Continuous baseline growth and monitoring for guided wave SHM

Abstract

It has been shown by many authors that temperature effect compensation is a necessity for the realization of a reliable structural health monitoring (SHM) system. However, there exist practical issues related to the acquisition of baseline signals, required for temperature compensation methods to work effectively, such as degenerate baseline signals recorded at the same temperature and a long acquisition period before monitoring is started. An alternative approach for the acquisition of baseline signals is presented in this paper. The algorithm makes the acquisition an evolutionary process, integrated in the damage detection procedures. The algorithm is shown to be successful in generating a concise set of baselines that guarantees efficient performance of temperature compensation methods, leading to computation time and computer memory savings. Its capabilities in detecting simulated abrupt and slowly evolving damages have also been tested.