• 한국운동역학회지
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• 제22권4호
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• pp.395-404
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• 2012

This study was to perform the kinetic analysis of tucked backward salto on the balance beam. Eight women's gymnastics players(age: $15.88{\pm}2.45yrs$, career: $6.38{\pm}0.52yrs$, height: $152.38{\pm}7.35cm$, weight: $44.25{\pm}7.54kg$) of the I-region participated in this study. The kinematic variables were analyzed response time of motion, angle, velocity, acceleration and the kinetic variables were analyzed ground reaction force(GRF) of motion. For measure and analysis of kinematic and kinetic variables of this study, used to synchronized to 6 Eagle camera and 1 force plate, used to the Cortex(Ver. 1.0) for analyzed of variables. The results were as follows; To the kinematic variables of tucked backward salto on the balance beam, a time appeared longer landing than air rotation, changes of angle regulated segment of body smaller moment of inertia when air rotation, larger moment of inertia when releasing and landing. A velocity appeared fast motion when releasing and air rotation of body, but appeared more decelerations from landing and acceleration showed to be tended to velocity. A GRF appears jump more than twice the weight at the moment that showed the power of motion to all subject.

• 한국공간구조학회논문집
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• 제4권4호
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• pp.85-89
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• 2004

A frame element embedded normal to a shear wall or slab (shell element) is common in the structural systems. In that case there is a need for a membrane or shell element to have a normal rotation degree of freedom at each node in order to have a good result of stresses. Even if Many other people studied this area, All man, Cook and Sabir are representative investigators in this area. In this research paper, Sabir's methods of vertex rotation stiffness matrix in a membrane element are studied. New stiffness of vertex rotation are proposed by taking advantage of beam stiffness theory. Rectangular elements stiffness with rotational degree of freedom are compared in accuracy ratio each other.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.450-453
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• 1995

The beam rotating actuator, which can be utilized to improve the data transfer rate for the optical disk systems, has been developed. It can employ a newly developed laser beam rotating actuator for putting multi-beam spots on more than one track on the optical disk simultaneously. Therefore, It has to maintain up to .+-.0.01 .deg. resolution and high bandwidth performance. In this these, the Dove prism is used for the beam rotating actuator based on bimorph piezo material. The performance of the beam rotating actuator is verified since the dynamics ferquency performance is measured using the dynamic analyzer and the attached stain gage sensor. the beam rotating angle performance is also examined since the long range beam reflection character is utilized.

• Structural Engineering and Mechanics
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• 제43권2호
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• pp.147-161
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• 2012

This paper presents a curvature method for analysis of beam-columns with different materials and arbitrary cross-section shapes and subjected to combined biaxial moments and axial load. Both material and geometric nonlinearities (the p-delta effect in this case) were incorporated. The proposed method considers biaxial curvatures and uniform normal strains of discrete cross-sections of beam-columns as basic unknowns, and seeks for a solution of the column deflection curve that satisfies force equilibrium conditions. A piecewise representation of the beam-column deflection curve is constructed based on the curvatures and angles of rotation of the segmented cross-sections. The resulting bending moments were evaluated based on the deformed column shape and the axial load. The moment curvature relationship and the beam-column deflection calculation are presented in matrix form and the Newton-Raphson method is employed to ensure fast and stable convergence. Comparison with results of analytic solutions and eccentric compression tests of wood beam-columns implies that this method is reliable and effective for beam-columns subjected to eccentric compression load, lateral bracings and complex boundary conditions.

• Structural Engineering and Mechanics
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• 제55권1호
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• pp.205-228
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• 2015

The results of a numerical investigation pertaining to the hysteretic behaviour of concrete filled steel tubular (CFT) column to I-beam connections are discussed in detail. Following the verification of the numerical results against the available experimental tests, the nonlinear finite element (FE) analysis was implemented to evaluate the effects of different parameters including the column axial load, beam lateral support, shape and arrangement of stiffeners, stiffness of T-stiffeners, and the number of shear stiffeners. Pursuing this objective, an external CFT column to beam connection, tested previously, was selected as the case-study. The lateral forces on the structure were simulated, albeit approximately, using an incremental cyclic loading reversal applied at the beam tip. The results were compared in terms of hysteretic load-displacement curves, stress distributions in connection, strength, rotation, and energy dissipation capacity. It was shown that external T-stiffeners combined with internal shear stiffeners play an important role in the hysteretic performance of CFT columns to I-beam connections.

