• 한국신재생에너지학회:학술대회논문집
• /
• 2005.06a
• /
• pp.68-71
• /
• 2005

In the case of wind turbine design, Optimization of tower structure is very important because tower generally takes about $20\%$ of overall turbine cost. In this paper, we calculated wind loads considering vortex shedding, and optimized tower flange using the calculation results. For optimization, we used FEM to analyze structural strength of the flange and blade momentum theory to calculate wind loads.

• Transactions of Materials Processing
• /
• v.21 no.7
• /
• pp.412-419
• /
• 2012

The ingot-breakdown scheme of a tower flange material (low-alloy steel) for offshore wind turbine was investigated using finite element (FE) simulations and experimental analyses. Based on compression test results of the low-alloy steel, a deformation processing map was generated using the superposition approach between the dynamic materials model (DMM) and Ziegler's instability criterion. The deformation processing map allowed determination of the optimum process conditions for the tower flange material. Within the FE simulations of the ingot breakdown process, the Cockcroft-Latham criterion, which considers ductile fracture, was used to predict the possibility of forming defects during the hot working process. In general, the critical value for the ductile fracture of steel is 0.74. During the ingot-breakdown under optimum process conditions, the actual tower flange forgings exhibited a relatively uniform shape without any forming defects.

• 한국신재생에너지학회:학술대회논문집
• /
• 2006.06a
• /
• pp.304-307
• /
• 2006

Recently, as the global warming by fossil fuels and the steep rise of the oil price become social issues, the interest for renewable energy producing system is increasing rapidly. Among these, the wind turbine is most highlighted because of its economic competitiveness. The tower is one of the main components of wind turbine, which occupying about 20% of overall turbine costs. The tower access door located to base part of the tower, is used to enter the tower. This is the main structural weak points because of door hole, weldment, etc. And so are the weldments between the cans and the flanges. In this study, for the top flange part of the tower, by FEM using ANSYS, we retrieved the maximum von Mises stress on that and carried out fatigue analysis using stresses at such weak points.

• 한국신재생에너지학회:학술대회논문집
• /
• 2007.06a
• /
• pp.391-394
• /
• 2007

The foundation insert is a tubular steel section which is embedded into the concrete of the foundation. The tower base section of the wind turbine is mounted on it. It has a top flange (L type) protruding far enough above the concrete to allow bolts to be inserted from underneath. The load is transmitted to the concrete at the base of the section through a T shaped flange. It has many holes for the reinforcements and the cables. The reinforcements of the concrete foundation run through the insert via a series of holes to bind the inner section to the outer section. Holes are provided for the power and communications cabling. The design follows normal European wind turbine practice, based on GL 2003 and Eurocode regulations.

• Wind and Structures
• /
• v.21 no.6
• /
• pp.709-726
• /
• 2015

In this study, a novel vision-based bolt-loosening monitoring technique is proposed for bolted joints connecting tubular steel segments of the wind turbine tower (WTT) structure. Firstly, a bolt-loosening detection algorithm based on image processing techniques is developed. The algorithm consists of five steps: image acquisition, segmentation of each nut, line detection of each nut, nut angle estimation, and bolt-loosening detection. Secondly, experimental tests are conducted on a lab-scale bolted joint model under various bolt-loosening scenarios. The bolted joint model, which is consisted of a ring flange and 32 sets of bolt and nut, is used for simulating the real bolted joint connecting steel tower segments in the WTT. Finally, the feasibility of the proposed vision-based technique is evaluated by bolt-loosening monitoring in the lab-scale bolted joint model.

• Journal of Wind Energy
• /
• v.15 no.2
• /
• pp.23-36
• /
• 2024

In this study, a health monitoring system was developed for the two most vulnerable parts of a wind tower support structure: the connection between steel towers (L-Flange) and the concrete foundation-steel tower connection. To select assessment parameters for health monitoring, detailed FEM analysis was conducted using the ABAQUS program. Additionally, a testbed was established near the Jeju Woljeongri wind turbine farm to evaluate the applicability of measurement data by installing sensors. Through computational analysis and relevant criteria review, we defined limits for measurement parameters by vulnerable section. We categorized the structural safety evaluation into four stages: normal, caution, warning, and danger, and selected management criteria for each stage. From this, an algorithm to evaluate safety was developed, and a visualized monitoring platform based on the established critical parts monitoring system was developed.

