• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.846-853
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• 2006

In this study, quantitative sensitivity analysis on rockfill material influencing the dam crest displacement of Concrete-Faced Rockfill Dam(CFRD) was carried out. The purpose of this study is to indicate the most important input parameter and to show the quantitative variation of displacement at the crest of CFR type dam with this input parameter. The rockfill material properties for parametric study were obtained from the results of large scale triaxial tests on 34 rockfill materials in the 22 different sites. From the statistical analysis on these data, some statistical characteristics of rockfill material properties such as property range, distribution characteristics, and correlation between the properties were investigated. based on these characteristics, 27 property combinations were constituted by Latin Hypercube sampling method. Dam crest displacements after construction, impounding, and earthquake loading were evaluated by static and dynamic numerical analysis on each combination. From the sensitivity analysis, it was found that the crest displacement of CFR type dam was absolutely affected by the shear modulus of rockfill material and the effect of friction angle of it was negligible. This relative difference of sensitivity was more outstanding in case of crest settlement than in case of crest horizontal displacement. Also, it was found that the settlement and horizontal displacement of dam crest logarithmically decreased as the shear modulus increased and the difference between the maximum value and the minimum vale amounted to about 9.5 times in case of settlement and about 10 times in case of horizontal displacement.

• Journal of Mechanical Science and Technology
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• 제19권2호
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• pp.520-528
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• 2005

In this study, a new mathematical dynamic model of displacement sensitive shock absorber (DSSA) is proposed to predict the dynamic characteristics of automotive shock absorber. The performance of shock absorber is directly related to the vehicle behaviors and performance, both for handling and ride comfort. The proposed model of the DSSA has two modes of damping force (i.e. soft and hard) according to the position of piston. In this paper, the performance of the DSSA is analyzed by considering the transient zone for more exact dynamic characteristics. For the mathematical modeling of DSSA, flow continuity equations at the compression and rebound chamber are formulated. And the flow equations at the compression and rebound stroke are formulated, respectively. Also, the flow analysis at the reservoir chamber is carried out. Accordingly, the damping force of the shock absorber is determined by the forces acting on the both side of piston. The analytic result of damping force characteristics are compared with the experimental results to prove the effectiveness. Especially, the effects of displacement sensitive orifice area and the effects of displacement sensitive orifice length on the damping force are observed, respectively. The results reported herein will provide a better understanding of the shock absorber.

• 대한건축학회논문집:구조계
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• 제34권1호
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• pp.33-39
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• 2018

This study performed experimental validation of the hysteretic steel slit damper's basic and dependent characteristics, which should be considered for the design. The basic characteristic of the steel slit damper is used for determining design properties of non-linear analysis, such as yielding strength, yielding displacement, elastic stiffness and post-yielding stiffness. In order to evaluate dependent characteristics of the hysteretic steel slit damper, repeated deformation capacity with respect to the displacement, velocity and aspect ratio of the damper was evaluated. In this study, steel slit damper, which is widely used in Korea, was considered. The slit dampers with 55kN and 240kN of yielding strength were produced and tested. It was concluded that the slit damper's hysteresis behavior was affected by the dependent characteristics: displacement, velocity and aspect ratio. In other words, the steel slit damper's behavior was stable within limit displacement, and aspect ratio of the strut affected repeated deformation capacity of the damper subjected to large deformation. In addition, it was observed that the repeated deformation capacity abruptly decreased at the high speed range (${\geq}60mm/sec$). Furthermore, the experimental results were evaluated with the criterion of the damping device specified in ASCE7-10.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부 C
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• pp.844-846
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• 1998

In this study, Brass endcap with 2, 3, 5, and 7mm contact surface and 0.6, 0.9, 1.2, 1.5mm conical cavity depths was fabricated by the punch die while keeping the cavity diameter constant 9.25mm then displacement characteristics of the cymbal actuators with each of brass endcap thickness were measured under an applied voltage $60V_{max}$. Dispacement increased with increasing contact surface and resonant frequency decreased with increasing contact surface, cymbal actuator with 7mm contact surface and 1.5mm endcap cavity depth exhibits $35.89{\mu}m$ displacement and 18.8kHz resonant frequency, displacement increased with increasing endcap cavity depth while contact surface was kept constant at 3mm and Below a endcap thickness of 0.2mm, Differences in displacement between 1.2mm and 1.5mm cavity depth appeared at $0.18{\mu}m$. that is, displacement of cymbal actuator with 1.2mm over cavity depth saturated nearly.

