• 한국소음진동공학회논문집
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• 제14권8호
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• pp.734-740
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• 2004

In this work, the effect of composite couplings and mass distributions on hub loads of a hingeless rotor in forward flight is investigated. The hingeless composite rotor is idealized as a laminated thin-walled box-beam. The nonclassical effects such as transverse shear and torsion warping are considered In the structural formulation. The nonlinear differential equations of motion are obtained by applying Hamilton’s principle. The blade responses and hub loads are calculated using a finite element formulation both in space and time. The aerodynamic forces acting on the blade are calculated using the quasi-steady strip theory. The theory includes the effects of reversed flow and compressibility. The magnitude of elastic couplings obtained by MSC/NASTRAN is compared with the classical pitch-flap($\delta$$_3$) coupling. It Is observed that the elastic couplings and mass distributions of the blade have a substantial effect on the behavior of $N_{b}$ /rev hub loads. About 40％ hub loads is reduced by tailoring or redistributing the structural properties of the blade.e.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.629-632
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• 2009

The polymeric desiccant rotor is made from the super absorbent polymer by ion modification. The moisture sorption capacity of the super desiccant polymer(SDP) is 4 to 5 times larger than those of common desiccant meterials such as silica gel or zeolite. It is also known that SDP can be regenerated even at the relatively low temperature. To fabricate the desiccant rotor, firstly the SDP was laminated by coating the SDP on polyethylene sheet. Then corrugated and rolled up into a rotor. The diameter, the depth, the dimensions of the corrugated channel, etc. were pre-determined from numerical simulation on the heat and mass transfer in the desiccant rotor. The dehumidification performance was tested in a climate chamber. The relevant tests were carried out at the process air inlet temperature of $32^{\circ}C$, the regeneration air inlet temperature of $60^{\circ}C$ and the inlet dew-point temperature of both the process air and the regeneration air of $18.5^{\circ}C$, when the rotation period is long, the moisture sorption is not effective. In the desiccant rotor developed in this study, the optimum rotation period is found about 350s at the regeneration temperature of $60^{\circ}C$. It was found from further experiments that the optimum rotation tends to decreases as the regeneration temperature increases. Meanwhile, the outlet temperature of the process air deceases monotonically as the rotation period increases.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제23권4호
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• pp.367-380
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• 2019

A 1kW-class horizontal axis wind turbine (HAWT) rotor blade is taken into account to investigate elastic characteristics in 2-D. The elastic blade field is composed of symmetric cross-ply laminated composite material. Blade element momentum theory is applied to obtain the boundary conditions pressuring the blade, and the plane stress elasticity problem is formulated in terms of two displacement parameters with mixed boundary conditions. For the elastic characteristics a fair of differential equations are derived based on the elastic theory. The domain is divided by triangular and rectangular elements due to the complexity of the blade configuration, and a finite element method is developed for the governing equations to search approximate solutions. The results describe that the elastic behavior is deeply influenced by the layered angle of the middle laminate and the stability of the blade can be improved by controlling the layered angle of laminates, which can be evaluated by the mathematical approach.

• Journal of Electrical Engineering and Technology
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• 제6권5호
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• pp.618-625
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• 2011

This paper presents a double excited three degree-of-freedom (3DOF) motor. The proposed 3DOF motor is designed with a laminated structure, making it easy to manufacture. In addition, it has windings on the stator and rotor, and does not require an expensive permanent magnet. We explain the structure, principle of motion, and design of the proposed motor, and perform an analysis of the static characteristics using the two- and three-dimensional finite element methods (3D FEM). The feasibility of 3D FEM analysis is confirmed by comparing the 3D FEM analysis and experimental results for the rolling and pitching motion. We also confirm the occurrence of holding torque in every motion.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.955-957
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• 2002

This paper presents a detailed characteristic of reluctance synchronous motor (RSM) which has a axially laminated anisotropic (ALA) structure of the rotor. First of all, the analysis of a magnetic circuit field between stator and rotor should be achieved in order to predict the performance characteristics of the RSM. For the analysis of a magnetic circuit field, the finite element (FE) analysis is used. The analytical result of the inductance, flux distribution, vector potential and simulation results shows along with the load condition.

• 전기의세계
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• 제24권2호
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• pp.63-70
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• 1975

The solid-iron rotor induction motor is the squirral cage type induction motor with its rotor core consisting of solid iron in stead of a laminated core. The specific feature of this motor are that its structure is simple and firm, and therefore provides the great convenience in its operation and that its starting characteristic are excellent. this study is aimedto derive the equation for theroretical evaluation of the speed-torque characteristics of the motor by use of maxwell's equation. Through the series of test on the speed-torque characteristics of this motor which is experimentally constructed, we have proved the feasibility of the equaiton which is derived theoretically to calculate the torque of the motor. In addition we have obtained its general charastristics experimentally.

