Displacement and stress monitoring of a chemical tanker based on inverse finite element method

Real-time reconstruction of full field structural displacements, strains, and stresses by using surface strain measurements obtained from on-board strain sensors is commonly referred to as shape- and stress-sensing. For this purpose, a computationally accurate, robust, and rapid algorithm named as inverse Finite Element Method (iFEM) was recently developed. The main goal of this study is to perform displacement and stress monitoring of a typical chemical tanker mid-ship based on iFEM methodology. The numerical implementation of the iFEM algorithm is done by considering four-node inverse quadrilateral shell (iQS4) element. In order to demonstrate the capability of the current approach, a long barge that has a cross-section identical to a typical chemical tanker is modeled with iQS4 elements. Then, hydrodynamic loads of the barge for a certain frequency of waves are calculated by using in-house hydrodynamic software. Then, these forces are applied to a FEM model of barge and structural response is computed by using in-house finite element software. The results obtained from FEM analysis is utilized as a source to simulate in-situ strain data used in iFEM analysis as input. Finally, iFEM and FEM displacements are compared and the effects of locations and number of sensors on iFEM solution accuracy are discussed