Damage analysis and detection under varying environmental and operational conditions using a chaos theory methods

Abstract

The paper is devoted to problem of analysis, identification and prediction of the presence of damages, which above a certain level may present a serious threat to the engineering (vibrating) structures such as different technical systems (hydrotechnical equipment, hydroelectrical station engines, atomic reactors ones etc). Usually change of structural dynamic properties due to environmental, operational and other effects allows to determine the existence, location and size of damages. We present and apply an effective computational approach to modelling, analysis of chaotic behaviour of structural dynamic properties of the engineering structures. The approach includes a combined group of non-linear analysis and chaos theory methods such as a correlation integral approach, average mutual information, surrogate data, false nearest neighbours algorithms, the Lyapunov’s exponents and Kolmogorov entropy analysis, nonlinear prediction models etc. As illustration we present the results of the numerical investigation of a chaotic elements in dynamical parameter time series for the experimental cantilever beam (environmental conditions are imitated by damaged structure, variating temperature, availability of a pinknoise force). For the first time we list the numerical data on topological and dynamical invariants, i.e., correlation, embedding, Kaplan-Yorke dimensions, Lyapunov’s exponents and Kolmogorov entropy etc.