Modal parametric identification of distribution type structures based on random decrement technique

Abstract

Technology for partition processing and parallel analysis is essential to realize a dense array of wireless smart sensors network for measuring on large-scale civil structures. Here, a distributed data collecting approach for a system's modal identification was proposed based on the random decrement technique (RDT). The performance of the RDT-based distributed data collecting was tested using a two-side simply supported plate model. Using ISM400 wireless smart sensors, the random decrement function was calculated with the measured vibration acceleration time histories of the plate by adopting the natural excitation technique (NExT). A time domain algorithm integrating NExT and the eigen-system realization algorithm (ERA) was applied to identify modal parameters of the plate and combined with the method of stability diagram (SD) to eliminate false modes. The identification results were compared with those based on the centralized method. It was shown that the plate's modal shapes obtained with the proposed method are close to those obtained with the centralized method using the modal assurance criterion (MAC).