Abstract :
[en] The current climate crisis has propelled economies to increase the proportion of low-carbon renewable sources in their energy portfolios, resulting in a surge in the installed capacity of renewable energy installations such as offshore wind farms. The development of Floating Offshore Wind Turbines (FOWTs) technology has been an inflection point, expanding operations to deeper waters where more consistent and stronger winds are available. While most of the FOWT prototypes tested so far are made of steel, a growing interest in Reinforced Concrete (RC) and Prestressed Concrete (PC) has emerged due to their cost advantages, stable market prices, longer service life, and lower carbon footprints. This shift prompts a reassessment of design standards to account for the structural particularities of FOWTs with RC/PC floaters, including Accidental Limit States (ALS), given the constant exposure of floating wind farms to ship collisions. This thesis investigates collisions between ships and FOWTs with RC/PC floaters using two distinct modeling approaches. The first consists of Non-Linear Finite Element (NLFE) models with explicit representations of concrete, rebars, and tendons using solid and beam elements; while the second consists of simplified formulations that encompass classical plate theory, yield-line analysis, and a computationally inexpensive layered shell. In these formulations, an algorithm describing the collision kinematics, incorporating rigid-body motions and hydrodynamic effects, is developed and used along MCOL, a large-rotation rigid-body dynamics solver. These simplified formulations aim to reduce the computational expense that is often encountered in NLFE analyses, making them suitable in the preliminary design stages for gathering valuable information regarding the vulnerability of FOWTs to collision events.
