Deformation and stress reconstructions of ship structures by inverse finite element method with single-sided strain measurements

This study proposes an enhanced framework for the real-time reconstruction of displacement and stress fields in ship structures using the inverse finite element method (iFEM). The framework consists of two sequential analysis phases. First, the hull displacement field is reconstructed using a single-sided iFEM from strain measurements that are interpolated to all elements of the hull finite element model. Subsequently, a forward finite element analysis on a comprehensive ship model, which includes the internal structure, with the displacement field reconstructed in the first phase applied as enforced boundary conditions, recovers the stress field, including the contributions of the internal structures. The proposed framework was validated through a numerical simulation of a full-scale Capesize bulk carrier under wave-induced hydrodynamic pressures. In addition, an experiment was conducted in a towing tank using a scaled hydro-structural ship model. The results demonstrate that the proposed framework accurately reconstructs hull girder deformations and stress distributions. These reconstructed displacement and stress fields enable real-time structural health assessments, providing a critical basis for evaluating yielding and fatigue risks. This approach offers a practical and computationally efficient solution for the continuous structural monitoring of large-scale marine vessels, while significantly reducing the constraints and costs associated with sensor installation.