• Title/Summary/Keyword: tip deflection

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Structural Design of Medium Scale Composite Wind Turbine Blade

  • Kong, Chang-Duk;Kim, Jong-Sik
    • International Journal of Aeronautical and Space Sciences
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    • v.1 no.1
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    • pp.92-102
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    • 2000
  • In this study, the 750kW medium scale composite blade for the horizontal axis wind turbine system was designed and manufactured, and it was tested and evaluated by the specific structural test rig. In the test, it was found that local bucklings at the trailing edge of the blade and excessive deflections at the blade tip were happened. In order to solve these problems, the design of blade structure was modified. After improving the design, the abrupt change of deflection at the blade tip was reduced by smooth variation of the spar thickness and the local buckling was removed by extending the web length. The modified design was analyzed by the FEM, the safety and stability of the blade structure. And Fatigue life over 20 years was confirmed by using S-N linear damage method, Spera's method, etc.

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Structural design and evaluation of a 3MW class wind turbine blade

  • Kim, Bum-Suk
    • Journal of Advanced Marine Engineering and Technology
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    • v.38 no.2
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    • pp.154-161
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    • 2014
  • This research presents results of structural designs and evaluations for 3MW Wind Turbine Blade by FEM analysis. After the GFRP model was designed as a baseline model, failure check by Puck's failure criterion and buckling analysis were accomplished to verify safety of wind turbine blade in the critical design load case. Moreover, applicability of two kinds of carbon spar cap model, was studied by comparing total mass, price and tip deflection to the GFRP model. The results showed that the GFRP model had sufficient structural integrity in the critical design load case, and the carbon spar cap model could be a reasonable solution to reduce weights, tip deflections.

Numerical Analysis of Large Deflections of Cantilever Beams (캔틸레버 보의 과대처짐 해석)

  • Lee, Byoung Koo
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.10 no.1
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    • pp.1-7
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    • 1990
  • A method is developed for solving the elastica of cantilever beam subjected to a tip point load and uniform load. The Bernoulli-Euler differential equation of deflected beam is used. The Runge-Kutta method and the Regula Falsi method are used to perform the integration of the differential eqution and to determine the horizontal deflection, respectively. The horizontal and vertical deflections of the free end, and the free-end rotations are calculated for a range of parameters representing variations in tip point load and uniform load. All results are presented in nondimensional forms. And some typical elastic are also presented.

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Analysis and Control f Contact Mode AFM (접촉모드 AFM의 시스템 분석 및 제어)

  • 정회원;심종엽;권대갑
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.3
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    • pp.99-106
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    • 1998
  • Recently, scientists introduced a new type of microscope capable of investigating nonconducting surfaces in an atomic scale, which is called AFM (Atomic Force Microscope). It was an innovative attempt to overcome the limitation of STM (Scanning Tunnelling Microscope) which has been able to obtain the image of conducting surfaces. Surfaces of samples are imaged with atomic resolution. The AFM is an imaging tool or a profiler with unprecedented 3-D resolution for various surface types. The AFM technology, however, leaves a lot of room for improvement due to its delicate and fragile probing mechanism. One of the room for improvements is gap control between probe tip and sample surface. Distance between probe tip and sample surface must be kept in below one Angtrom in order to measure the sample surface in Angstrom resolution. In this paper, AFM system modeling, experimental system identification and control scheme based on system identification are performed and finally sample surface is measured by home-built AFM with such a control scheme.

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Dynamic Characteristics of Cantilever Pipe Conveying Fluid with Moving Mass Considering Nozzle Angle (노즐 경사각을 고려한 이동질량을 가진 유체이송 외팔 파이프의 동특성 해석)

  • 윤한익;손인수;김현수;조정래
    • Journal of Ocean Engineering and Technology
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    • v.16 no.6
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    • pp.18-24
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    • 2002
  • The vibrational system in this study consists of a cantilever pipe conveying fluid, the moving mass upon it, and an attached tip mass. The equation of motion is derived by using the Lagrange equation. The influences of the velocity and the velocities of fluid flow in the pipe have been studied on the dynamic behavior of a cantilever pipe using a numerical method. While the moving mass moves upon the cantilever pipe, the velocity of fluid flow and the nozzle angle increase; as a result, the tip displacement of the cantilever pipe, conveying fluid, is decreased. After the moving mass passes over the cantilever pipe, the tip displacement of the pipe is influenced by the potential energy of the cantilever pipe and the deflection of the pipe; the effect is the result of the moving mass and gravity. As the velocity of fluid flow and nozzle angle increases, the natural frequency of he system is decreased at the second mode and third mode, but it is increased at the first mode. As the moving mass increases, the natural frequency of the system is decreased at all modes.

