Real time structural loads monitoring for a large high-speed wave-piercing catamaran using numerical simulation and linear regression

High-speed wave-piercing catamarans encounter several kinds of global loads; some are similar to those for traditional monohull sea going ships, such as longitudinal bending moment (LBM), shear, torsional and dynamic wave slamming loads. However, due to the twin-hull configuration of the catamaran, additional types of global load are introduced, such as pitch connecting moment (PCM) and transverse bending moment (TBM). This paper investigates the structural health monitoring (SHM) of a high-speed wave-piercing catamaran through prediction of global loads from real-time processing of signals from a large distributed network of strain and acceleration sensors. Finite element method (FEM) and computational fluid dynamic (CFD) analyses at full scale are deployed to simulate catamaran response to loading cases and sea waves. A transformation equation based on a linear regression of the FEA results is applied to measured signals to convert strain signals to global loads. Global loads are also estimated using rigid body dynamics alongside computational fluid dynamics (CFD) simulation of HSV2. Motion and strain data collected from sea trials runs of a 98m high-speed wave-piercing catamaran (HSV-2) are used to confirm the proposed method. The sea trials runs of HSV2 Incat catamaran have been carried out in 2004 in a wide range of sea states, ship speed, wave heights, wave periods and sea wave headings. Longitudinal bending moment (LBM) is estimated for headseas run at 20 knots using two methods based on CFD and FEM simulation.