基于时-频域信息的结构系统识别方法研究

结构响应的时域、频域信息均可用来对结构模型进行修正。该文提出频域信息与时域信息相结合的方法,对结构参数以及荷载进行评估。首先,从结构测量加速度信息中提取结构的频域特性,对结构模型进行较为粗略的修正,优化结构模型的振型、频率,使其与测量信息一致。其次,利用时域信息,在状态空间对结构运动微分方程进行零阶离散化,采用正则化方法对模型进行荷载识别,同时基于约束优化方法对结构模型参数进行进一步修正。应用模型缩聚方法,保证计算精度的情况下减少结构模型参数修正和荷载识别的计算量。在数值仿真计算中,基于框架结构的不完备地震时程响应记录,对结构损伤状况进行评估。结果证明,即使在有噪声的情况下,该文提出的结构状态方法依然能够很好地识别结构损伤程度、位置。最后,通过14层加层隔震剪力墙结构的振动台试验进一步验证该文提出的结构参数与荷载识别方法。

Structural system identification based on frequency-time domain information

The information in time domain and frequency domain can be used for structural model updating.A frequency-time domain method is proposed for structural model updating and external excitation identification in this paper.First,the parameters in frequency,such as frequency and mode shape,are calculated from the acceleration and structure model updating is conducted with these parameters.Second,a state space force identification method is proposed.The model updating is also updated in the second stage.A regularization method is utilized in the force identification and constraint optimization method is applied in the structural model updating.IIRS condensation method is used for computational effort.In the numerical simulations,a frame structure is studied.The structural model is updated with white noise excitation.The structure damage is detected with the incomplete measured information during the earthquake excitation.A 14-storey shear wall building is investigated to validate the proposed method for force identification and damage detection.The structure response is reconstructed with small error.Promising identification results can be obtained with the proposed method even when the measured response is polluted with 10% noise.