• Composites Research
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• 제14권2호
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• pp.50-59
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• 2001

다목적헬리콥터용으로 설계된 복합재 무힌지 로터깃에 대하여 강도저하모델을 활용하여 비행모사 하중스펙트럼에 따라 피로파손 확률분포와 잔여강도 변화거동을 해석하여 피로수명을 예측하였다. 이때 작용하는 피로하중은 실제 헬리콥터 운용상태를 모사하는 무힌지 로터깃의 표준하중스펙트럼인 FELIX 데이터로부터 비행 대 비행 하중스펙트럼을 구성하였고 피로손상이 가장 극심하게 예상되는 깃뿌리 부근의 국부응력스펙트럼은 스킨과 스파의 적층구조해석을 수행함으로써 구하였다.

• Journal of Electrical Engineering and Technology
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• 제10권1호
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• pp.155-164
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• 2015

In this paper, two rotor configurations including different amount of magnet and reluctance parts are presented. The rotors are constituted by means of a flexible hybrid motor structure. Considerable features of the hybrid structure are that the combination of the magnet and reluctance parts can be suitably modified and the mechanical angle (${\beta}$) between the parts can also be varied. Two hybrid rotor configurations have been considered in this study. First, finite element (FE) simulations were carried out and the torque behaviors of the motors were predicted. The average torque ($T_{avg}$) and maximum torque ($T_{max}$) curves were obtained from FE simulations in order to find suitable ${\beta}$. Mathematical model of the motors was formed in terms of a,b,c variables considering the amount of the magnet and reluctance parts on the rotor and simulations were performed. Rotor prototypes, motor drive and drive method were introduced. Torque profiles of the motors were obtained by static torque measurement and loaded tests were also realized. Thus, simulation results were verified by experimental study. There is a good match between predictions and measurements. The proposed motors are operated with electrical $120^{\circ}$ mode as a brushless DC motor (BLDC) and torque versus speed characteristics show a compound DC motor characteristic. The motors can be named as brushless DC compound motors.

• 한국항공우주학회지
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• 제32권7호
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• pp.29-36
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• 2004

본 연구에서는 전진비행시 무힌지 로터 블레이드의 허브하중에 대한 복합재료 연성의 영향을 고찰하였다. 무힌지 복합재료 로터 블레이드를 단일 상자형 보로 모델링 하였으며, 전단 변형 및 비틀림 워핑과 같은 비고전적 효과를 고려하였다. 운동방정식은 해밀턴의 원리를 이용하여 구성하였으며, 로터 블레이드의 공간 및 시간차원에서의 유한요소법을 적용하여 완전평형해석을 수행하였다. 블레이드에 작용하는 공기력은 2 차원 준정상 공기력 이론을 바탕으로 하여 역류 및 압축성 효과를 고려하였다. MSC/NASTRAN을 이용하여 피치 -플랩 및 피치-래그와 같은 탄성 연성의 크기를 구하고, 고전적인 기하학적 연계와 비교하였다. 탄생 연성은 $N_b/rev$ 허브하중의 특성에 적지 않은 영향을 미침을 확인하였다 블레이드 복합재료의 적층각을 적절히 변화시킬 경우 약 10-40%의 허브하중을 감소시킬 수 있음을 보였다.

• 한국안전학회지
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• 제29권5호
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• pp.15-21
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• 2014

The aim of this work is conduct the study on light weight and structural performance improvement of the composite wind power blade. GFRP (Glass Fiber Reinforced Plastic) pre-empted by CFRP(Carbon Fiber Reinforced Plastic), the major material of wind power blade, was identified the superiority of mechanical performance through the tensile and fatigue test. SENT(Single Edge Notched Tension) specimen fracture test was conducted on the specimen that laminated together 2 ply CFRP with 4 ply GFRP through DIC(Digital Image Correlation) analysis. The SENT specimen thickness and $a_0/W$ ratio is 1.45 mm and 0.2, respectively. The fracture test accomplished with displacement control with 0.1 mm/min at the room temperature. The experimental apparatus used for the fracture test consisted of a 50kN universal dynamic tester and CCD camera connected to a personal computer (PC), which was used to record images of the specimen surface. Following data acquisition, the images and load-displacements were transferred to the PC, on which the DIC software was implement. The experiment and DIC analysis results show that CFRP/GFRP laminated composite exhibits improvement of the strength, compared with that of the existing blade material. This study shows the result that the strength of CFRP rotor blade of wind turbine satisfies through the experimental and DIC method.