• 제목/요약/키워드: Displacements

검색결과 2,654건 처리시간 0.036초

TLS 변위계측모델을 이용한 장스팬 철골 박스형 거더의 변위 계측 (Displacement Measurement of an Existing Long Span Steel Box-Girder using TLS(Terrestrial Laser Scanning) Displacement measurement Model)

  • 이홍민;박효선;이임평;권윤한
    • 한국방재학회:학술대회논문집
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    • 한국방재학회 2007년도 정기총회 및 학술발표대회
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    • pp.53-56
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    • 2007
  • It was previously introduced a new displacement measuring technique using terrestrial laser scanning (TLS) that remotely samples the surface of an object using laser pulses and generates the three-dimensional (3D) coordinates of numerous points on the surface. In this paper, for an assessment of the capabilities of the measuring technique about existing structures, the field tests for vertical displacement measurement of an existing long span steel box-girder are experimentally carried out. The performance of the technique is evaluated by comparing the displacements obtained from TLS system and displacements directly measured from linear variable displacement transducer (LVDT).

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다층지반 굴착시 토류벽에 작용하는 토압분포 (Earth Pressure Distribution on Retention Walls in the Excavation of Multi -Layered Ground)

  • 이종규;전성곤
    • 한국지반공학회지:지반
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    • 제9권1호
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    • pp.59-68
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    • 1993
  • In deep excavations for creation of underground spaces, it would be difficult to predict earth pressure, especially multilayered ground including rock strata. The earth pressures and displacements on the retention walls are measured by load cell, strain gauge and inclinometer which were installed at struts or anchors at 4 deep excavation sites in Seoul area. In this paper, the measured earth pressure from the struts or anchors are compared with Peck's empirical values, and the coefficient of the earth pressures for each strata and horizontal wall displacement are investigated. The coefficient of earth pressure distribution, a(0.65zka), in the flexible and the rigid walls was about 74% and 88% of Peck's value respecitively. The measured earth pressure distributions for the 4 sites showed about 70%∼80% of Peck's empirical values and the average earth pressure coefficients based on the measured data were 0.3 for the felted layer, 0.23 for the weathered rock and 0.19 for the weak rock. The maximum w리1 displacements were found to be less 0.2% of excavation depth.

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전좌굴을 고려한 복합적층원통셸의 거동해석 (Behavior Analysis of Laminated Composite Cylindrical Shells with Prebuckling)

  • 이종선
    • 한국생산제조학회지
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    • 제9권5호
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    • pp.150-156
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    • 2000
  • The objective of this study is to investigate effects of prebuckling on the buckling of laminated composite cylindrical shells. Axial compression and lateral pressure are considered for laminated composite cylindrical shells with the ratios of length to radius. The shell walls are made of a laminate with several symmetric ply orientations. The study was made using finite difference energy method, utilizing the nonlinear bifurcation branch with nonlinear prebuckling displacements. The results are compared to the buckling loads determined when membrane prebuckling displacements are considered. Review the influence of nonlinear prebuckling for the buckling loads, the difference between the actual and classical buckling loads are increased as the increments with the ratios of length to radius, for which is applied the axial compression, but almost same for the lateral pressure.

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사격시험 및 인체구조해석 (Filing Experiments and Structural Analysis of Human Body)

  • 이세훈;최영진;최의중;체재욱;이영신
    • 대한기계학회논문집A
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    • 제31권7호
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    • pp.764-776
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    • 2007
  • On the human-rifle system, the human body is affected by the firing impact. The firing impact will reduce the firing accuracy and change the initial shooting posture. Therefore the study of biomechanical characteristics using human-rifle modeling and numerical investigation is needed. The musculoskeletal model is developed by finite element method using beam and spar elements. In this study structural analysis has been performed in order to investigate the human body impact by firing of 5.56mm small caliber machine gun. The firing experiments with the standing shooting postures were performed to verify analytical results. The result if this study shows analytical displacements of the human-rifle system and experimental displacements of the real firing. As the results, the analytical displacement and stress of human body are presented.

곡률을 갖는 캔틸레버 IPMC 작동기의 스냅-스루 동적 특성 (Snap-through Dynamics of Curved Cantilever IPMC Actuator)

  • 전진한;박중우;염성원;오일권
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2008년도 추계학술대회논문집
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    • pp.372-373
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    • 2008
  • The snap-through phenomena of the curved IPMC actuators were investigated according to the initial curvature of the actuators. The curved actuators were fabricated by long time thermal treatments. Cantilevered IPMCs have a constant curvature and their initial tip-displacements are 0, 8, and 16mm, respectively. These actuators were tested in terms of f response. AC response, FRF test for evaluating the effect of initial shape. The hysteresis and instant speed of tip point were measured for observation of the snap-through. Present results show that initial deformation strongly affects the snap-through phenomena, resulting in much larger tip-displacements.

