环境激励下房屋建筑阻尼比的识别方法

阻尼比是结构动力分析的重要参数之一,阻尼比的准确取值是结构动力响应准确分析的前提.由于阻尼机理非常复杂,对阻尼比的取值一般通过实测得到.传统的模态参数识别方法同时需要已知激励和响应信号,但对实际建筑结构,激励施加存在困难.探讨了基于环境激励下的模态识别方法,利用环境激励下的结构振动响应数据,探讨了采用随机减量法和ITD(Ibrahim Time Domain)法相结合,有效地识别实际建筑结构的模态参数的方法.工程实例识别结果表明,该方法不仅能准确识别出结构的模态频率,也能相对准确地得到结构的模态阻尼比.

Study on the identification method of damping for the building under ambient excitation

Damping ratio is one of the most important parameters in structure dynamic analysis and the exactly measured damping ratio is a necessary condition for dynamic response analysis.Because the mechanism of damping is very complex,the damping ratio is usually obtained by measuring.For the traditional mode parameter identification method,exciting signal and response signal are necessary.But to excite a real structure and then get the response signal can't be realized.In this paper,a new mode parameter identification method is proposed based on the exiting environmental.The structure response excited by environmental factors is measured.The structure response data are analyzed by random decrement technique and ITD(Ibrahim Time Domain).The results suggest that this new method could not only exactly identify the structure vibration frequency,but also the mode damping ratio.