• Title/Summary/Keyword: Displacement

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A development off displacement pump performance evaluation method by using dimensionless parameter (무차원계수를 이용한 왕복펌프의 성능평가 방법 개발)

  • 조희근;윤진하;전종길;김경원;이인복
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.731-734
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    • 2002
  • There have been no obvious design criteria of high efficient displacement pump using a dimensionless parameter which can represent many physical aspect of displacement pump could be very useful to estimate displacement pump performance. Many dimensionless analysis methods have been developed in fluid dynamics, machine design and so on. In this study a new dimensionless parameter is developed for estimate displacement pump performance and efficiency, until now to evaluate the performance of displacement pumps which are widely used in industry field, primarily experimental methods have been used. The dimensionless parameter contains many physical information about pump design. For example, they are the relation between flow rate and power, displacement operation displacement and size, inlet and outlet valve size. And the developed dimensionless functions are induced from numerical method.

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Displacement Measurement of Multi-point Using a Pattern Recognition from Video Signal (영상 신호에서 패턴인식을 이용한 다중 포인트 변위측정)

  • Jeon, Hyeong-Seop;Choi, Young-Chul;Park, Jong-Won
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.18 no.12
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    • pp.1256-1261
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    • 2008
  • This paper proposes a way to measure the displacement of a multi-point by using a pattern recognition from video signal. Generally in measuring displacement, gab sensor, which is a displacement sensor, is used. However, it is difficult to measure displacement by using a common sensor in places where it is unsuitable to attach a sensor, such as high-temperature areas or radioactive places. In this kind of places, non-contact methods should be used to measure displacement and in this study, images of CCD camera were used. When multi-point is measure by using a pattern recognition, it is possible to measure displacement with a non-contact method. It is simple to install and multi-point displacement measuring device so that it is advantageous to solve problems of spatial constraints.

Comparative study on displacement measurement sensors for high-speed railroad bridge

  • Cho, Soojin;Lee, Junhwa;Sim, Sung-Han
    • Smart Structures and Systems
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    • v.21 no.5
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    • pp.637-652
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    • 2018
  • This paper presents a comparative study of displacement measurement using four sensors that are being used in the field: they are a ring gauge, a laser Doppler vibrometer (LDV), a vision-based displacement measurement system (VDMS), and an optoelectronic displacement meter (ODM). The comparative study was carried out on a brand-new high-speed railroad bridge designed to produce displacements within a couple of millimeters under the loading of a high-speed train. The tests were carried out on a single-span steel plate girder bridge two times with different train loadings: KTX and HEMU. The measured displacement is compared as raw and further discussion was made on the measurement noise, peak displacement, and frequency response of four sensors. The comparisonsare summarized to show the pros and cons of the used sensors in measuring displacement at a typical high-speed railroad bridge.

Application of Differential GPS for the Displacement Measurement of Self-anchored Suspension Bridge under the Static and Dynamic Loading Cases (DGPS 기법을 이용한 자정식 현수교의 정동적 변위응답 측정 및 분석)

  • Kim, Hyung-Tae;Seo, Ju-Won
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.19 no.11
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    • pp.1126-1132
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    • 2009
  • Bridge structures are designed to support ordinary loadings such as vehicles, wind, temperature and current as well as unexpected loadings like earthquakes and storm. Especially, the displacement of Flexible bridges like an suspension bridge under ordinary loading conditions is necessary to be monitored. In case of long span bridges, there are some difficulties in monitoring the displacement of center of the main span using traditional laser displacement sensors. In this study, the static and dynamic displacement responses due to vehicle loadings were measured by DGPS(differential global positioning system) technique. The displacement response data were compared with data obtained from traditional laser displacement sensors so that the static and dynamic behavior of the bridge under vehicle loadings was examined and the applicability of the displacement response measurement using DGPS technique was verified. The static and dynamic loading test for an self-anchored suspension bridge, So-rok Bridge, was performed using vehicles. The displacement response from DGPS technique and that from laser displacement sensors of the bridge monitoring system were compared. The amplitude of white noise from DGPS based measurement was about 7 mm and that of laser displacement sensor based measurement was about 3 mm. On the other hand, dynamic behavior of the center of main span from DGPS based measurement showed better agreement with influence line of the bridge than that from laser displacement sensors. In addition, there were some irregular and discontinuous variation of data due to the instability of GPS receivers or frequent appearance of GPS satellites. Post-processing via the reference station close to an observation post provided by NGII(National Geographic Information Institute) will be a counter-plan for these defects.

The expanded LE Morgenstern-Price method for slope stability analysis based on a force-displacement coupled mode

  • Deng, Dong-ping;Lu, Kuan;Wen, Sha-sha;Li, Liang
    • Geomechanics and Engineering
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    • v.23 no.4
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    • pp.313-325
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    • 2020
  • Slope displacement and factor of safety (FOS) of a slope are two aspects that reflect the stability of a slope. However, the traditional limit equilibrium (LE) methods only give the result of the slope FOS and cannot be used to solve for the slope displacement. Therefore, developing a LE method to obtain the results of the slope FOS and slope displacement has significance for engineering applications. Based on a force-displacement coupled mode, this work expands the LE Morgenstern-Price (M-P) method. Except for the mechanical equilibrium conditions of a sliding body adopted in the traditional M-P method, the present method introduces a nonlinear model of the shear stress and shear displacement. Moreover, the energy equation satisfied by a sliding body under a small slope displacement is also applied. Therefore, the double solutions of the slope FOS and horizontal slope displacement are established. Furthermore, the flow chart for the expanded LE M-P method is given. By comparisons and analyses of slope examples, the present method has close results with previous research and numerical simulation methods, thus verifying the feasibility of the present method. Thereafter, from the parametric analysis, the following conclusions are obtained: (1) the shear displacement parameters of the soil affect the horizontal slope displacement but have little effect on the slope FOS; and (2) the curves of the horizontal slope displacement vs. the minimum slope FOS could be fitted by a hyperbolic model, which would be beneficial to obtain the horizontal slope displacement for the slope in the critical state.

