Laboratory-scale validation of modal expansion for virtual sensing of offshore tubular structures

Digital twin is an emerging approach for structural integrity management and has gained significant attention from both academia and industry of offshore engineering in recent years. While it is a multi-faceted concept, virtual sensing is an indispensable functionality of digital twin. A prevalent technique for implementing virtual sensing is the modal expansion approach, where the responses of non-instrumented areas (i.e., without physical sensors) are predicted by inverse estimation of the structural mode shape amplitude through physical sensing in instrumented areas. However, this method lacks extensive validation, particularly through experimental data obtained in controlled environments. To address this gap, this paper uses wave tank test data from a tubular structure model to validate the modal expansion technique for stress/strain sensing in non-instrumented areas and investigate the associated uncertainties.