• 제목/요약/키워드: Mechanical Engineers

검색결과 28,717건 처리시간 0.034초

속도변환기법을 이용한 기계시스템의 역동학적 해석 (Inverse Dynamic Analysis of Mechanical Systems Using the Velocity Transformation Technique)

  • 이병훈;양진생;전우성
    • 대한기계학회논문집A
    • /
    • 제20권12호
    • /
    • pp.3741-3747
    • /
    • 1996
  • This paper presents a method for the inverse dynamic anlaysis of mechanical systems. Actuating forces(or torques) depending on the driving constraints are analyzed in the relative coordinate space using the velocity transformation technique. A systematic method to compose the inverse velocity transformation matrix, which is used to determine the joint reaction forces, is proposed. Two examples are taken to verify the method developed here.

An Education Model of a Nano-Positioning System for Mechanical Engineers

  • Lee Dong-Yeon;Gweon Dae-Gab
    • Journal of Mechanical Science and Technology
    • /
    • 제20권10호
    • /
    • pp.1702-1715
    • /
    • 2006
  • The increasing use of nano-positioners in a wide variety of laboratory and industrial applications has created a need for nano-mechatronics education in all engineering disciplines. The subject of nano-mechatronics is broad and interdisciplinary. This article focuses on the way nano-mechatronics is taught in department of mechanical engineering at Korea Advanced Institute of Science and Technology (KAIST). As one model of nano-positioning systems, design and experimental methodology is presented in this article. For design phase, the stiffness and resonant frequencies are found analytically and verified by using a commercial finite element analysis program. Next, for experimental phase, various tests are performed to access the performances of the designed nano-positioner, for example, sine-tracking, multi-step response and travel-range check etc. Finally, the definition of 'separation frequency' is described and some comments are discussed.

Cu ECMP 공정에서의 전해질 특성평가 (Characterization of Electrolyte in Electrochemical Mechanical Planarization)

  • 권태영;김인권;박진구
    • 한국전기전자재료학회:학술대회논문집
    • /
    • 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
    • /
    • pp.57-58
    • /
    • 2006
  • Chemical-mechanical planarization (CMP) of Cu has used currently in semiconductor process for multilevel metallization system. This process requires the application of a considerable down-pressure to the sample in the polishing, because porous low-k films used in the Cu-multilevel interconnects of 65nm technology node are often damaged by mechanical process. Also, it make possible to reduce scratches and contaminations of wafer. Electrochemical mechanical planarization (ECMP) is an emerging extension of CMP. In this study, the electrochemical mechanical polisher was manufactured. And the static and dynamic potentiodynamic curve of Cu were measured in KOH based electrolyte and then the suitable potential was found.

  • PDF

창발적 기계설계를 위한 컴퓨터기반 프레임워크 (Framework for Innovative Mechanical Design Using Simulated Emergent Evolution)

  • 이인호;차주헌;김재정
    • 대한기계학회논문집A
    • /
    • 제26권4호
    • /
    • pp.701-710
    • /
    • 2002
  • The framework, described in this paper, involves artificial evolutionary systems that re -produce aimed solutions through a simulated Darwinian evolution process. Through this process the framework designs structures of machines innovatively and emergently especially in the stages of conceptual and basic design. Since the framework simulates the evolution of nature, it inevitably involves processes that converse the natural evolution to the artificial evolution. For the conversion, based on several methods as the building block modeling, Artificial Life, evolutionary computation and the law of natural selection, we propose a series of processes that consists of modeling, evaluation, selection, evolution etc. We have demonstrated the implementation of the framework with the design of multi-step gear systems.

복합응력이 작용하는 균열 배관에 대한 천이 크리프 조건에서의 C(t)-적분 예측 (I) - 탄성-크리프 - (Estimations of the C(t)-Integral in Transient Creep Condition for Pipe with Crack Under Combined Mechanical and Thermal Stress (I) - Elastic-Creep -)

  • 송태광;김윤재
    • 대한기계학회논문집A
    • /
    • 제33권9호
    • /
    • pp.949-956
    • /
    • 2009
  • The C(t)-integral describes amplitude of stress and strain rate field near a tip of stationary crack under transient creep condition. Thus the C(t)-integral is a key parameter for the high-temperature crack assessment. Estimation formulae for C(t)-integral of the cracked component operating under mechanical load alone have been provided for decades. However, high temperature structures usually work under combined mechanical and thermal load. And no investigation has provided quantitative estimates for the C(t)-integral under combined mechanical and thermal load. In this study, 3-dimensional finite element analyses were conducted to calculate the C(t)-integral of elastic-creep material under combined mechanical and thermal load. As a result, redistribution time for the crack under combined mechanical and thermal load is re-defined through FE analyses to quantify the C(t)-integral. Estimates of C(t)-integral using this proposed redistribution time agree well with FE analyses results.