Evaluation of Ductility in Reinforced Concrete Members Using Material Models in Eurocode2 (유로코드 2 재료모형을 사용한 철근콘크리트 부재의 연성도 평가)

  • Choi, Seung Won
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.35 no.2
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    • pp.287-297
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    • 2015
  • In concrete structural design provisons, there is a minimum allowable strain of steel to ensure a ductility of RC members and a c/d is limited for the same purpose in EC2. In general, a ductility capacity of RC members is evaluated by a displacement ductility which is a ratio of ultimate displacement to yield displacement, and it is necessary to calculate accurately a yield displacement and an ultimate displacement to evaluate a displacement ductility. But a displacement in members is affected by various member characteristics, so it is hard to calculate a displacement exactly. In this study, a displacement ductility is calculated by calculating a yield displacement and an ultimate displacement through a moment-curvature relationship. The main variables examined are concrete strength, yield strength, steel ratio, spacing of confinement, axial force ratio and concrete ultimate strain. As results, as a concrete strength is increased, a ductility displacement is increased. But as yield strength, steel ratio, spacing of confinement and axial force ratio are increased, a displacement ductility is decreased. And a displacement ductility is necessary to calculate a response modification factor (R) of columns for seismic design, so it is appeared that it is important to calculate a displacement ductility more accurately.

A Experimental Study on the Stability Management Method using change of Inclination for Embankment on Soft Clay (연약지반 성토시의 기울기변화를 이용한 안정관리기법에 관한 실험적 연구)

  • Ryu, Ji-Hoon;Im, Jong-Chul;Chang, Ji-Keon
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.898-905
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    • 2005
  • The settlement of embankment on soft clay includes shear settlement due to shear deformation. Even though the consolidation settlement is not related to lateral displacement, but shear settlement makes the embankment unstable because it deforms ground and decreases the ground strength. In order to determine the shear deformation behaviour during embankment construction, 3 cases (1B, 2B, and 3B) of rapid undrained loading tests on soft clays were performed. Shear settlement is consist of elastic settlement, plastic settlement and viscous settlement. Elastic settlement isn't considered because the range is small, therefore the first is the range of plastic displacement, and the second is that of viscous displacement in the displacement-time curve for each loading stage. After determining that the change in the inclination of the viscous displacement range is larger than in the plastic displacement range after the ground failure occurs for the loading stage, the stability management methods were suggested considering that it is hard to divide the plastic displacement range and the viscous displacement range. The stability management method was based on the ratio of the plastic displacement range's inclination and the viscous displacement range's inclination. A stability management method based on the ratio of the total inclination for each loading stage compared to the whole inclination in the initial loading stage was also recommended.

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Displacement Measurement by Multiplexed Optical Loss -based Fiber Optic Sensor (다중화된 광 손실형 광섬유 센서에 의한 변위의 측정)

  • 권일범;김치엽;유정애
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.556-565
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    • 2003
  • Light losses in optical fibers are investigated by a fiber optic OTDR (Optical Time Domain Reflectometry) sensor system to develop fiber optic probes for structural displacement measurement. The displacement sensitivity was determined by the measurements of fiber-bending loss according to the gage length changes of the displacement sensor. The fiber optic displacement probe was manufactured to verify the feasibility of the structural displacement measurement.

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Improvement for Response Delays of Displacement Magnifier in Jetting Dispenser (젯팅 디스펜서 변위확대장치의 응답지연 개선 연구)

  • Ha, Myeong-Woo;Lee, Kwang-Hee;Hong, Seung-Min;Lee, Chul-Hee
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.26 no.5
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    • pp.546-551
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    • 2016
  • The objective of this study is to investigate the response delays between piezo-stack actuator and the displacement magnifier of jetting dispenser and to reduce its falling time in terms of displacement optimization. The dispenser is driven by the dual piezo-stack actuators with a hinge lever mechanism to precisely control flow rate of the working fluid (3000 cP). It is commonly found that piezo actuator-driven jetting dispensers involving viscous working fluids have displacement optimization problem for ideal performance. The response delay of the system is caused by the phenomenon that the displacement magnifier cannot exactly follow the motion of the piezo actuators. The response delay may lower the performance of the system due to the inaccurate discharge of working fluid or even damages to the system itself due to inharmonious motion of piezo actuators with lever system. To reduce its response delay, a new displacement profile obtained from displacement optimization is suggested; its performance is tested through finite element analysis; and experiments are carried out to verify the performance of the obtained displacement profile.

Study on Assessment of Displacement by Wave Force for Rubble Mound Breakwater and its Application to Design (파랑하중을 받는 굴착치환 사석경사식 방파제의 침하량 산정과 설계 적용성에 관한 연구)

  • Ahn, Ik-Seong;Park, Sang-Kil
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.20 no.4
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    • pp.413-420
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    • 2008
  • Wave force is an important factor which gives a direct affect to stability of the rubble mound breakwater. Particularly wave force has been considered as the main cause of displacement for replaced rubble mound breakwater which permits a little displacement to some degree. But the effect on displacement by wave force has not been considered and reflected in design. Therefore in this study, we compared numerical analysis displacement with field measured displacement so that the effect of wave force on displacement can be reflected in design. Result of the numerical analysis displacement was well consistent with field measured displacement data.