• 대한기계학회:학술대회논문집
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• 대한기계학회 2005년도 창립60주년 기념 추계 학술대회
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• pp.183.2-183.2
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• 2005

• Ocean Systems Engineering
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• 제4권2호
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• pp.99-115
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• 2014

When caissons are mounted on a floating transportation barge and towed by a tug boat in waves, motion of the floating dock creates inertia and gravity-induced slip forces on the caisson. If its magnitude exceeds the corresponding friction force between the two surfaces, a slip may occur, which can lead to an unwanted accident. In oblique waves, both pitch and roll motions occur simultaneously and their coupling effects for slip and friction forces become more complicated. With the presence of strong winds, the slip force can appreciably be increased to make the situation worse. In this regard, the safety of the transportation process of a caisson mounted on a floating dock for various wind-wave conditions is investigated. The analysis is done by both frequency-domain approach and time-domain approach, and their differences as well as pros and cons are discussed. It is seen that the time-domain approach is more direct and accurate and can include nonlinear contributions as well as viscous effects, which are typically neglected in the linear frequency-domain approach.

• Structural Engineering and Mechanics
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• 제73권2호
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• pp.143-152
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• 2020

Deep coupling beams are more prone to suffer brittle shear failure. The addition of steel fibers to seismic members such as coupling beams can improve their shear performance and ductility. Based on the test results of steel fiber reinforced concrete(SFRC) coupling beams with span-to-depth ratio between 1.5 and 2.5 under lateral reverse cyclic load, the shear mechanism were analyzed by using strut-and-tie model theory, and the effects of the span-to-depth ratio, compressive strength and volume fraction of steel fiber on shear strengths were also discussed. A simplified calculation method to predict the shear capacity of SFRC deep coupling beams was proposed. The results show that the shear force is mainly transmitted by a strut-and-tie mechanism composed of three types of inclined concrete struts, vertical reinforcement ties and nodes. The influence of span-to-depth ratio on shear capacity is mainly due to the change of inclination angle of main inclined struts. The increasing of concrete compressive strength or volume fraction of steel fiber can improve the shear capacity of SFRC deep coupling beams mainly by enhancing the bearing capacity of compressive struts or tensile strength of the vertical tie. The proposed calculation method is verified using experimental data, and comparative results show that the prediction values agree well with the test ones.

• 콘크리트학회논문집
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• 제18권1호
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• pp.135-145
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• 2006

In high multistory reinforced concrete buildings, coupled shear walls can provide an efficient structural system to resist horizontal force due to wind and seismic effects. Coupled shear walls are usually built over the whole height of the building and re laid out either as a series of walls coupled by beams and/or slabs or a central core structure with openings to accommodate doors, elevators walls, windows and corridors. A number of recent studies have focused on examining the seismic response of concrete, steel, and composite coupling beams. However, since no specific equations are available for computing the bearing strength of steel coupling beam-wall connections, it is necessary to develop such strength equations. There were carried out analytical and experimental studies to develop the strength equations of steel coupling beam-connections. Experiments were conducted to determine the factors influencing the bearing strength of the steel coupling beam-wall connection. The results of the proposed equations were in good agreement with both test results and other test data from the literature. Finally, this paper provides background for design guidelines that include a design model to calculate the bearing strength of steel coupling beam-wall connections.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.1038-1042
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• 2003

In order to evaluate dynamic impedance of a hand-arm system it is necessary to measure the hand-transmitted vibration and the reaction force at the same time while gripping the vibrating handle. In the study a device was developed to measure both the vibration and the force. The device consists of a measurement handle with four strain gauge and two accelerometers and a PC based control system with a program for the signal processing and evaluation of the hand-transmitted vibration and reaction force. The handle was installed on the vibration shaker so that it can move by the generated signal from the control system. As an application of the system dynamic reaction force and the frequency weighted acceleration at the handle attached to the shaker were measured at various grip force and feed force. This system will be very useful in the area of impedance measurement and the evaluation of performance of anti-vibration gloves.

