부유식 풍력-파력발전 플랫폼과 탑재된 파력발전기와의 단방향 연성 운동 해석

이혜빈(Hyebin Lee),배윤혁(Yoon Hyeok Bae),조일형(Il-Hyoung Cho) 한국해양공학회 2016 韓國海洋工學會誌 Vol.30 No.2

In this study, a six degree-of-freedom motion analysis of a wind-wave hybrid platform equipped with numerous wave energy converters (WECs) was carried out. To examine the effect of the WECs on the platform, an analysis of one-way coupling was carried out, which only considered the power take-off (PTO) damping of the static WECs on the platform. The equation of motion of a floating platform with mooring lines in the time domain was established, and the responses of the one-way coupled platform were then compared with the case of a platform without any coupling effects from the WECs. The hydrodynamic coefficients and wave exciting forces were obtained from the 3D diffraction/radiation pre-processor code WAMIT based on the boundary element method. Then, an analysis of the dynamic responses of the floating platform with or without the WEC effect in the time domain was carried out. All of the dynamics of a floating platform with multiple wind turbines were obtained by coupling FAST and CHARM3D in the time domain, which was further extended to include additional coupled dynamics for multiple turbines. The analysis showed that the PTO damping effect on platform motions was negligible, but coupled effects between multiple WECs and the platform may differentiate the heave, roll, and pitch platform motions from the one without any effects induced by WECs.

15 MW급 부유식 해상풍력발전시스템 반잠수식 플랫폼의 운용 조건 중 응답 특성 비교 연구

안현정,하윤진,박세완,김경환 한국풍력에너지학회 2022 풍력에너지저널 Vol.13 No.4

In this study, the response characteristics of two semi-submersible platforms with an IEA 15 MW reference wind turbine are compared. The nacelle acceleration, platform motion and generator power of FOWT applying a VolturnUS-S platform developed by the University of Maine and PentaSemi platform developed by the Korea Research Institute of Ships and Ocean Engineering are compared in operational conditions. Numerical simulations are performed based on the marine environmental conditions of the U.S east coast. In the FOWT to which the PentaSemi platform is applied, the nacelle acceleration and platform pitch angle are rather high, but the results of both platforms satisfied the design criteria at all operating wind speeds. The platform yaw angle of PentaSemi platform to which a yaw control catenary mooring system is applied is significantly smaller than the platform yaw angle of VolturnUS-S. Also, despite the relatively large nacelle acceleration and platform pitch angle, the generator power is higher on the PentaSemi platform. This means that the generator power dominates the control system rather than the nacelle and platform motion.

인장각형 부유식 해상풍력발전시스템의 하부 플랫폼 설계 및 운송⸳설치 관련 특성 고찰

안현정,하윤진,박지용,김경환 한국풍력에너지학회 2023 풍력에너지저널 Vol.14 No.4

In this study, research and empirical cases of floating offshore wind turbine systems with a tension-leg platform are investigated, and hydrodynamic and structural characteristics according to platform shapes and characteristics during transportation and installation are confirmed. Most platforms are composed of pontoons or corner columns, and these are mainly located below the waterline to minimize the impact of breaking waves and supplement the lack of buoyancy of the center column. These pontoons and corner columns are designed with a simple shape to reduce manufacturing and assembly costs, and some platforms additionally have reinforcements such as braces to improve structural strength. Most of the systems are assembled in the yard and then moved by tugboat and installed, and some platforms have been developed with a dedicated barge for simultaneous assembly, transportation and installation. In this study, we intend to secure the basic data necessary for the design, transportation, and installation procedures of floating offshore wind turbine systems with a tension-leg platform.

