词：模态参数识别 土木工程结构 斜拉桥 经验小波变换 BENCHMARK模型 

分 类 号：TU311.3[建筑科学—结构工程] U448.27[建筑科学—桥梁与隧道工程]