• 제목/요약/키워드: Blade Force

검색결과 272건 처리시간 0.026초

Process Modeling of Flexible Robotic Grinding

  • Wang, Jianjun;Sun, Yunquan;Gan, zhongxue;Kazerounian, Kazem
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2003년도 ICCAS
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    • pp.700-705
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    • 2003
  • In this paper, an extended process model is proposed for the application of flexible belt grinding equipment as utilized in robotic grinding. The analytical and experimental results corresponding to grinding force, material removal rate (MRR) and contact area in the robotic grinding shows the difference between the conventional grinding and the flexible robotic grinding. The process model representing the relationship between the material removal and the normal force acting at the contact area has been applied to robotic programming and control. The application of the developed model in blade grinding demonstrates the effectiveness of proposed process model.

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비선형 구속 와류 보정법을 이용한 수평축 풍력 발전기의 공력 해석 (Aerodynamic Analysis of Horizontal Axis Wind Turbines using Nonlinear Bound Vortex Correction Method)

  • 김호건;이승민;이수갑
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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    • pp.307-310
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    • 2008
  • Nonlinear Vortex Strength Correction Method is developed for improvement of vortex lattice method which can't calculate the separated flow conditions and the viscous effect. In this method, the vortex strength on the blade surface is determined by matching the lift force from vortex lattice method with the lift force from aerodynamic coefficients table as the same circulation is added to or subtracted from all chord wise vortices. For considering the nonlinearities due to the neighboring blade sections, sophisticated Newton-Rapson algorithm is applied. The validation of this method was done by comparing the simulations with the measurements on the NREL Phase-VI horizontal axis wind turbine(HAWT) in the NASA Ames wind tunnel under uniform conditions. This method gives good agreements with experiments in most cases.

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원심분리기용 스크류의 블레이드 및 원공형상변화에 따른 응력 및 진동해석 (Stress and Vibration Analysis with respect to the change of the Shape of Screw Blade and the Hole for Centrifuge)

  • 한근조;이성욱;심재준;한동섭;안찬우;서용권;김태형
    • 한국정밀공학회지
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    • 제20권9호
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    • pp.118-125
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    • 2003
  • In this study, we carried out the finite element analysis for the screw of centrifuge that is the weakest part of the centrifuge for sewage management. Centrifugal force caused by rotation with velocity of 4000rpm was applied at the screw. Structural analysis was done with respect to the change of the ratio of blade pitch($R_P$), shaft diameter($R_D$) and extended hole($R_E$). When the area of circular hole is equal to that of extended holes, maximum equivalent stresses in the screw with circular and extended circular hole were compared. And then natural frequency analysis was executed for the same model. Three mode shapes were used to explain the vibration characteristics of each screw. Convergence study was accomplished fur more accurate results.

프리하든 금형강의 정밀 홀 가공에 관한 연구 (A Study on the Precision Hole Machiningof Pre Hardened Mould Steel)

  • 이승철;조규재;박종남
    • 한국기계가공학회지
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    • 제11권2호
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    • pp.98-104
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    • 2012
  • In this paper, precision processing is carried out for the pre hardened steel(HRC 54), which is one of injection mould materials. Processing characteristics are estimated according to the number of tool cutting blade and roundness is observed by the 3-Dimensional measuring machine. The surface roughness affected by the wire electric discharge machining are measured. Cutting component force of STAVOX is the highest in condition of 2F processing because load per a blade of cutting tool is high. Especially, the difference in Fz is over 20N by cutting load. The slower spindle rotation speed and tool feed rate are, the better cutting component force is. The roundness of hole processed in condition of 4F is good because feed rate is able to be fast. When rotation speed is increased, the surface roughness is decreased. The surface roughness acquired in condition of 2F processing is higher about 50% than 4F processing.

터빈 블레이드의 형단조 금형설계의 자동화에 관한 연구 (Development of Die Design System for Turbine Blade Forging)

  • 최병욱;조종래;왕지석;김동권;김동영
    • 소성∙가공
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    • 제8권6호
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    • pp.569-575
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    • 1999
  • Computer programs have been developed to design the forging dies of turbine and compressor blades. The design of forging dies is based the side force and the filling of die cavity. In this study, slab method has been applied to simulate forging processes numerically. the program composed of Visual Basic also provides the informations of mean stress, total forging load, distribution of temperature, position of neutral line, total volume and volume of flash in the final stage to users. The preform position is predicted by the reverse slab method. The program has been successfully applied to various types of turbine blades.