Vibration Isolation of Extended Ultra-high Acceleration Macro-micro Motion Platform Considering Floating Stator Stage

Lufan Zhang,Xue-li Li,Jiwen Fang,Yunhao Lv,Bing Ma,Jun Wu,Hu Li 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.20 No.8

It is a limitation for rapid development of microelectronics manufacturing industry to hardly overcome the acceleration limitation of macro–micro motion platform. The paper presents an extended ultra-high acceleration macro–micro motion platform to investigate breakthrough of acceleration limitation with driving modes “macro + micro + macro” (MMM). In the proposed platform, the number of the pair of VCMs was defined as n. Under ultra-high acceleration, floating stator stage is suggested to isolate the vibration and obtain superior performance of the platform. Its theoretical analyses including natural frequency analysis, transient response analysis and frequency response analysis are performed to verify vibration isolation of floating stator stage applied in the extended ultra-high acceleration macro–micro motion platform. The change trends and sensitivities of related objective functions incorporating vibration transmissibility, settling time and the maximum stroke of stator’s motion are explored with their related parameters, and their multi-objective optimization designs are carried out to achieve superior performances of different extended platforms. Moreover, one case is performed when n = 1. Its theoretical analyses, change trends and sensitivities are investigated. The superior performance of the platform is obtained to realize vibration isolation by multi-objective optimization. And its experiment of vibration isolation is also testified finally. The results provide a theoretical and technical basis on microelectronics manufacturing equipment upgrading and manufacturing rapid development.

Hydrodynamic response of alternative floating substructures for spar-type offshore wind turbines

Wang, Baowei,Rahmdel, Sajad,Han, Changwan,Jung, Seungbin,Park, Seonghun Techno-Press 2014 Wind and Structures, An International Journal (WAS Vol.18 No.3

Hydrodynamic analyses of classic and truss spar platforms for floating offshore wind turbines (FOWTs) were performed in the frequency domain, by considering coupling effects of the structure and its mooring system. Based on the Morison equation and Diffraction theory, different wave loads over various frequency ranges and underlying hydrodynamic equations were calculated. Then, Response Amplitude Operators (RAOs) of 6 DOF motions were obtained through the coupled hydrodynamic frequency domain analysis of classic and truss spar-type FOWTs. Truss spar platform had better heave motion performance and less weight than classic spar, while the hydrostatic stability did not show much difference between the two spar platforms.

부유식 복합 재생에너지 플랫폼 계류선의 효과적 배치에 관한 연구

정준모(Joonmo Choung),전기영(Gi-Young Jeon),김유일(Yooil Kim) 한국해양공학회 2013 韓國海洋工學會誌 Vol.27 No.4

This paper presents the conceptual design procedure for the taut?leg mooring lines of a floating?type combined renewable energy platform. The basic configuration of the platform is determined based on an understanding of floating offshore plants. The main dimensions and mass distribution are determined based on a hydrostatic calculation. To identify the motion history of the floating platform and the tension history of the mooring lines, a hydrodynamic analysis is executed using Ansys.Aqwa. This helps in the selection of the best configuration for the mooring system such as the number of mooring lines, wire types, anchored positions, etc. In addition, the fatigue life of the mooring lines can be predicted from the tension history using the rain?flow cycle counting method.

Hydrodynamic response of alternative floating substructures for spar-type offshore wind turbines

Baowei Wang,RAHMDELSAJAD,정승빈,한창완,박성훈 한국풍공학회 2014 한국풍공학회지 Vol.18 No.3

Hydrodynamic analyses of classic and truss spar platforms for floating offshore wind turbines (FOWTs) were performed in the frequency domain, by considering coupling effects of the structure and its mooring system. Based on the Morison equation and Diffraction theory, different wave loads over various frequency ranges and underlying hydrodynamic equations were calculated. Then, Response Amplitude Operators (RAOs) of 6 DOF motions were obtained through the coupled hydrodynamic frequency domain analysis of classic and truss spar-type FOWTs. Truss spar platform had better heave motion performance and less weight than classic spar, while the hydrostatic stability did not show much difference between the two spar platforms.

Fatigue Design of Mooring Lines of Floating Type Combined Renewable Energy Platforms

Choung, Joon-Mo,Jeon, Sang-Ik,Lee, Min-Seong Korean Society of Ocean Engineers 2011 International journal of ocean system engineering Vol.1 No.3

This paper presents the concept design procedure of a floating-type combined renewable energy platform based on hydrodynamic analyses and is focused on the fatigue design of taut-type mooring lines of the platform. Two types of combined renewable energy platforms are considered: a combination of wind turbine, wave turbine and photovoltaic energy plant and a combination of wind turbine, current turbine and photovoltaic energy plant. The basic configurations are conceptually determined from the understanding of floating offshore plants, while the main dimensions have been determined based on a hydrostatic calculation. Fully coupled hydrodynamic analyses have been carried out to identify the motion characteristics of the floating body and the tension histories of the mooring lines. The tension history is used for the fatigue life prediction based on the rain-flow cycle counting method. For the fatigue life prediction, tension life curves from API and the Palmgren-Miner rule are employed.

