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Reliability of Lamb Wave SHM Systems: Influence of Hydrostatic Pressure, Mechanical Loading and Fatigue on the Value of a Damage Index
Abstract
Structural Health Monitoring (SHM) systems can cause changes in paradigms in industrial maintenance, such as a move from time-based to condition-based maintenance, where the integrity of a structure would be continuously monitored and analysed. Lamb Waves are one of the most promising technologies for SHM since they are able to monitor a relatively large area with a relatively small number of sensors, especially when compared to other techniques such as conventional ultrasound and eddy currents. However, there is a need to evaluate the reliability of such systems under operating conditions, so there are several research programs which aim to investigate their response variability when faced with temperature changes, mechanical load cycling and other physical effects. This study is part of a collaboration program between LAMEF and Embraer R&D department. The current paper will present initial results and discussions on the influence of different scenarios on lamb waves systems. Several laboratory tests have been conducted in order to evaluate the influence of conditions commonly imposed on aircraft structures on the signals, such as tension, compression, hydrostatic loads (found in fuel tank). Additionally, a study of structure settling under a cyclic loading was performed. The results show that each kind of load has a different influence on the signals, and it was also observed that the influences may change depending on excitation frequency.
DOI
10.12783/shm2019/32222
10.12783/shm2019/32222