On Wave Field Kinematics Estimation from Structural Vibration Measurements Via Physics Informed Latent Force Models

Abstract

This study presents the application of the recently introduced Physics Informed Latent Force Models (PILFM) for estimating structural responses and wave kinematics (i.e., water particle velocity and acceleration) in the vicinity of an offshore structure, where a limited number of vibration responses are measured. This can enhance the accuracy of estimated structural responses, such as local stresses, that can be used for assessing the remaining fatigue life of the structure. PILFM integrates a model of the structural system that describes the structural vibration of the structure under wave loading, with known wave theories that describe the spatio-temporal behavior of the waves. A data-driven state space model is obtained based on the wave theories, and a Kalman Filter and Smoother are employed for the efficient estimation of the structural response and the wave kinematics. The current study presents a proof-of-concept of the proposed methodology, illustrated via a 2D structure subjected to stochastic waves. A few structural response measurements enable the estimation of the field kinematics in the vicinity of the structure and the full structural response.