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Generalized Quasi-Static Mooring System Modeling with Analytic Jacobians

Journal Article · · Energies
DOI:https://doi.org/10.3390/en17133155· OSTI ID:2405053
 [1]
  1. National Renewable Energy Laboratory (NREL), Golden, CO (United States)
This paper presents a generalized and efficient method for quasi-static analysis of mooring systems, including complex scenarios such as when shared mooring lines interconnect multiple floating wind or wave energy devices. While quasi-static mooring models are well established, most published formulations are focused on specific applications, and no publicly available implementations provide efficient handling of large mooring system networks. The present formulation addresses these gaps by: (1) formulating solutions for edge cases not typically supported by quasi-static models; (2) creating a fully generalized model structure such that any combination of mooring lines, point masses, and floating bodies can be assembled; and (3) deriving analytic expressions for the system Jacobians (stiffness matrices) so that systems with many degrees of freedom can be solved efficiently. These techniques form the theory basis of MoorPy, an open-source mooring analysis library. The model is demonstrated on nine scenarios of increasing complexity with features of interest for offshore renewable energy applications. When compared with steady-state results from a lumped-mass dynamic model, the results show that the quasi-static formulation accurately calculates profiles and tensions and that its analytic approach provides more efficient and reliable computation of system stiffness matrices than finite-differencing methods. These results verify the accuracy of the MoorPy model.
Research Organization:
National Renewable Energy Laboratory (NREL), Golden, CO (United States)
Sponsoring Organization:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Wind Energy Technologies Office
Grant/Contract Number:
AC36-08GO28308
OSTI ID:
2405053
Report Number(s):
NREL/JA--5000-89605; MainId:90384; UUID:2563e9e6-9207-4e9e-aa40-ae57366a0a85; MainAdminId:72629
Journal Information:
Energies, Journal Name: Energies Journal Issue: 13 Vol. 17; ISSN 1996-1073
Publisher:
MDPICopyright Statement
Country of Publication:
United States
Language:
English

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An Engineering Assessment Of The Validity Of The Quasi-Static Approach To Semisubmersible Mooring Design conference January 1986
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