在线监测环境下土木结构的模态识别研究

建立在线监测环境下结构考虑时效的模态识别计算方案。采用基于各测点加速度响应互功率谱的频域多参考点模态识别法来实现结构模态参数的抽取，从而绕过了监测环境下激励监测的技术难题；并用频域的平均法使识别参数的拟合曲线平滑和发现参数的变化趋势。通过对美国结构健康监测研究小组公布的Benchmark问题的第一阶段解析模型模拟加速度响应数据的识别，表明本文采用的算法有较好的识别精度和识别速度，是一个可行的在线监测环境下的模态识别计算方案。

Research on structure modal identification under online monitoring conditions

A structure modal identification scheme with time effect taken into account under online monitoring condition is established in this paper. Using the frequency domain multi-reference modal identification methods, which is based on the cross power spectra density of multi-measurement-point acceleration responses, the modal parameters of the structure are extracted. As a result, the difficulty of measurement of the excitations applied to the structures in service is avoided successfully. A frequency domain even methods is used to make the fit curves of the frequency spectral identified more even and smooth. The results of the acceleration responses simulated by the first phase analytical model of the benchmark problem issued by US SHM research task show that the arithmetic adopted in this paper performs an identification with good precision and fast speed. The scheme presented in this paper has a good feasibility for the modal identification under the online monitoring conditions.