On the use of the inverse finite element method to enhance knowledge sharing in population-based structural health monitoring
Giulia Delo, Rinto Roy, Keith Worden, Cecilia Surace
Abstract
Efficient Structural Health Monitoring (SHM) is critical for ensuring safety and improving the operation and maintenance of aerospace structures. This study focusses on advanced shape-sensing methods, such as the inverse Finite Element Method (iFEM), which can estimate the complete displacement field of a structure based on a restricted number of strain measurements, fostering continuous and real-time monitoring. This approach additionally provides valuable insights into the dynamic behaviour of a structure by extracting its Frequency Response Functions (FRFs) and modal properties to perform vibration-based SHM. However, effectively extending SHM to a fleet or population of structures would require a significant amount of data for each one, which may be unavailable or incomplete. A population-based Structural Health Monitoring (PBSHM) strategy can solve data scarcity by sharing knowledge between similar structures via transfer-learning algorithms. In PBSHM, handling data from diverse sources is paramount for achieving accurate results. Therefore, this study integrates iFEM into the PBSHM framework, enhancing knowledge transfer by harmonising fibre-optic strain measurements to vibration-based features and providing reliable source data to inform diagnostics on similar structures. The proposed approach is validated on a population of laboratory-scale steel aircraft subjected to specific operating and damage conditions tested using three different sensor setups. • The iFEM provides insights into the dynamic behaviour of structures and allows to determine the FRFs from strain data. • iFEM facilitates the extraction of modal properties, which are crucial for performing vibration-based SHM. • PBSHM addresses data scarcity issues via knowledge sharing, allowing for effective monitoring across a fleet of structures. • iFEM is integrated into PBSHM, where reconstructed displacements are used to improve damage diagnosis in target structures.