NREL 5MW 풍력터빈의 블레이드 하중 저감을 위한 개별피치제어 (Individual Pitch Control of NREL 5MW Wind Turbine Blade for Load Reduction)

  • 라요한;남윤수;손재훈
    • 대한기계학회논문집A
    • /
    • 제36권11호
    • /
    • pp.1427-1432
    • /
    • 2012
  • 풍력터빈이 점차 대형화 되면서 로터 직경도 점차 커지고 있다. 로터 블레이드는 윈드시어와 타워교란 효과로부터 기계적 하중을 받게 된다. 이러한 기계적 하중은 풍력터빈의 수명을 단축시킨다. 따라서, 풍력터빈의 크기가 커짐에 따라 기계적 하중 완화를 위한 풍력터빈 제어 시스템 설계가 중요하다. 본 논문에서는 로터 블레이드의 기계적 하중 저감을 위한 개별 피치 제어에 대해 소개하고 IPC 성능 검증을 위해 시뮬레이션을 통하여 논의한다.

복합적인 환경인자가 탄소섬유강화 복합재의 기계적 및 열분석 특성에 미치는 영향 (Effects of Combined Environmental Factors on Mechanical and Thermal Analysis Properties of Graphite/Epoxy Composites)

  • 이상진;이종근;윤성호
    • 대한기계학회논문집A
    • /
    • 제26권7호
    • /
    • pp.1416-1425
    • /
    • 2002
  • In this study, the effects of combined environmental factors on mechanical and thermal analysis properties of graphite/epoxy composites were evaluated by the use of an accelerated aging test. Environmental factors such as temperature, moisture. and ultraviolet were considered. A xenon-arc lamp was utilized for ultraviolet light. and exposure times of up to 3000 hours were applied. Several types of specimens - tensile. bending, and shear specimens those are transverse to the fiber direction, and bending specimens those are parallel to the tiber direction - were used to investigate the effects of environmental factors on mechanical properties of the composites. Also, glass transition temperature, storage shear modulus, loss shear modulus, and tan ${\delta}$ were measured as a function of exposure times through a dynamic mechanical analyzer. In addition. a suitable testing method for determining the effect of environmental factors on mechanical properties is suggested by comparing the results from using two different types of strain measuring sensors. Finally, composite surfaces exposed to environmental factors were examined using a scanning electron microscope.

가중함수법에 의한 기계적 체결홀에 존재하는 타원호형 관통균열의 음력확대계수 해석 ( I ) - 가중함수법의 전개 - (Stress Intensity Factor Analysis of Elliptical Arc Through Cracks at Mechanical Fastener Holes by Weight Function Method ( I ) - Development of Weight Function Method -)

  • 허성필;양원호;현철승
    • 대한기계학회논문집A
    • /
    • 제25권10호
    • /
    • pp.1659-1670
    • /
    • 2001
  • It has been reported that cracks at mechanical fastener holes usually nucleate as elliptical corner cracks at the faying surface of the mechanical joints and grow as elliptical arc through cracks after penetrating the opposite surface. The weight function method is an efficient technique to calculate the stress intensity factors fur elliptical cracks using uncracked stress field. In this study the weight function method for three dimensional mixed-mode problem applied to elliptical comer cracks Is modified for elliptical arc through cracks and the stress intensity factors at two surface points of elliptical arc through cracks at mechanical fastener holes are analyzed by the weight function method. This study consists of two parts and in part I , the weight function method for elliptical arc through cracks is developed and verified.

가중함수법에 의한 기계적 체결홀에 존재하는 타원호형: 관통균열의 음력확대계수 해석 (II) - 혼합모드 음력확대계수 해석 - (Stress Intensity Factor Analysis of Elliptical Arc Through Cracks at Mechanical Fastener Holes by Weight Function Method (II) - Mixed-Mode Stress Intensity Factor Analysis -)

  • 허성필;양원호;류명해
    • 대한기계학회논문집A
    • /
    • 제25권10호
    • /
    • pp.1671-1677
    • /
    • 2001
  • Cracks at mechanical fastener holes usually nucleate as elliptical comer cracks at the faying surface of the mechanical joints and grow as elliptical arc through cracks. The weight function method for elliptical arc through cracks at mechanical fastener holes has been developed and verified in the part I of this study. In part H, applying the weight function method, the effects of the amount of clearance on the mixed-mode stress intensity (actors are investigated and the change of crack shape is predicted from the analysis for various crack shapes. The stress intensity factors leer inclined crack are analyzed and critical angle at which mode I stress intensity factor becomes maximum is determined.