• Smart Structures and Systems
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• 제16권3호
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• pp.521-535
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• 2015

Vibration-based monitoring is one approach used to perform structural condition assessment. By measuring structural response, such as displacement, dynamic characteristics of a structure may be estimated. Often, the primary dynamic responses in civil structures are below 5 Hz, making accurate low frequency measurement critical for successful dynamic characterization. In addition, static deflection measurements are useful for structural capacity and load rating assessments. This paper presents a DC coupled continuous wave radar to accurately detect both dynamic and static displacement. This low-cost radar sensor provides displacement measurements within a compact, wireless unit appropriate for a range of structural monitoring applications. The hardware components and operating mechanism of the radar are introduced and a series of laboratory experiments are presented to assess the performance characteristics of the radar. The laboratory and field experiments investigate the effect of factors such as target distance, motion amplitude, and motion frequency on the radar's measurement accuracy. The results demonstrate that the radar is capable of both static and dynamic displacement measurements with sub-millimeter accuracy, making it a promising technology for structural health monitoring.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 추계학술대회 논문집
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• pp.306-308
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• 1997

The Maxwell displacement current was investigated in the connection with stwiching characteristics by photoisomerization of monolayers. The displacement current was generated due to the trans-to-cis photoisomerization by irradiation with ultraviolet light( λ$_1$1=360nm). whereas the displacement current was generated in the opposite direction due to the sis-to-trans photoisomerization by irradiation with visible light( λ$_1$=450nm). The reversible displacement current generation was found to be sustained by alternative irradiation with UV light and visible light.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.947-954
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• 2008

Nowadays many urban subways are frequently constructed under the building and the river by the use of tunneling method. Especially, the majority of the tunnel are constructed even with shallow depth under the ground in the weathered soil. Since the tunnel are generally designed on the basis of the geographic soil investigation, the stability of the tunnel should be checked with the realistic data instrumented during construction. The displacement of the tunnel occurs in front of the end face during the excavation of the tunnel, which is called as pre-displacement. The total displacement can be figured from the exact pre-displacement, which is very difficult to measure without using any device installed in front of the tunnel end face. In this study, the pre-displacement measured from horizontal inclinometer was analyzed to know the co-relation with the total displacement and also, the trend and the characteristics of the tunnel deformation during construction was suggested through the regression analysis of the measured data.

• 한국재난정보학회 논문집
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• 제12권1호
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• pp.40-46
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• 2016

Nowdays, adjacent loading bringing enormous harm to the existing bridge in engineering construction. In this paper, the influencing mechanism of adjacent loading to pier and Law of displacement of pier is researched through living examples, and the safe influence area has been defined. Research shows that: the main damages to piers is caused by the side loading; lateral displacement index of pier top surface is more conservative than the pier additional stress index; it is secure when the distance of adjacent load is 0.5 times of the height of accumulation or 6m, otherwise it would be very scary, and the monitoring measure is necessary.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제5B권1호
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• pp.90-94
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• 2005

As the structure of the piezoelectric bimorph cantilever becomes increasingly more complicated, a more accurate and efficient analysis of piezoelectric media is needed. In this paper, the piezoelectric transducer is analyzed by using the three-dimensional finite element method. The validity of the three-dimensional finite element routine is confirmed by comparing the experimental result. The resonance characteristics, such as resonance frequency and anti-resonance frequency, of the piezoelectric cantilever are calculated by the experimentally verified three dimensional finite element method. Subsequently, the characteristics, such as mechanical displacement and impedance, are calculated at the resonance frequency. Besides, to design the piezoelectric bimorph cantilever shape that maximizes displacement at the tip, the ES (Evolution Strategy) algorithm is applied. Finally, optimal design for the fan of the piezoelectric cantilever is fulfilled to obtain maximum displacement at the tip. From these results, the application potentiality of the piezoelectric bimorph cantilever fan is identified.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.246-251
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• 2003

This paper presents an experimental study on the energy dissipation characteristics of viscous damping wall (VDW). VDW is consisted of a plate floating in a thin case made of steel plated filled with highly viscous silicone oil. Because VDW demonstrates both viscous damping and stiffness characteristics, the viscous resisting force can be expressed as the sum of velocity dependant viscous damping force and displacement dependant restoring force. The viscous resisting force and energy absorbing capacity can be easily adjusted by changing three factors, i.e. viscosity of the fluid, gap distance and area of the wall plates. VDW was tested using a series of harmonic (sinusoidal) displacement history having different frequency and amplitude and the force-displacement relationship was recorded. The relationship between dissipated energy with three factors and the influence of exciting frequency on resisting force were Investigated