부유식 해양구조물의 플로트오버 설치용 LMU 최적설계

김현석,박병재,성홍근,이강수 한국전산구조공학회 2021 한국전산구조공학회논문집 Vol.34 No.1

A Leg Mating Unit (LMU) is a device utilized during the float-over installation of offshore structures that include hyperelastic pads and mating part. The hyperelastic pads absorb the loads, whereas the mating part works as guidance between topside and supporting structures during the mating sequence of float-over installation. In this study, the design optimization of an LMU for the float-over installation of floating-type offshore structures is conducted to enhance the performance and to satisfy the requirements defined by classification society regulations. The initial dimensions of the LMU are referred to the dimensions of those used in fixed-type float-over installation because only the location and the number of LMUs are known. The two-parameter Mooney–Rivlin model is adopted to describe the hyperelastic pads under given material parameters. Geometric variables, such as the thickness, height, and width of members, as well as configuration variables, such as the angle and number of members, are defined as design variables and are parameterized. A sampling-based design sensitivity analysis based on latin hypercube sampling method is performed to filter the important design variables. The design optimization problem is formulated to minimize the total mass of the LMU under maximum von Mises stress and reaction force constraints. LMU(Leg Mating Unit)는 해양구조물의 플로트오버 실치에서 활용되는 장비 중 하나로 충격을 흡수하는 부분과 결합부로 구성된다. 본 연구에서는 최적설계를 통해 부유식 해양구조물의 플로트오버 설치용 LMU의 성능을 개선하여 설계 요구 조건을 만족하는 설계를 개발하였다. 초기설계는 고정식 해양구조물의 플로트오버 설치용으로 개발된 것의 제원을 참조하였으며, 초탄성재료의 거동을 표현하기 위해 Mooney-Rivlin 모델을 활용하였다. 설계민감도해석 결과를 바탕으로 중요도에 따라 설계 변수들을 선별하였고, 진화 알고리듬 기반 최적설계를 수행하였다. 최적설계 문제에서 목적함수는 LMU의 중량이며, 제약 조건은 LMU에 작용하는 최대 폰-미세스 응력과 LMU의 성능을 평가할 수 있는 반발력이다.

콘크리트 구조물 기반 플로팅 플랫폼 연결에 관한 연구

투멩자르갈,윤대근 해양환경안전학회 2013 해양환경안전학회지 Vol.19 No.1

본 연구는 다양한 기상변화에 따른 안전을 확보하기 위한 해상에서의 플로팅 플랫폼의 연결에 대하여 연구하였다. 본 연구의 목적은 다양한 해상변화가 일어나는 연안역에 설치되는 플로팅 구조물에 관한 문헌 조사를 실시한 후, 콘크리트 구조물 연결하는 모델을 제시하는 것이다. 본 연구에서는 플로팅 구조의 개념, 기존의 모델, 설계적 평가를 포함한 콘크리트 구조물 기반 플로팅 플랫폼을 기술하였고, Rigid Pontoon Connector를 국내 연안역에 적합한 모델로 제안하였다. 연구의 결과로서, 리기드 폰툰 커넥터 디자인은 (Rigid Pontoon Connector) 안정적으로 플로팅 플랫폼의 연결을 구축할 수 있는 매우 효율적이고 실용적인 솔루션으로 분석되었다. This study is about the connector of the floating platform in order to ensure safety due to various climate changes. The purpose of this study is to recommend the connector model of floating platform based on concrete structures after reviewing the literatures related in establishing floating structure in case of various climate changes in domestic coast. This study introduces the concept generation, existing model, detailed design and evaluation including current and future development of the technologies of marina floating platform connector based on concrete structures. The results from the research show that the analysed connector design (Rigid Pontoon Connector) provides a highly efficient and practical solution to facilitate connection of stable floating platform.