• International Journal of High-Rise Buildings
• /
• v.5 no.1
• /
• pp.31-41
• /
• 2016

High-rise buildings are increasingly viewed as having both technical and economic advantages, especially in areas of high population density. Increasingly taller buildings are being built worldwide. Increased heights entail increasing flexibility, which can result in serviceability problems associated with significant displacements and accelerations at higher floors. The purpose of this paper is to present the concept of a versatile vibration control technology (MR dampers with bracings) that can be used in super tall buildings. The proposed technology is shown to be effective, from a serviceability point of view, as well as resulting in dramatically reduced design wind loads, thus creating more resilient and sustainable buildings.

• Transactions on Electrical and Electronic Materials
• /
• v.18 no.2
• /
• pp.111-118
• /
• 2017

The increased diversity of different types of energy sources requires moving towards smart distribution networks. This paper proposes a probabilistic DG (distributed generation) units planning model to determine technology type, capacity and location of DG units while simultaneously allocating ESS (energy storage systems) based on pre-determined capacities. This problem is studied in a wind integrated power system considering loads, prices and wind power generation uncertainties. A suitable method for DG unit planning will reduce costs and improve reliability concerns. Objective function is a cost function that minimizes DG investment and operational cost, purchased energy costs from upstream networks, the defined cost to reliability index, energy losses and the investment and degradation costs of ESS. Electrical load is a time variable and the model simulates a typical radial network successfully. The proposed model was solved using the DICOPT solver under GAMS optimization software.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.19 no.7
• /
• pp.651-658
• /
• 2009

In this study, computer applied engineering(CAE) techniques are fully used to efficiently conduct structural and dynamic analyses of a huge composite rotor blade using super-element. Computational fluid dynamics(CFD) is used to predict aerodynamic loads of the rotating wind-turbine blade. Structural vibration analysis is conducted based on the non-linear finite element method for composite laminates and multi-body dynamic simulation tools. Various numerical results are presented for comparison and the structural dynamic behaviors of the rotor blade are investigated herein.

• Proceedings of the KIEE Conference
• /
• summer
• /
• pp.627-629
• /
• 2004

V type suspension string sets prevent instabilities from swing motion by the horizontal angle and by wind pressure. These installation conditions are controled mainly 3 items - normal swing angle by horizontal angle of line, unusual swing angle by strong wind, minimum vertical loads. We calculated and analysed that factors for the 765kV transmission line condition. And we were tested swing characteristics of V-string sets in real size test situation. So, we find to installation condition for the V type suspension string sets. This results will be used to design of V type suspension string set and to decision of the installation condition.

• 한국신재생에너지학회:학술대회논문집
• /
• 2007.11a
• /
• pp.331-334
• /
• 2007

Wind turbine is composed by 3 major parts, rotor ass'y, nacelle ass'y and tower. There are two major point in nacelle cover analysis one is nacelle cover itself the other is cover support structure. Both of them are required strength proof with light weight. For the design of structure, the loads are calculated according to GL wind guideline Ed. 2003 and by the commercial F.E. codes,

• Proceedings of the KSME Conference
• /
• 2008.11a
• /
• pp.757-761
• /
• 2008

The aerostat dynamic equation of motion has been built including the tether cable dynamic effects. A numerical program to solve the derived equation of motion has been developed. The dynamic motion of the 32m aerostat has been analyzed under discrete gust and continuous turbulence. The aerostat behaviors under discrete gust which represents a deterministic approach for determining design loads for manned aircraft are solved to verify the effect of aerostat mechanical properties on the aerostat dynamic behavior. Continuous turbulences are simulated for each given altitude, translational mean wind velocity and gust intensity. Dynamic behaviors of the 32m aerostat are simulated for each continuous turbulence conditions. Translational and vertical velocity and pitching behavior and tether reaction force are monitored for each simulation.

• New & Renewable Energy
• /
• v.4 no.3
• /
• pp.45-50
• /
• 2008

GFRP based composite rotor blades were developed for 750 kW & 2 MW wind turbines. The blade sectional geometry was designed to have a general shell-spar and shear web structure. For verifying the structural safety under all relevant extreme loads specified in the GL guidelines, the structural analysis of the rotor blades was performed using commercial FEM codes. The static load carrying capacity, blade tip deflections and natural frequencies were evaluated to satisfy the strength and stability requirements. Full-scale proof tests of rotor blades were carried out with optical fiber sensors for real-time condition monitoring. Finally, the prototype of each rotor blade passed all proof tests for GL certification.

• Wind and Structures
• /
• v.7 no.6
• /
• pp.393-404
• /
• 2004

The design of truss type sign support structures is based on the guidelines provided by the American Association of State Highway and Transportation Officials Standard Specifications for Highway Signs, Luminaries and Traffic Signals and the American Institute of Steel Construction Design Specifications. Using these specifications, the column design strength is normally determined using the effective length approach. This approach does not always accurately address all issues associated with frame stability, including the actual end conditions of the individual members, variations of the loads in the members, and the resulting sidesway buckling for truss type sign support structures. This paper provides insight into the problems with the simplified design approach for determining the effective lengths and discusses different approaches for overcoming these simplifications. A system buckling approach, also known as a rational buckling analysis, is used in this study to determine improved predictions for design strength of truss type sign support structures.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.12 no.4
• /
• pp.649-659
• /
• 1999

본 연구에서는 점탄성감쇠기가 설치된 비비례 감쇠 구조물의 바람에 대한 확률적 응답을 진동수영역에서 구하였다. 복소수 고유치 및 고유백터를 바탕으로 모드중첩법을 이용하여 응답의 RMS 값을 구하고 그것을 근사적인 방법인 모드 변형에너지법에서 얻은 결과와 비교하였다. 또한, 가력 진동수에 따라서 변하는 점탄성감쇠기의 강성 및 감쇠 계수를 상수로 모형화하였을 때의 풍응답 해석 결과의 정확성을 진동수영역에서 검증하였다. 해석결과에 의하면 감쇠기의 진동수 의존 특성은 구조물의 1차 고유 진동수에 의해서 비교적 정확하게 표현되었고, 모드 변형에너지법은 대체로 정확한 결과를 도출하였지만, 가속도 응답을 구할 때에는 다소 큰 오차를 유발하였다.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2004.11a
• /
• pp.53-56
• /
• 2004

Recently, post tension flat plate slab system is widely used for a new slab structural system. Slab-column connections may fail in brittle manner by punching shear. Flat plate slabs have been widely used for gravity load resisting system in buildings. Lateral resistance usually provided by shear walls or moment resisting frames. Since plat plates move together with lateral loading system during earthquake or wind, it is important to evaluate the gravity resistance under a drift experienced by lateral force resisting system during either design earthquake or wind. Thus, this study investigated post tension flat plate slab systems whether they have sufficient strength and deformability to resist gravity loads during specified drift levels. Experimental research was carried out.