• Smart Structures and Systems
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• 제33권1호
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• pp.1-16
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• 2024

The investigation on vehicle-bridge coupling system (VBCS) is crucial in bridge design, bridge condition evaluation, and vehicle overload control. A real-time hybrid testing (RTHT) method for VBCS (RTHT-VBCS) is proposed in this paper for accurately and economically disclosing the dynamic performance of VBCSs. In the proposed method, one of the carriages is chosen as the experimental substructure loaded by servo-hydraulic actuator loading system in the laboratory, and the remaining carriages as well as the bridge structure are chosen as the numerical substructure numerically simulated in one computer. The numerical substructure and the experimental substructure are synchronized at their coupling points in terms of force equilibrium and deformation compatibility. Compared to the traditional iteration experimental method and the numerical simulation method, the proposed RTHT-VBCS method could not only obtain the dynamic response of VBCS, but also economically analyze various working conditions. Firstly, the theory of RTHT-VBCS is proposed. Secondly, numerical models of VBCS for RTHT method are presented. Finally, the feasibility and accuracy of the RTHT-VBCS are preliminarily validated by real-time hybrid simulations (RTHSs). It is shown that, the proposed RTHT-VBCS is feasible and shows great advantages over the traditional methods, and the proposed models can effectively represent the VBCS for RTHT method in terms of the force equilibrium and deformation compatibility at the coupling point. It is shown that the results of the single-degree-of-freedom model and the train vehicle model are match well with the referenced results. The RTHS results preliminarily prove the effectiveness and accuracy of the proposed RTHT-VBCS.

• Bulletin of the Korean Chemical Society
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• 제33권3호
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• pp.897-900
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• 2012

We examined theory for force-induced unbinding on a two-dimensional free energy surface where the internal dynamics of biomolecules is coupled with the rupture process under constant tension f. We show that only if the transition state ensemble is narrow and activation barrier is high, the f-dependent rupture rate in the 2D potential surface can faithfully be described using an effective 1D energy profile.

• 한국신뢰성학회지:신뢰성응용연구
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• 제14권4호
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• pp.236-242
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• 2014

Since permanent magnet coupling transfers power by magnetic force without contact, it has little shock, vibration, noise. In case of overload, it protects a pump or a motor which is relatively important by slipping internally. In this study, failure analysis and test evaluation on the permanent magnet coupling have been proposed and the process that reliability of the product improves through design improvement has been presented. And failure cause of typical failure case has been investigated and improvement plan has been presented. Finally, reliability improvement is established by analysis of the test results of before and after acceleration test.

• 소음진동
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• 제8권2호
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• pp.306-312
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• 1998

This paper proposes a method for estimating the vibrational power supplied by a machine that generates excitation force to its supporting structure via the coupling points. The basis of the method is that the vibrational power can be calculated using the mechanical impedance and the velocity at the coupling points on the supporting structure. First, a method is described to estimate the mobilities at the coupling points when the machine is not separable from the supporting structure, then the vibrational power is calculated using the estimated mobilities and measured velocities at the coupling points. The mobilities are estimated from the result of impulsive testing of the coupled structure. The method is investigated using an experimental model. The estimated and measured values of the mobilities and the vibrational power are compared. It is shown that the estimated values agree well with the measured values.

• 정보저장시스템학회논문집
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• 제3권2호
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• pp.59-65
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• 2007

Scanning Prove Microscope (SPM) - based Data Storage (SDS)는 Atomic Force Microscope (AFM)을 이용하여 Cantilever Tip 이 저장 장치 미디어에 나노미터 단위로 비트를 읽고, 쓰고 지우는 저장 장치로써, x, y 두 축을 이용한다. 따라서 축간 coupling 의 영향이 크게 발생한다. 따라서 축간 coupling 의 영향을 고려하여 제어기를 설계하여야 한다. 본 논문은 coupling 요소를 제거하기 위하여 Feedforward Decoupler 를 설계하여 Stage 의 입력 앞 단에 추가하는 방법을 제안하였다. Feedforward Decoupler 를 추가함으로써 coupling 요소가 줄어드는 것을 모의 실험을 통해 확인한다. 이를 통해 나노급으로 보다 정밀한 제어가 가능함을 확인하였다.