Time-domain distributed modal parameter identification based on mode decomposition of single-channel vibration response

In the context of wireless intelligent sensing and edge computing, a suitable way of modal parameter identification (MPI) for vibration monitoring of engineering structures is to use a distributed scheme where the majority of computing tasks are deployed to the sensor ends. This paper presents a time-domain algorithm called free-vibration-response based mode decomposition (FVRMD) for distributed MPI, which directly estimates frequency, damping ratio, initial amplitude, and initial phase from the vibration signals. Since FVRMD only relies on a single-channel input, it can be independently and synchronously deployed on each intelligent sensor in the distributed MPI scenario. Additionally, we provide a remote integration scheme to extract structure modal shape and the final representative frequency and damping ratio from the identified parameters at the edge. The proposed method is verified by analyzing vibrations in a simulated and experimental beam structure, as well as a real suspension bridge. Results demonstrate that the method is accurate and stable in estimating frequency and damping ratio, and its ability to identify modal shape is close to that of the centralized method.