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보 변환 기법을 이용한 3차원 부유체의 응답해석 (Response Analysis of 3-dimensional Floating Structure Using Beam Transformation)

  • 김병완;홍사영;경조현;조석규
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2006년도 추계학술대회논문집
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    • pp.809-814
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    • 2006
  • In this paper, the modified direct method employing beam transformation technique is proposed in order to efficiently calculate hydroelastic responses of floating structure. Since the proposed method expresses the displacements of three-dimensional structure with those of transformed beam which leads to small number of equations of motion, the method is numerically efficient compared to the conventional direct method. To verify the efficiency of the proposed method a 500 m-long floating structure under wave loads is considered in numerical example. Displacements, bending moments, torsion moments and shear forces are calculated and computing tine is examined. The results are also compared with those of the conventional direct method.

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Effects of Neutron Spectrum and Cross-section Library on Displacements per Atom (dpa)

  • Park, Duck-Gun;Shimakawa, S.;Nagao, Y.;Kang, Young-Hwan
    • 한국원자력학회:학술대회논문집
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    • 한국원자력학회 1997년도 춘계학술발표회논문집(1)
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    • pp.125-130
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    • 1997
  • Effect of cross-section libraries on displacements per atom (dpa) was investigated under the spectrum which is calculated in the outer and inner of capsule in the JMTR fuel region. The variation of dpa value of iron was calculated by TENJIN2 code using several cross section libraries (ENDFB-lV, JENDL 3.1 and JENDL 3.2). The dependency of input spectrum on total damage (dpa) is more clearly appeared in case or ENDFB-IV in JENDL 3.2 and JENDL 3.1 libraries. The gas production rate calculated by ENDFB-IV library showed slightly larger value than that by JENDL library, and it responded more sensitively in neutron spectrum.

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도수교정의 검사원리 (Examination Principles of Manipulation)

  • 박지환
    • 대한정형도수물리치료학회지
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    • 제1권1호
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    • pp.49-63
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    • 1995
  • Examination at the spine is dependent on assessment of function. At all spine levels a number of general anatomical considerations hold sway which together dictate the format of the evaluation. Because disc lesions are common and generally responsive to treatment, the examination sets out to differentiate between disc lesions and the other sources of pain as well as establishing the particular treatment that will benefit any given displacement. As elsewhere in the body, displacements give rise to certain characteristic symtoms and signs. First, the history is indicative. Second, any loose fragment in the joint restricts spinal movement in some but not all directions, producing the non-capsular pattern characteristic of internal derangement. Third, a displacement protruding posteriorly interferes with the dura mater ; apart from pain, this adversely affects the dura's normal painless mobility. Fourth, a displacement protruding laterally connects with the appropriate nerve root emerging from the dura mater. Finally, compression of the spinal cord strongly contraindicates manipulation, the primary treatment for cartilaginous displacements.

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A Magnetostrictive Force and Vibration Mode Analysis of 3 kW BLDC Motor by a Magneto-Mechanical Coupling Formulation

  • Shin, Pan-Seok;Cheung, Hee-Jun
    • Journal of Electrical Engineering and Technology
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    • 제6권1호
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    • pp.76-80
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    • 2011
  • This paper proposes a method to calculate magnetostrictive forces, displacement, and vibration modes of a large-scale Brushless DC(BLDC) motor by using a magneto-mechanically strong coupling formulation. The force is calculated using the energy method with magnetostrictive stress tensor. The mechanical vibration modes are also analyzed by using the principle of Hamilton and the calculated magneto-elastic forces acting on the surfaces of the stator. To verify the algorithm, 3 MW BLDC motor is simulated, and the forces, displacements, and vibration modes are calculated. The result shows that the mechanically stressed core has more deformation or displacements than those of the normal condition.

철근 콘크리트 보의 손상평가에 대한 실험적 연구 (An Experimental Study on Damage Assessment of Reinforced Concrete Beams)

  • 노원균;심창수;홍창국;김기봉
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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    • pp.60-63
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    • 2004
  • The paper deals with the damage assessment of the concrete beam using static displacements and the flexural stiffness reduction of the beam was evaluated. Simply supported concrete beams were loaded at the mid-span, and the applied load level ranged $20\%,\;40\%,\;80\%$ of the flexural strength of the beam. When the displacements from the tests were increased more than $10\%$ of the initial values, flexural cracks occured. Judging from the observed cracks, damaged area of the beams were assumed and the stiffness reduction using the smeared-cracking concept was estimated to minimize the error between the test results and analytical results. Four stages of the behavior of a RC beam, which are uncracked, initial cracking, stabilized cracking and post-yielding, can be considered to assess the damage of RC beams. Main parameters for the assessment were cracking area and the stiffness reduction ratio. In each stage, damaged elements and their stiffness reduction were estimated to minimized the error.

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