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提出了一种基于频域空间域分解(Frequency and Spatial Domain Decomposition,FSDD)的运行模态分析方法。该法将同时具有输入和输出的试验模态分析的经典方法———复模态指示因子(Complex Mode In-dicator Function,CMIF)法拓展到了仅有输出响应的运行状态模态分析。FSDD法采用奇异值分解将信号空间和噪声空间分离开来,把奇异值曲线作为模态指示的依据,以奇异值向量作为加权函数得到每一阶模态的增强功率谱(Power Spectrum Density,PSD),进而在频域内对增强PSD曲线进行最小二乘拟合以得到准确的模态频率和阻尼参数。采用了一个二层楼仿真算例和在欧洲广为人知的瑞士Z24公路大桥实测算例来验证FSDD算法。
A new operating mode analysis method based on Frequency and Spatial Domain Decomposition (FSDD) is proposed. This method expands the CMM method, which has both input and output test modal analysis, to modal analysis of operational modes with only output response. The FSDD method uses the singular value decomposition to separate the signal space from the noise space. The singular value curve is used as the basis for the modal indication. The singular value vector is used as the weighting function to obtain the power spectrum density (PSD) ), And then in the frequency domain enhanced PSD curve least squares fit to get accurate modal frequency and damping parameters. The FSDD algorithm is validated using a two-floor simulation study and a real-world example of the Swiss Z24 highway bridge, which is widely known in Europe.