Hydroelastic Behavior of a Converted FPSO Platform Under Head Waves Excitation

Abstract Although the rigid body hypothesis is broadly used when studying the dynamics of floating bodies, it is known that this is not the best approach, as these structures can present elastic deformations, such as vertical bending. The lack of consideration of the hydroelastic behavior of a floating body during its design stage can lead to structural problems, such as fatigue damage, possibly causing the operation to become inviable before the end of its life cycle. This study focuses on the vertical bending moment response of a converted FPSO, a ship-shaped platform, under head waves excitation. One of the main differences between FPSOs and other ship-shaped structures is the fact that they do not present forward speed during their operation. Numerical simulations were performed to assess its hydroelastic response and validated through model tests in an ultra-reduced scale in a wave channel. The simulations considered the wall effect due to the wave channel, but simulations in open water conditions were also performed so full-scale extrapolation was possible. The model used in the experiments consisted of a segmented hull connected by an aluminium backbone providing the required bending stiffness, which was instrumented with calibrated strain gauges so that its strain measurements could be associated with the vertical bending moment acting on the beam.