Investigating foundation damping for OWTs using small strain hardening model calibrated with element scale tests
Investigating foundation damping for OWTs using small strain hardening model calibrated with element scale tests
Offshore wind turbines (OWTs) are subjected to cyclic excitations from the environmental and mechanical loads which control the fatigue lifetime of the structural components and can govern the overall design optimisation of the OWT. The growth of OWT size in recent years has led to a greater need to accurately quantify the different sources of damping that significantly influence the dynamic response of offshore wind turbines. Incorporating total damping in integrated numerical analysis will yield more realistic values of structural loads and bending moments which can be used to produce cost effective structural support design for modern size OWTs. One source of damping that is often overlooked is the contribution of the foundation to attenuate the dynamic response through the hysteretic behaviour of the surrounding soil. Thus, this research aims to accurately calculate the global foundation damping for a reference 15 MW OWT through calibrating a constitutive soil model to cyclic triaxial tests, and then implementing full 3D finite element FE analyses to capture the evolution of soil damping with monopile displacement at the mudline level. The small strain hardening soil model (HSsmall) was chosen due to its capability to exhibit non-linearity and stress-strain loops upon load reversals. Time domain free-decay analyses are executed in order to evaluate soil damping through logarithmic-decrement approach.
M. Barzan; S. Kasyap; David Igoe
18th European Conference on Soil Mechanics and Geotechnical Engineering (ECSMGE2024)
E - Environment, water and energy
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