• 한국강구조학회 논문집
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• 제13권2호
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• pp.211-221
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• 2001

본 연구에서는, 포장가속시험시설이 사용 중 발생 가능한 동역학적 힘을 예측하기 위해, 이미 개발되어 운용중인 모형시험시설을 이용하여 차량 운동방정식을 구하고, 모형시험시설과 포장가속시험시설(KALES : Korea Accelerated Loading and Environmental Simulator)의 상사관계를 이용하여 KALES가 운행 중 발생할 수 있는 동역학적인 힘을 예측하였다. 이를 기반으로 실제 차량 구조부 형상에 대한 상세설계를 전산해석과 피로수명평가 방법을 이용하여 수행하였다. 해석 결과, 동역학적 모형화 및 피로강도 해석기술을 기반으로 설계된 KALES는 시험 중 발생되는 사용하중 이력에 대해서 피로 강도적으로 충분한 안전성이 확보되도록 설계됨을 확인할 수 있었다.

• 한국해양공학회지
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• 제35권5호
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• pp.347-359
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• 2021

This study aims to evaluate the dynamic responses of the jacket-type offshore wind turbine using FAST software (Fatigue, Aerodynamics, Structures, and Turbulence). A systematic series of simulation cases of a 5 MW jacket-type offshore wind turbine, including wind-only, wave-only, wind & wave load cases are conducted. The dynamic responses of the wind turbine structure are obtained, including the structure displacement, rotor speed, thrust force, nacelle acceleration, bending moment at the tower bottom, and shear force on the jacket leg. The calculated time-domain results are transformed to frequency domain results using FFT and the environmental load with more impact on each dynamic response is identified. It is confirmed that the dynamic displacements of the wind turbine are dominant in the wave frequency under the incident wave alone condition, and the rotor thrust, nacelle acceleration, and bending moment at the bottom of the tower exhibit high responses in the natural frequency band of the wind turbine. In the wind only condition, all responses except the vertical displacement of the wind turbine are dominant at three times the rotor rotation frequency (considering the number of blades) generated by the wind. In a combined external force with wind and waves, it was observed that the horizontal displacement is dominant by the wind load. Additionally, the bending moment on the tower base is highly affected by the wind. The shear force of the jacket leg is basically influenced by the wave loads, but it can be affected by both the wind and wave loads especially under the turbulent wind and irregular wave conditions.

• 산업기술연구
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• 제28권A호
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• pp.155-161
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• 2008

Muscle force prediction in forward dynamic analysis of human motion depends many muscle parameters associated with muscle actuation. This research studies the effects of various parameters of Hill type muscle model using the simple hand raising motion. Motion analysis is carried out using motion capture system, and each muscle force is recorded for comparison with muscle model generated muscle force. Using Hill type muscle model, muscle force for generating the same hand rasing motion was setup adjusting 5 activation parameters. The test showed the importance of activation parameters on the accurate generation of muscle force.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2007년도 정기총회 및 학술발표대회
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• pp.45-48
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• 2007

The aim of this study is to estimate the compressive force of steel member using a system identification technique with vibration measurements. To date, several methods have been presented to estimate the compressive force using static and/or dynamic responses of the steel member. However, each and every one of these methods has its disadvantages as well as advantages in its procedures, level of accuracy, and equipment requirements. The paper reports a qualitative investigation of vibration under monoharmonic excitation. The methodology utilizes the relationship between the natural frequencies, the structural parameters, and the compressive force of the member. In this paper, experimental results are presented with a steel beam subjecting to several compressive forces and the proposed method is validated using both numerical and experimental data.

• 한국정밀공학회지
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• 제22권4호
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• pp.107-112
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• 2005

In this study, the dynamic analysis is performed fur predicting the transmitted force to flexible human body induced by prototype HIF(High Impulsive force) device operation, which is partially assembled by major parts. A beam-mass model and a shear-structure model are used for the flexible mount structure and their dynamic behavior are investigated by experimental results under rigid/flexible mount conditions using a general purpose device. From the test result of prototype device in rigid mount condition, the transmitted force to human body which can not be measured directly, is estimated based on the proved mount structure model.

• Journal of Electrical Engineering and Technology
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• 제10권4호
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• pp.1667-1673
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• 2015

The vibration and noise caused by the dynamic interaction between electromagnetic suspension and the linear synchronous motor stator beneath a flexible guideway remain problems in designing attractive Maglev trains. One possible method to reduce the sources of vibration is to minimize the detent force in the linear synchronous motor that creates variations in both lift force and thrust. This paper proposes lowering detent force by using separated core instead of single united core. The magnet is designed to adapt to the deflected guideway at a speed of 550km/h. This study will analyze the electromagnetic field and control performance, and how they relate to lift forces and dynamic responses.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 춘계학술대회 논문집
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• pp.313-318
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• 1996

This paper deals with the dynamic behavior of elastic columns under the action of subtangential forces. The above subtangential force can be-realized by the combination force between the dead load of thetip mass and the pure follower thrust. The tip mass is assumed to be a rigid body not a mass point as it has been assumed so for. The equations of motion are formulated based on extended Hamilton's principle and the finite element method. It is shown that nonconservativeness of the applied force has greatly effect on the instability type. It is found that the critical subtangential force can also be changed by consideration of the tip mass parameters taking into account of its magnitude, rotary inertia and size. The influence of the self-weight of the column on the change of the critical force is also investigated.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.972-977
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• 2009

For the improvement of a train speed in the conventional line from overhead system point of view, it is necessary to approach not only in the aspect of the increasement of tension for catenary but the application of a pre-sag. A certain tension acting on a dropper is removed when it is slack by the pantograph passing. Right after the pantograph passes, the dynamic force caused by the mass of contact wire acts on the dropper. If the pre-sag is applied to the catenary, the static force on the dropper is increased. For the assurance of the safety for the dropper, it is necessary to predict the dynamic force. The purpose of this study is to predict and analyze the force on the dropper according to the applied pre-sag.

• 한국CDE학회논문집
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• 제15권1호
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• pp.70-83
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• 2010

Recently, floating cranes are mainly used to erect heavy blocks or cargos for constructing ships in many shipyards. It is important to estimate the dynamic motion of the heavy cargo suspended by a floating crane and the tension of the wire ropes between the floating crane and the heavy cargo. In this paper, the coupled dynamic equations of motion are set up for considering the 6 degree-of-freedom floating crane and the 6-degrees-of-freedom heavy cargo based on multibody system dynamics. Depending on the cargo weight, the motion of the floating crane would be changed to nonlinear state. The nonlinear terms in the equation of motion are considered. In addition, the nonlinear hydrostatic force, the linear hydrodynamic force, wire rope force, mooring force and gravity force are considered as the external forces. As the result of this paper, we analyze the engineering effect for erecting the heavy cargo by using the floating crane.

• 유공압시스템학회:학술대회논문집
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• 유공압시스템학회 2010년도 춘계학술대회
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• pp.1-6
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• 2010

Direct Drive Valves (DDV) with electric closed loop spool position control are suitable for electrohydraulic position, velocity, pressure or force control systems including those with high dynamic response requirements. The spool drive device is a permanent magnet linear force motor which can actively stroke the spool from its spring centered position in both directions. This basic study is carried out to drive the design parameters for developing a domestic DDV. The static and dynamic characteristics of DDV are examined. The simulation results are compared with data of manufacture's catalog to show the validity of the modelling.