Abstract:
The discrete-time rational approximation (DRA) function is an important tool to convert the frequency response function of semi-infinite soil into a time-domain model. The DRA function has the same stability and accuracy as the time-domain model. Current studies on DRA function focus only on single-degree-of-freedom system. In the paper, stability conditions for rational approximate systems with multiple degrees of freedom (MDOF) based on the linear control theory is provided. In combination with the stability condition with the genetic-sequential quadratic algorithm, a parameter identification method for frequency response function of MDOF systems is developed, which ensures the stability and accuracy of the MDOF system. Numerical simulation for the rational approximation of MDOF systems with different dimensions shows that the proposed method can guarantee the stability and accuracy of rational approximation for MDOF systems.