Session: 09-02-07 Wind Energy: Fatigue Analysis

Submission Number: 181212

Construction and Validation of Load Transfer Numerical Model for Strength Check of Concrete Floating Platforms 

    With the development of offshore wind power towards deep and far seas, the research and development of floating offshore wind turbine (FOWT) platforms have become a hot spot. Concrete floating bodies, with advantages of low cost, high durability, excellent damping characteristics and superior anti-fatigue performance, have gradually become an important alternative to traditional steel floating bodies. In practical engineering, the overall strength check of floating platforms under wave loads is a key link to ensure structural safety and economy. Currently, frequency-domain hydrodynamic analysis software such as DNV SESAM HydroD can accurately calculate the first-order and second-order wave forces on floating bodies in wave environments, but cannot directly conduct structural strength analysis for nonlinear materials like concrete. Meanwhile, finite element software (e.g., Abaqus) possesses powerful capabilities for nonlinear material and structural analysis, yet lacks professional wave load calculation functions. This disconnection leads to the reliance on manual processing for load transfer during the design processes of concrete floating structures, such as wall thickness and reinforcement arrangement, resulting in problems of low efficiency and difficult-to-guarantee accuracy. It not only increases the uncertainty in engineering design, but may also overlook critical load effects due to improper handling, thereby posing potential risks to structural safety.

    This paper proposes an independently programmed load transfer method, which automatically imports wave force results calculated in the frequency domain into finite element software through a data interface program, thereby realizing the overall structural strength check of concrete FOWT platforms. The method includes: (1) extracting wave force time-history data of each node of the floating body from frequency-domain calculation files; (2) performing data format conversion and interpolation processing through programs; (3) applying the processed loads to the finite element model in the form of node forces; (4) conducting structural strength and fatigue analysis considering the nonlinear constitutive relationship of concrete materials.

    To verify the accuracy of the method, the structural responses calculated by this method are compared with the results from other finite element software. The results show that the errors of structural displacement and stress responses are within an acceptable range (less than 5%), and the wave force transfer accuracy is high. This method can be effectively applied to the overall strength check of concrete FOWT platforms, filling the technical gap between hydrodynamic software and finite element software in the analysis of concrete floating structures. It provides an efficient and accurate integrated strength check solution for the industry, and has important engineering practical value for promoting the large-scale application of concrete floating bodies in deep-sea and far-sea wind power projects.

Keywords:Floating wind power platform; Concrete floating body; Wave force transmission; Strength check

Presenting Author: Lingyue Zhang State Key Laboratory of Coastal and Offshore Engineering，Ocean University of China

Presenting Author Biography: Master's Student, Ocean University of China
Research Field: Offshore Wind Power Structures.

Authors:

Teng Huang CRCC Harbor & Channel Engineering Bureau Group Co., Ltd.
Lingyue Zhang State Key Laboratory of Coastal and Offshore Engineering，Ocean University of China
Xingyu Meng CRCC Harbor & Channel Engineering Bureau Group Co., Ltd.
Kun Xu State Key Laboratory of Coastal and Offshore Engineering, Ocean University of China
Yujing Chen State Key Laboratory of Coastal and Offshore Engineering, Ocean University of China