The Dynamic Characteristics of Rotating Cantilever Pipe Conveying Fluid (회전하는 유체이송 외팔 파이프의 동특성 해석)

  • 윤한익;손인수
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.13 no.1
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    • pp.26-32
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    • 2003
  • The vibrational system of this study is consisted of a rotating cantilever pipe and the flow in the pipe. The equation of motion is derived by using Lagrange equation. The influences of the rotating angular velocity and the velocities of fluid flow in the pipe have been studied on the dynamic characteristics of a rotating cantilever pipe by numerical method. The tip-amplitude of axial vibration and maximum tip-deflection of axial direction of cantilever pipe are directly proportional to the velocity of fluid and rotating angular velocity of pipe In the steady state. respectively The bending tip-amplitude of cantilever pipe is inversely proportional to the velocity of fluid in the steady state. When the rotating angular velocity is 5 rad/s, the velocity of fluid increase with increasing the natural frequency of axial vibration at second mode and third mode, but the natural frequency axial direction of first mode is decreased. The natural frequency of lateral direction is decreased due to increase of the rotating angular velocity. It identifies that the Influence of velocity of fluid give much variation lower mode of vibration in lateral direction. And the Influence of velocity of fluid give much variation higher mode of vibration in axial direction.

Design and Fabrication of a Micro PZT Cantilever Array Actuator for Applications in Fluidic Systems

  • Kim Hyonse;In Chihyun;Yoon Gilho;Kim Jongwon
    • Journal of Mechanical Science and Technology
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    • v.19 no.8
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    • pp.1544-1553
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    • 2005
  • In this article, a micro cantilever array actuated by PZT films is designed and fabricated for micro fluidic systems. The design features for maximizing tip deflections and minimizing fluid leakage are described. The governing equation of the composite PZT cantilever is derived and the actuating behavior predicted. The calculated value of the tip deflection was 15 ${\mu}m$ at 5 V. The fabrication process from SIMOX (Separation by oxygen ion implantation) wafer is presented in detail with the PZT film deposition process. The PZT films are characterized by investigating the ferroelectric properties, dielectric constant, and dielectric loss. Tip deflections of 12 ${\mu}m$ at 5 V are measured, which agreed well with the predicted value. The 18 ${\mu}l/s$ leakage rate of air was observed at a pressure difference of 1000 Pa. Micro cooler is introduced, and its possible application to micro compressor is discussed.

Experimental Verification of Compressor Blade Aeromechanics (압축기 블레이드 Aeromechanics의 시험적 검증)

  • Choi, Yun Hyuk;Park, Hee Yong;Kim, Jee Soo;Shin, Dong Ick;Choi, Jae Ho;Kim, Yeong Ryeon
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2017.05a
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    • pp.240-244
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    • 2017
  • Experimental verification in the rig test stage for component development is a vital link between the aeromechanical design and structural integrity validation process. Based on this premise, Non-Intrusive Stress Measuring System was adopted on the axial compressor test rig to measure the static and dynamic tip deflection of all blades by using tip-timing sensors. Through analyzing vibration characteristics, we evaluated the vibratory stresses seen on the blades fatigue critical location; detected synchronous resonances which are the source of High Cycle Fatigue (HCF) in blades; presented non-synchronous vibration response by aerodynamic excitation and individual blade mis-tuning patterns.

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Fabrication and Mechanical Properties of Carbon Nanotube Probe for Ultrasmall Force Measurement in Biological Application (생물학적 초미세력 검출을 위한 탄소나노튜브 프로브의 제작 및 기계적 특성 검출)

  • Kwon, Soon-Geun;Park, Hyo-Jun;Lee, Hyung-Woo;Kwak, Yoon-Keun;Kim, Soo-Hyun
    • Journal of the Korean Society for Precision Engineering
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    • v.25 no.5
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    • pp.140-147
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    • 2008
  • In this study, a carbon nanotube probe (CNT probe) is proposed as a mechanical force transducer for the measurement of pico-Newton (pN) order force in biological applications. In order to measure nantube's displacement in the air or liquid environment, the fabrication of a CNT probe with tip-specific loading of fluorescent dyes is performed using tip- specific functionalization of the nanotube and chemical bonding between dyes and nanotube. Also, we experimentally investigated the mechanical properties of the CNT probe using electrostatic actuation and fluorescence microscope measurement. Using fluorescence measurement of the tip deflection according to the applied voltage, we optimized the bending stiffness of the CNT probe, therefore determined the spring constant of the CNT probe. The results show that the spring constant of CNT probes is as small as 1 pN/nm and CNT probes can be used to measure pN order force.

Vibration Analysis of Wedge Type Bar by Ritz Method (Ritz법을 이용한 쐐기형 봉의 진동 해석)

  • Park Sok-Chu
    • Journal of Advanced Marine Engineering and Technology
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    • v.29 no.8
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    • pp.877-882
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    • 2005
  • This paper discusses the lateral vibration of a bar which has its tip free. The uniform bar has a solution by summation of some simple exponential functions But if its shape is not uniform, its solution could be by Bessel's function, or mathematical solution could not be existed. Enen if the solution of Bessel's function exists. as Bessel function is a series function. we must got the solution by numerical method Hereby the author Proposes the ununiform beam solution of the matrix method by Ritz's method. and Proposes a new deflection shape function.