Theoretical modeling of simplified offshore wind turbines with monopile support under multiple environmental load coupling

Abstract

A theoretical framework is formulated to examine the simplification methodology for monopile-supported offshore wind turbine systems (OWTs), where soil-monopile interactions are represented as a spring-damper mechanism under multi-hazard conditions involving earthquake, wave, and wind loads. The study begins by establishing an integrated OWTs model incorporating interdependent physical phenomena: three-dimensional spring-damping elements characterize soil-monopile dynamics, hydrodynamic impedance functions quantify water-monopile interactions in submerged conditions, linearized wave equations govern wave loads, while wind loads acting on rotor blades. The dynamic behavior of OWTs is subsequently analyzed through three methodological components: implementation of domain-specific boundary constraint formulations, decomposition of scalar potential fields, and application of state-space transfer matrix techniques. Comparative validation protocols demonstrate the computational precision of the proposed non-simplified analytical framework relative to established reference methodologies, while systematic benchmarking reveals critical distinctions between this rigorous solution and conventional spring-damper approximations. Parametric sensitivity investigations are subsequently conducted using the developed model to quantify influential design variables. These analytical advancements establish a theoretical foundation for optimized numerical modeling of offshore wind energy infrastructure, particularly in addressing the multi-physical coupling inherent in monopile-supported structural systems.