Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

Static and Dynamic Structural Analyses for Wave Energy Converterwith Oscillating Body and Connection Arm
Hyun-Sung Kim1,2, Byoung Wan Kim1,2, Yoon-Jin Ha3 and Ji Yong Park3
1Offshore Platform Research Division, Korea Research Institute of Ships and Ocean Engineering (KRISO)

Daejeon, South Korea
2Ship and Offshore Engineering, University of Science and Technology (UST)

Daejeon, South Korea
3Marine Renewable Energy Research Division, Korea Research Institute of Ships and Ocean Engineering (KRISO)

Daejeon, South Korea

energy generation that could use offshore sites and energy resources
including wave, wind, current, and so on is being in limelight. Amongthese marine renewable energy generations, wave energy generation thatutilizes kinetic and potential energies of wave is a proper generation forsites having a higher wave height and long wave period, and have thevarious generation type. There are oscillating body types, oscillatingwater column types, wave overtopping types as energy generation types,
and a large capacity of energy generation is possible depending on ageneration site, characteristic of energy converter, and so on.

ABSTRACT
Studies on renewable energy generation systems are increasing with thegrowth of problems for the existing energy resources such as fossil fuels.
Among the renewable energy generation, the generation in an offshoresite is in limelight due to various energy resources and vast space. Wave
energy generation using the potential and kinetic energies of the wave ispossible to produce large-capacity energy generation considering
installation site and characteristic of a system. In this work, the structural
analyses on the arm structure of oscillating type wave energy converter
are conducted. This type of structure consists of a support structure,
floater, and connection arm connecting the structures. And PTO (PowerTake-Off) device is attached to connection arm and has the role ofmaintaining a generation efficiency by controlling motions of the floater.
As wave-induced force from floater, and PTO damping one are applied
to connection arm, the structure must have structural safety enough forenvironmental conditions. To perform the structural analyses onconnection arm, static and dynamic analyses could be used. Staticanalysis method have the advantage of simple modeling and fastcomputation time rather than dynamic one. But this analysis method
cannot deal with dynamic property of a structure in the time domain.
Thus, in case that needs to consider these dynamic phenomenon, a timedomain dynamic analysis should be performed. In this study, the resultsof two analysis methods are compared and the application of the methodsis considered.

In this study, structural characteristics of wave energy converter withoscillating body and connector arm are assessed by conducting the staticand dynamic analyses, and results of two analysis types are comparedand reviewed. The wave energy converter of oscillating body typeconsists of a floater, connection arm, and support structure. The
connection arm has the role of connecting the floater and support
structure, and of controlling the motion of floater by transferring thedamping force of PTO (Power Take-Off) device connected to connectionarm. Thus, for this connection arm, structural safety enough is requiredin wave and PTO damping load conditions. Floater and PTO device aredesigned in previous studies (Ha et al., 2019; Rho et al., 2019). In caseof connection arm, the shape and properties of the structure are referredfrom the research on wave energy converter, Wavestar (Zurkinden et al.,2013). And, based on these studies, static analysis of the connection arm
has been performed (Kim et al., 2021).
The wave loads on the floater of wave energy converter are calculated
by HOBEM (Higher-Order Boundary Element Method) (Choi et al.,
2000; Hong et al., 2005). By using these wave loads on the structure,structural analyses on connection arm with floater are performed by FEM(Finite Element Method) (Kim et al., 2013; 2015). Static and dynamic
structural analyses on the structure with floater and connection arm areperformed, and structural characteristics of the structure is assessed byreviewing stresses depending on wave periods on the structure. And theresults of static and dynamic analysis methods are compared andreviewed, and the application of the methods is considered.

KEY WORDS: Wave energy converter; static analysis; dynamicanalysis; finite element method.
INTRODUCTION
The researches and developments on various renewable energies areincreasing as the growth of problems on the depletion of existing energy
resources like fossil fuel and environmental pollution. To resolve a
limited generation area, civil complaints, and so on, marine renewable

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