Health monitoring of time-varying stochastic structures
by latent components and fuzzy expert system

M. M. Ettefagh and M. H. Sadeghi

Vibration and Modal Analysis Laboratory, Department of Mechanical Engineering, University of Tabriz, Tabriz 51666, Iran

Abstract: In this paper, a novel parametric model-based decomposition method is proposed for structural health monitoring of time-varying structures. For this purpose, the advanced Functional-Series Time-dependent Auto Regressive Moving Average (FS-TARMA) technique is used to estimate the parameters and innovation variance used in the parametric signal decomposition scheme. Additionally, a unique feature extraction and reduction method based on the decomposed signals, known as Latent Components (LCs), is proposed. To evaluate the efficiency of the proposed method, numerical simulation and an experimental study in the laboratory were conducted on a time-varying structure, where various types of damage were introduced. The Fuzzy Expert System (FES) was used as a classification tool to demonstrate that the proposed method successfully identifies different structural conditions when compared with other methods based on non-reduced and ordinary feature extraction.

Keywords: parametric modeling; signal decomposition; feature extraction/reduction; fuzzy classification