• 한국공간구조학회:학술대회논문집
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• 한국공간구조학회 2006년도 춘계 학술발표회 논문집 제3권1호(통권3호)
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• pp.256-264
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• 2006

This paper describes the formulation of rectangular flat shell element that is modeled with the six degree of freedoms including a rotational degree of freedom. The rectangular finite element matrix with a rotational degree of freedom is developed using a beam stiffness matrix and compared with other methods. The outputs of the quantity of vertical deflection of cantilever beam show us the improving evidence of the Frame-Shell finite element matrix in a calculation of vertical deflections of cantilever beam.

• 한국강구조학회 논문집
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• 제18권1호
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• pp.59-69
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• 2006

본 연구에서는 보 플랜지 절취형 (Reduced Beam Section, RBS) 철골모멘트접합부의 실험결과를 기초로 패널존의 적정강도를 제시하고자 하였다. RBS 충분한 실험자료가 보고 되어 있음에도 불구하고, 패널존의 적정강도 범위가 아직 제시된 바가 없다. 본 연구 및 다른 연구자의 실험결과에 의할 때, 패널존은 보 플랜지 그루브 용접부에 유해한 영향을 미치지 않고 0.01 radian의 소성회전각을 무난하게 발휘할 수 있음이 확인되었다. 또한 이 정도 크기의 패널존 소성변형을 허용하면 강한 패널존 시험체에 비해 횡비틀림 좌굴의 진폭이 절반 정도로 감소하였다. 이러한 실험적 관측을 토대로 RBS접합부의 소성변형능력을 향상시킴과 동시에 보의 소성힌지에 발생하는 좌굴의 크기를 줄일 수 있는 균형 패널존에 대한 강도 기준을 제안하였다.

• 한국광학회지
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• 제3권2호
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• pp.105-110
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• 1992

광자기 기록 박막의 자기 광학효과에 의한 미소 편광 회전각을 축정하기 위하여 편광 변조 방법을 이용하였다. 편광 변조 방법은 Faraday 회전자로 레이저광의 편광을 변조하고 phase sensitive detection방법을 써서 변조된 신호만을 선택적으로 검출하는 것이다. 본 실험에서는 진공증착법으로 제작된 TbFeCo박막과 RF 스퍼터링으로 제작된 iron garnet 다결정 박막의 자기 Kerr 회전 및 Faraday 회전 이력곡선을 이 방법으로 조사하였다. 그 결과 $0.25^{\circ}$정도의 미소한 회전각을 측정하였으며 특히 longitudinal Kerr 회전의 경우 $2.5\times10^{-3^\circ}$정도의 매우 작은 회전각도 측정할 수 있었다.

• Structural Engineering and Mechanics
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• 제52권2호
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• pp.323-349
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• 2014

In this paper, linear buckling analysis of a curved sandwich beam with a flexible core is investigated. Derivation of equations for face sheets is accomplished via the classical theory of curved beam, whereas for the flexible core, the elasticity equations in polar coordinates are implemented. Employing the von-Karman type geometrical non-linearity in strain-displacement relations, nonlinear governing equations are resulted. Linear pre-buckling analysis is performed neglecting the rotation effects in pre-buckling state. Stability equations are concluded based on the adjacent equilibrium criterion. Considering the movable simply supported type of boundary conditions, suitable trigonometric solutions are adopted which satisfy the assumed edge conditions. The critical uniform load of the beam is obtained as a closed-form expression. Numerical results cover the effects of various parameters on the critical buckling load of the curved beam. It is shown that, face thickness, core thickness, core module, fiber angle of faces, stacking sequence of faces and openin angle of the beam all affect greatly on the buckling pressure of the beam and its buckled shape.

• 국제강구조저널
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• 제18권5호
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• pp.1772-1783
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• 2018

Nowadays, the researches about composite structure system are being implemented in various fields, and many steel structures are designed based on that. In this study, the bending and seismic performance of the newly developed high-performance cold forming composite beam are evaluated by several experiments. As a result of the bending performance test, the bending moment of beam was increased stably depending on the depth and plate thickness of beam, and it is considered that the bending moment can be evaluated by the equation of a composite beam design. As a result of the seismic performance test, it was verified that sufficient seismic performance was obtained despite the increase of a negative moment rebar and depth of beam. In addition, the nominal bending moment has obtained the strength above the plastic bending moment, and also the plastic rotation angle has satisfied the requirement of composite intermediate moment frame.