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Title: Inclusion of Structural Flexibility in Design Load Analysis for Wave Energy Converters: Preprint

Abstract

Hydroelastic interactions, caused by ocean wave loading on wave energy devices with deformable structures, are studied in the time domain. A midfidelity, hybrid modeling approach of rigid-body and flexible-body dynamics is developed and implemented in an open-source simulation tool for wave energy converters (WEC-Sim) to simulate the dynamic responses of wave energy converter component structural deformations under wave loading. A generalized coordinate system, including degrees of freedom associated with rigid bodies, structural modes, and constraints connecting multiple bodies, is utilized. A simplified method of calculating stress loads and sectional bending moments is implemented, with the purpose of sizing and designing wave energy converters. Results calculated using the method presented are verified with those of high-fidelity fluid-structure interaction simulations, as well as low-fidelity, frequency-domain, boundary element method analysis.

Authors:
 [1];  [1];  [1];  [1]
  1. National Renewable Energy Laboratory (NREL), Golden, CO (United States)
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Wind and Water Technologies Office (EE-4W)
OSTI Identifier:
1378880
Report Number(s):
NREL/CP-5000-68923
DOE Contract Number:
AC36-08GO28308
Resource Type:
Conference
Resource Relation:
Conference: Presented at the European Wave and Tidal Energy Conference, 27 August - 1 September 2017, Cork, Ireland
Country of Publication:
United States
Language:
English
Subject:
16 TIDAL AND WAVE POWER; hydroelastic; wave energy converters; WEC; WEC-Sim; design loads; fluid-structure interaction

Citation Formats

Guo, Yi, Yu, Yi-Hsiang, van Rij, Jennifer A, and Tom, Nathan M. Inclusion of Structural Flexibility in Design Load Analysis for Wave Energy Converters: Preprint. United States: N. p., 2017. Web.
Guo, Yi, Yu, Yi-Hsiang, van Rij, Jennifer A, & Tom, Nathan M. Inclusion of Structural Flexibility in Design Load Analysis for Wave Energy Converters: Preprint. United States.
Guo, Yi, Yu, Yi-Hsiang, van Rij, Jennifer A, and Tom, Nathan M. 2017. "Inclusion of Structural Flexibility in Design Load Analysis for Wave Energy Converters: Preprint". United States. doi:. https://www.osti.gov/servlets/purl/1378880.
@article{osti_1378880,
title = {Inclusion of Structural Flexibility in Design Load Analysis for Wave Energy Converters: Preprint},
author = {Guo, Yi and Yu, Yi-Hsiang and van Rij, Jennifer A and Tom, Nathan M},
abstractNote = {Hydroelastic interactions, caused by ocean wave loading on wave energy devices with deformable structures, are studied in the time domain. A midfidelity, hybrid modeling approach of rigid-body and flexible-body dynamics is developed and implemented in an open-source simulation tool for wave energy converters (WEC-Sim) to simulate the dynamic responses of wave energy converter component structural deformations under wave loading. A generalized coordinate system, including degrees of freedom associated with rigid bodies, structural modes, and constraints connecting multiple bodies, is utilized. A simplified method of calculating stress loads and sectional bending moments is implemented, with the purpose of sizing and designing wave energy converters. Results calculated using the method presented are verified with those of high-fidelity fluid-structure interaction simulations, as well as low-fidelity, frequency-domain, boundary element method analysis.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2017,
month = 8
}

Conference:
Other availability
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  • This study explores and verifies the generalized body-modes method for evaluating the structural loads on a wave energy converter (WEC). Historically, WEC design methodologies have focused primarily on accurately evaluating hydrodynamic loads, while methodologies for evaluating structural loads have yet to be fully considered and incorporated into the WEC design process. As wave energy technologies continue to advance, however, it has become increasingly evident that an accurate evaluation of the structural loads will enable an optimized structural design, as well as the potential utilization of composites and flexible materials, and hence reduce WEC costs. Although there are many computational fluidmore » dynamics, structural analyses and fluid-structure-interaction (FSI) codes available, the application of these codes is typically too computationally intensive to be practical in the early stages of the WEC design process. The generalized body-modes method, however, is a reduced order, linearized, frequency-domain FSI approach, performed in conjunction with the linear hydrodynamic analysis, with computation times that could realistically be incorporated into the WEC design process. The objective of this study is to verify the generalized body-modes approach in comparison to high-fidelity FSI simulations to accurately predict structural deflections and stress loads in a WEC. Two verification cases are considered, a free-floating barge and a fixed-bottom column. Details for both the generalized body-modes models and FSI models are first provided. Results for each of the models are then compared and discussed. Finally, based on the verification results obtained, future plans for incorporating the generalized body-modes method into the WEC simulation tool, WEC-Sim, and the overall WEC design process are discussed.« less
  • Abstract not provided.
  • This study explores and verifies the generalized body-modes method for evaluating the structural loads on a wave energy converter (WEC). Historically, WEC design methodologies have focused primarily on accurately evaluating hydrodynamic loads, while methodologies for evaluating structural loads have yet to be fully considered and incorporated into the WEC design process. As wave energy technologies continue to advance, however, it has become increasingly evident that an accurate evaluation of the structural loads will enable an optimized structural design, as well as the potential utilization of composites and flexible materials, and hence reduce WEC costs. Although there are many computational fluidmore » dynamics, structural analyses and fluid-structure-interaction (FSI) codes available, the application of these codes is typically too computationally intensive to be practical in the early stages of the WEC design process. The generalized body-modes method, however, is a reduced order, linearized, frequency-domain FSI approach, performed in conjunction with the linear hydrodynamic analysis, with computation times that could realistically be incorporated into the WEC design process.« less
  • Abstract not provided.