中文摘要：

提出了一种基于自由响应信号识别时变系统物理参数的子空间方法.该方法以任意组合的位移、速度、加速度响应信号为测量信息,通过对仅利用一组响应信号组成的Hankel矩阵做奇异值分解,识别出等效状态的系统矩阵,然后运用推导出来的通用时变系统的转换矩阵,将等效状态系统矩阵转换成为实际物理状态下的系统矩阵,从而识别出实际系统的刚度、阻尼矩阵.以二自由度弹簧-质量-阻尼模型为算例,研究了突变、线性变化和周期变化三种变化形式下物理参数的识别,并讨论了不同信噪比下噪声对识别结果的影响,仿真算例验证了该方法的正确性和有效性.

英文摘要：

A physical parameter identification method is presented in this paper. For an arbitrarily time-varying system, a se- ries of Hankel matrices are established directly from free response data, which have been obtained through only one experi- ment of the system. The varying equivalent state space system matrices of structures at each moment are then identified by Singular Value Decomposition （SVD） of the Hankel matrix. A varying transformation matrix to transform the identified equivalent system matrices into the physical system matrices is developed to determine the stiffness and damper matrices. Finally, a 2DOF spring-mass-damper model with three kinds of time-varying cases is investigated. Numerical results show that the proposed method is accurate and effective to identify the time-varying physical parameters.