基于结构强震记录的结构时变模态参数识别

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振动与冲击 ›› 2010, Vol. 29 ›› Issue (5) : 171-175.

论文

基于结构强震记录的结构时变模态参数识别

公茂盛1，2;鹿嶋俊英3;谢礼立1，2;欧进萍2

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STRUCTURAL TIME-VARYING MODAL PARAMETERS IDENTIFICATIONBASED ON ITS STRONG MOTION RECORDS

GONG Mao-sheng1,2;Toshihide KASHIMA3;XIE Li-li1,2;OU Jin-ping2

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文章历史 +

摘要

为研究结构在地震过程中动力特性变化和损伤过程，为结构地震损伤评估提供可靠依据，采用递归式在线系统辨识算法RARX模型，利用结构强震记录识别了结构时变模态参数。以一座6层钢筋混凝土框架结构为例，识别了其时变自振频率、阻尼比和等效刚度。结果发现：在小地震动作用下，结构自振频率随时间几乎不发生改变；在大地震动作用的整个时间过程中，结构自振频率随时间逐渐降低，降低到一定程度到达最低点后，频率开始回升，直至地震结束，但最后不能回升到初始值，说明经历大震发生损伤的结构在震后性能会有所恢复；结构等效刚度变化趋势和自振频率相同，但在大震中下降比频率下降大的多；结构阻尼比在经历大震发生损伤后增大。结果可供结构地震损伤预测及结构震后安全鉴定参考。

Abstract

To study the changes of structural dynamic characteristics and the structural seismic damage process during earthquakes for structure seismic damage assessment purpose, the time-varying modal parameters are identified based on the strong motion records by using on-line system identification method RARX model. For one example, the natural frequency, damping ratio and equivalent stiffness of a 6-story reinforcement concrete frame structure are identified from its strong motion records during two earthquakes, one is small earthquake, and the other is great earthquake. The results show that the natural frequency does not change during small earthquake. In great earthquake, the natural frequency decreases gradually until it reaches the lowest point value, and then increases until the end of the earthquake but it can not be recovered to the initial value. That means the performance of structures could be recovered to a certain extent after the earthquake. The equivalent stiffness is changed with the same trend as natural frequency, but decreases much greater than that of natural frequency. However, the structural damping ratio increases after damage under the excitation of great earthquake. The results can be referenced by the damage detection and prognosis.

导出引用

公茂盛;鹿嶋俊英;谢礼立;欧进萍. 基于结构强震记录的结构时变模态参数识别[J]. 振动与冲击, 2010, 29(5): 171-175

GONG Mao-sheng;Toshihide KASHIMA;XIE Li-li;OU Jin-ping. STRUCTURAL TIME-VARYING MODAL PARAMETERS IDENTIFICATIONBASED ON ITS STRONG MOTION RECORDS[J]. Journal of Vibration and Shock, 2010, 29(5): 171-175