• Proceedings of the KSR Conference
• /
• 2006.11b
• /
• pp.565-580
• /
• 2006

Set in constant increase and period current of lively technical development of railroad use and construction of cable stayed bridge railway bridge, one of bridge form of most suitable that think side police officer and the material enemy of bridge that use long rail, is increasing laying stress on the foreign countries. Main tower fixing department of this cable stayed bridge is consisted of main tower flange that support bearing plate, bay ring plate bearing plate, support end rib and diaphragm etc, as stress transmission mechanic that tensility of cable socket into normal force of main tower, and is used this time. These structural elements is very complex the structure and direction of load delivered from socket specially calbe particularly be different, and need FEM analysis that use Thick Shell element for suitable arrangement of mutual stress flowing grasping and absence that follow hereupon because all of the each support plate angle that suport this differ.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2010.04a
• /
• pp.200-206
• /
• 2010

본 논문은 풍력발전 시스템의 하부 지지 구조물인 타워의 플랜지 연결부 설계 평가를 위한 플랜지 모델건전성 평가 기법에 대해 다룬다. 일반적으로 풍력발전 시스템 타워의 연결부는 Ring-형 플랜지의 형태를 가지고 있다. 이러한 ring-형 플랜지에 대한 설계 기준 및 방법은 풍력 발전 시스템 기술기준 등 에 명시되어있다. 이러한 설계 기준을 따르는 플랜지 연결부에 대해 구조 및 체결 볼트의 건전성 평가를 위해 하중평가 전용 프로그램인 GH-Bladed 3.8를 통해 생성된 하중 데이터를 유한요소 범용 프로그램인 Ansys 12.0에 접목하여 구조해석을 수행 하였다. 해석 방법은 풍력발전시스템의 타워를 셸 요소로 모델링하여 계산한 해석 결과를 플랜지 모델의 경계면에 적용 시켜 해석하는 submodeling 기법과 타워를 빔의 형태로 단순화 화여 계산한 거동 결과를 플랜지 모델에 적용하는 기법을 사용 하였다. 이 두 가지의 해석 기법으로 도출된 결과의 비교를 통하여 해석 결과 신뢰성을 평가하고 효율적이고 합리적인 방법을 제시하고자 하였다.

• Journal of Korean Society of Forest Science
• /
• v.97 no.1
• /
• pp.61-70
• /
• 2008

This study was conducted to develop a mobile tower-yarder with tractor for agriculture and forestry that is the efficient yarder in steep terrains, thinning operation and small scale logging operation. It was designed and manufactured that the power source of tower-yarder is equiped three hydraulic pump connected to PTO of tractor, and three hydraulic pump is used to operate the four motor for drum, the cylinder for clutch of interlocker, the cylinder for tower expanding and the out-rigger cylinder. It was to adopt the running skyline system and the inter-lock function, and to equip the double capstan drum, the storage drum and the clutch for interlock in the development of tower-yarder. It was to develop the tower-yarder which the winch torque of double-capstan drum, the traction force of double-capstan drum, the number of rotation of double-capstan drum and the line speed is $191kg{\cdot}m$, 1,910 kgf, 220.5 rpm and 138.5 m/min, respectively. And it was known that the optimum flange diameter of the main and haulback storage drum is about 360 mm and about 460 mm in order to storage the main line length of 250m and the haulback line length of 450 m. The carriage was made to adopt the running skyline system and to equip the lock function in order to the convenience of chocking and the fall down preventing of tree. It was provided to develop the wire remote controller for the inter-lock function, the convenience of control and the efficiency of yarding. In development process, this tower-yarder was attached the 3-point linkage hitch equipment and the tire wheel for the traction and moving of tower-yarder. Also, it was equipped that the out-rigger and the guy line in order to raise the safety and efficiency of yarding of tower-yarder.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
• /
• v.55
• /
• pp.265-290
• /
• 2012

CEPA (Comprehensive Economic Partnership Agreement) between India and Korea may vitalize Korean economy more and more. Currently most of Korean firms have entered into manufacturing industries like electronics and automobiles. But only a few Korean companies are trying to penetrate into Indian green industry so this paper suggest how to enter into Indian green industry, especially renewable energy sectors. First, Exporting main shaft, tower-flange and polysilicon products can be considered, as a first step of entry mode. Second, entry mode based on contract like technology licensing, strategic alliance and joint venture establishment can be also one of options. For example, Korean solar energy industry which show more competitiveness than that of Indians should try to make technological licensing on PV modules. In addition to this, they should also try to make joint ventures with right Indian partners and build up 'Solar City' nearby regions like Gurgaon in India where many Korean firms are located. Korean shipbuilding firms like Hyundai Engineering which keep on developing wind turbo engines can also try to make strategic alliance with Indian firms like Suzlon which has strong competitiveness. After that, they should explore Korean and Indian wind sector markets together. Third, brownfield investment can be last and final option as a entry mode as we consider the peculiar characteristics of renewable energy industry. Lastly, Korean government which are rush to indulge into green business should formulate more proper and realistic policies to give big incentives the concerned firms which are trying to open international green market so government should make Korean green firms not to lose good market opportunities related to green industry like renewable energy sectors. Renewable energy sectors are basically regarded as infrastructures so close contact to Indian central government as well as state government will be also required.