The invention relates to method for identifying operating
modal parameters of a linear time-varying
structure based on memory-restricted
principal component analysis. According to the method, the operating
modal parameters of a
dynamical system with time-varying structural characteristics can be identified by only using unsteady
vibration response signals, the operating
modal parameters of the structure are identified, and the dynamical variation characteristics of the
system can be effectively monitored in real time, thus the method can be applied to
vibration control, equipment fault diagnosis, health monitoring, and
system structure analysis and optimization. The method is characterized in that the parameter characteristics of the
system are identified by only using actual measured response signals, load signals aren't measured, and the method is proven according to mathematical theoretical analysis and experiment, so that a physical significance is endowed to the method. The invention further relates to an operating modal measuring device based on the method, and the device is used for measuring
vibration response signals and identifying the operating modal parameters to obtain the real-time online dynamical characteristic change of the
system structure, thus the device can be applied to fault diagnosis and health monitoring analysis of a large complex
engineering structure (bridge, rail and the like).