HHT结合NExT法识别结构参数

Identification of Structural Parameters Based on HHT and NExt

信号处理方法在地震工程领域有着广泛的应用,尤其是在结构参数识别方面。Hilbert-Huang变换(HHT)是一种新的信号处理方法,它与NExT法相结合可以识别结构的模态频率、阻尼比和振型。对于剪切型结构,本文基于柔度法推导了层间刚度的计算公式,公式表明,只要已知任一完整模态,就能计算出所有层的层间刚度。在此基础上,本文根据堆聚质量法的原理将喜来登环球旅馆简化四层剪切结构,利用其在1994年北岭地震中所取得的强震记录,通过HHT与NExT法相结合,识别了结构的前三阶模态频率、阻尼比和振型,并计算出其层间刚度。最后,应用弹性时程分析法,利用已识别出的结构参数,计算结构的地震反应,计算结果与强震记录对比表明,识别出的结构参数是有效的。

Signal processing approaches are widely used in the earthquake engineering field, especially in the identification of structural parameters. Hilbert-Huang Transformation （HHT） is a new signal processing approach, which can be used to identify the modal frequency, damping ratio and vibration mode of the structure incorporated with NEXT. In addition, by using of the flexibility method, the calculation formulas of the interlaminal stiffness of shear-type structure are derived, which indicate that all of interlaminal stiffnesses could be found out as long as any one integral mode is given. After that, based on the lumped mass method, Sheraton Universal Hotel is firstly reduced as the four- floor shear-type structure, then, the first three modal frequencies, damping ratios and vibration modes of this structure are identified by using of HHT and NEXT, the referenced data are the strong motion records obtained in North Bridge earthquake in 1994, and the interlaminal stiffnesses are worked out. Finally, the earthquake responses caculated by the elastic time history analysis based on the identified structural parameters are compared with the strong motion records, and the result shows that the identified structural parameters are valid.