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가변피치 프로펠러의 축기전력 특성에 관한 연구 - 세계로호를 중심으로 - (A Study on the Characteristics of Shaft Electric Motive Force of Controllable Pitch Propeller - Focusing on the M/V Segero -)

  • 박경민;임명환;최상범;안병원
    • 해양환경안전학회지
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    • 제28권1호
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    • pp.135-140
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    • 2022
  • 대부분의 기계는 여러 종류의 금속으로 구성된다. 특히 선박의 축계는 프로펠러 날개의 황동과 스테인리스로 된 축으로 이루어져 있다. 이 이종금속이 바닷물의 전해액에 들어가면 볼타 전지를 이루고, 기전력이 발생된다. 이 기전력은 축계를 받치고 있는 베어링과 축을 전기부식 시키는 원인이 된다. 선박에서는 이 부식을 막기 위해 선박에서는 축 접지 시스템을 설치하여 운용하고 있다. 본 연구는 가변피치 프로펠러의 축기전력을 측정하기 위하여 추진축의 전압과 주기관의 회전수를 동시에 측정하였다. 측정장치는 내셔널인스트루먼트사의 24bit A/D컨버터를 사용하여 측정하였고, 프로그램은 LabVIEW를 사용하였다. 주기관의 회전수와 축기전력의 발생, 블레이드 각도에 따른 기전력과, 배의 항해 방향에 따른 축기전력을 측정하고 분석하였다.

AFM을 이용한 발전소용 저압 터빈 블레이드의 파손해석에 관한 연구 (A Study on Failure Analysis of Low Pressure Turbine Blade in Nuclear Plant using AFM)

  • 홍순혁;최우성;문성준;조석수;주원식
    • 한국정밀공학회지
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    • 제18권10호
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    • pp.61-68
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    • 2001
  • Turbine blade in nuclear plant is subject to cyclic bending fatigue by high steam pressure. Especially, fatigue fracture is caused by low stress below yielding stress. Photograph by SEM doesn't have striation but photograph by AFM has striation on the fatigue fractured surface of 12% Cr steel used in turbine blade. Surface roughness $R_q$ has the linear relation with respect to stress intensity factor range ΔK and is increased linearly according to load amplitude $\textit{\Delta}P$. In this study loading condition applied to turbine blade is predicted by the relation between the gradient of $R_q$ to $\textit{\Delta}K$ and load amplitude $\textit{\Delta}P$.

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대형선박의 추진기 진동 모드 특성 (Vibration mode characteristics on a propeller in very large vessel)

  • 김재홍;조대승;한성용
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2002년도 춘계학술대회논문집
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    • pp.955-962
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    • 2002
  • According to the trends of construction of large size vessel with high power, the natural frequencies of the bending modes of propeller blades have been lower than the past. Therefore, it is expected that the noise and vibration problems of the marine propeller are frequently occurred. As main issue of the propeller noise and vibration problem, the cavitation noise and singing noise due to the flow induced excitation of the bending modes of propeller blade in the high frequency range has been studied by the hydrodynamic researchers in the view point of the excitation force reduction. In this paper, the vibration mode characteristics of propeller with a large diameter in very large vessel are investigated by the vibration analysis of the finite element method using MSC/Nastran and the vibration measurement by the impact test on the propeller blade. According to the results, the natural frequencies of various blade bending modes in water entrained condition could be estimated from the natural frequencies taken by the measurement and free vibration analysis in the dry condition, and it could be estimated how the high frequency noise such as singing is generated from the blade bending modes.

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Vibration control of small horizontal axis wind turbine blade with shape memory alloy

  • Mouleeswaran, Senthil Kumar;Mani, Yuvaraja;Keerthivasan, P.;Veeraragu, Jagadeesh
    • Smart Structures and Systems
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    • 제21권3호
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    • pp.257-262
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    • 2018
  • Vibrational problems in the domestic Small Horizontal Axis Wind Turbines (SHAWT) are due to flap wise vibrations caused by varying wind velocities acting perpendicular to its blade surface. It has been reported that monitoring the structural health of the turbine blades requires special attention as they are key elements of a wind power generation, and account for 15-20% of the total turbine cost. If this vibration problem is taken care, the SHAWT can be made as commercial success. In this work, Shape Memory Alloy (SMA) wires made of Nitinol (Ni-Ti) alloys are embedded into the Glass Fibre Reinforced Polymer (GFRP) wind turbine blade in order to reduce the flapwise vibrations. Experimental study of Nitinol (Ni-Ti) wire characteristics has been done and relationship between different parameters like current, displacement, time and temperature has been established. When the wind turbine blades are subjected to varying wind velocity, flapwise vibration occurs which has to be controlled continuously, otherwise the blade will be damaged due to the resonance. Therefore, in order to control these flapwise vibrations actively, a non-linear current controller unit was developed and fabricated, which provides actuation force required for active vibration control in smart blade. Experimental analysis was performed on conventional GFRP and smart blade, depicted a 20% increase in natural frequency and 20% reduction in amplitude of vibration. With addition of active vibration control unit, the smart blade showed 61% reduction in amplitude of vibration.