基于小波和奇异值理论的西安钟楼模态参数识别

Modal parameter identification of Xi′an bell tower based on the wavelet and singular value theory

在对国家重点文物保护单位西安钟楼进行强噪声环境激励下振动监测的基础上,应用自然激励法采用不同测点的传感器记录的加速度信号的互相关函数代替系统的脉冲响应函数,选取适当的小波函数、小波尺度、中心频率和带宽频率对互相关函数进行小波分析,并根据小波变换系数的模的相角和对数导数识别频率和阻尼比信息,实现了基于小波和奇异值理论的方法对西安钟楼模态参数进行识别,并对识别结果进行对比分析,验证基于小波和奇异值理论的方法识别古建筑木结构模态参数的可行性,为古建筑的保护和研究工作提供参考。

On the basis of vibration monitoring under strong noise environment excitation of the national key cultural relics protection site Xi’an Bell Tower,the paper used the natural excitation technique to replace the impulse response function with the inter-correlation function of the acceleration signal,which was recorded by sensors at different measuring positions.The Cross-correlation function was analyzed then by means of selecting Wavelet function,wavelet scale,center frequency and bandwidth frequency.Phase angle of modules of wavelet transform coefficient and logarithmic derivative recognition frequency as well as damping ratio were also required to achieve the modal parameters of the building based on the wavelet and singular value theory.The comparative analysis of the recognition results verified the feasibility of identifying the modal parameters of the ancient building wood structure based on the wavelet and singular value theory,and provided reference for the protection and research of ancient buildings.