基于小波包分析推导了结构动力系统在不同分析尺度上的状态方程和观测方程,在此基础上研究了结构动力响应在不同分析尺度上的时一频特性以及系统矩阵和测量噪声在各个分析尺度上的递推性。理论分析证明,采用结构动力响应的小波包能量谱进行结构损伤预警具有较好的损伤敏感性和噪声鲁棒性。根据瞬态激励的特性提出对激励和响应的时域互相关序列进行小波包分解得到小波包能量谱,并在此基础上计算结构损伤预警指标。通过一钢筋混凝土板静力承载力的振动试验分析,对板不同受力阶段的损伤状态进行了判别,并与实际损伤程度进行了比较。
The state and observation equations of structural dynamic systems in various analysis scales are derived based on wavelet packet analysis. The time-frequency properties of structural dynamic responses in various scales are then investigated together with the transfer properties of system matrix and observation noise. The theoretical analysis results reveal that structural damage alarming using wavelet packet energy spectrum of the structural dynamic responses has preferable damage sensitivity and noise robusticity. According to the characteristics of instantaneous stimulations, the wavelet packet energy spectrum is obtained using the wavelet packet decomposition of the cross-correlation of stimulation and response signals in time domain, based on which the structural damage alarming index is obtained. Through a vibration testing analysis of a reinforced concrete slab subjected to static loading series, the damage status of the slab during different loading phases are determined and compared with the actual deterioration states.