• Title/Summary/Keyword: Hysteresis curve

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Development of a Compensating Algorithm for an Iron-cored Measurement CT using Flux-magnetizing Current Curves and Voltage-core Loss Current Curves (자속-자화 전류 곡선과 전압-철손 전류 곡선을 이용한 측정용 철심 변류기의 보상 알고리즘 개발)

  • Kang, Yong-Cheol;Zheng, Tai-Ying;Kang, Hae-Gweon;Lee, Byung-Eun;Kim, Yong-Gyun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.10
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    • pp.1849-1854
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    • 2009
  • This paper describes the design, evaluation and implementation of a compensating algorithm for an iron-cored measurement current transformer (CT) that removes the effects of the hysteresis characteristics of the iron-core. The exciting current resulting from the hysteresis characteristics of the core causes an error of the CT. The proposed algorithm decomposes the exciting current into the core loss current and the magnetizing current and each of them is estimated. The core loss current is calculated from the secondary voltage and the voltage-core loss current curve. The core flux linkage is calculated and then inserted into the flux-magnetizing current curve to estimate the magnetizing current. The exciting current at every sampling interval is obtained by summing the core loss and magnetizing currents and then added to the measured current to obtain the correct secondary current. The voltage-core loss current curve and flux-magnetizing current curves, which are different from the conventional curves, are derived in this paper. The performance of the proposed algorithm is validated under various conditions using EMTP generated data. The experimental test results of an iron-core type electronic CT, which consists of the iron-core and the compensation board, are also included. The results indicate that the proposed algorithm can improve the accuracy of the measurement CT significantly, and thus reduce the size and the cost of the CT.

Effect of Hysteresis on Soil-Water Characteristic Curve in Weathered Granite and Gneiss Soil Slopes during Rainfall Infiltration (풍화계열 사면의 불포화 함수특성곡선 이력이 강우 침투에 미치는 영향)

  • Shin, Gil-Ho;Park, Seong-Wan
    • Journal of the Korean Geotechnical Society
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    • v.22 no.7
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    • pp.55-64
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    • 2006
  • Shallow failures of slopes in weathered soils are caused by infiltration caused by prolonged rainfall. These failures are mainly triggered by the deepening of the wetting band accompanied by a decrease in suction induced by the water infiltration. In this paper, hysteresis on soil-water characteristic curve (SWCC) of granite and gneiss weathered soils is investigated using transient flow analysis respectively. Each case was subjected to artificial rainfall intensities and time duration depending on the laboratory-based drying and wetting processes. The results show that the unsaturated seepage on weathered slopes are very much affected by the initial suction of soils and unsaturated permeability of the soils. In addition, a granite weathered soil has a lower air-entry value, residual matric suction, and wetting front suction and less hysteresis loop than a gneiss weathered soil.

A Study on Measuring Soil-Water Characteristic Curve Using a Suction Control Technique (흡입력 조절 기법을 이용한 함수특성곡선 측정에 관한 연구)

  • Lee, Joonyong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.11
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    • pp.5587-5594
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    • 2012
  • Determination of the soil-water characteristic curve is one of the most important things to solve geotechnical engineering problems. Expecially, convenient and reliable method to measure the soil-water characteristic curve during drying and wetting cycles is required with lower labor input, more independence from operator experience, and shorter testing time than other available methods. Many measurement methods including the flow pump system have been developed to characterize the soil-water characteristic curve for the several decades. This study measured the soil-water characteristic curve during drying and wetting cycles using a suction control technique with the flow pump system. Two test materials were used for determination of the soil-water characteristic curve, and it is concluded that suction control technique is suitable for determination of the soil-water characteristic curve and characterization of the hydraulic hysteresis with varying test conditions. Especially, the suction control technique can reduce error of measurement and save time in measuring the soil-water characteristic curve due to automated system and high degree of precision.

Determination of Soil Water Characteristic Curve and Permeability Equation of Unsaturated Soils Using Modified Triaxial Apparatus (변형된 삼축시험장치를 이용한 불포화토의 함수특성곡선과 투수계수방정식의 결정)

  • Kim Suk-Nam;Park Chi-Won;Mok Young-Jin;Kim Suk-Myung
    • Journal of the Korean Geotechnical Society
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    • v.21 no.5
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    • pp.59-64
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    • 2005
  • In studying unsaturated soil mechanics, determination of soil water characteristic curve and permeability equation though not easy, is an essential factor. In this research a new testing apparatus was developed to determine soil water characteristic curve and permeability equation. A test to get saturated permeability coefficients and soil water characteristic curves for two soils was performed by using the developed testing apparatus. First, a saturated permeability test was performed and then the test to get soil water characteristic curve of a drying process was performed. Next, the test to get soil water characteristic curve of a wetting process was performed. Test results showed hysteresis phenomena between soil water characteristic curve of a drying process and soil water characteristic curve of a wetting process. The permeability equations were determined by a theoretical method where a saturated permeability coefficient and a soil water characteristic curve were used.

Compensating algorithm for the secondary current of a measurement type CT considering the secondary voltage-core loss current curve and the flux linkage-magnetizing current curve (2차 전압-철손 전류 곡선과 자속-자화 전류 곡선을 고려한 측정용 변류기 2차 전류 보상 알고리즘)

  • Kang, Yong-Cheol;Zheng, Tai-Ying;Jang, Sung-Il;Kim, Yong-Gyun
    • Proceedings of the KIEE Conference
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    • 2008.07a
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    • pp.65-66
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    • 2008
  • This paper proposes a compensating algorithm for the secondary current of the measurement current transformer (CT) that removes the effects of the hysteresis characteristics of the iron-core. The exciting current resulting from the hysteresis characteristics of the core causes an error between the primary current and the secondary current of the CT. The proposed algorithm decomposes the exciting current into the magnetizing current and the core loss current and each of them is estimated. The core loss current is calculated from the secondary voltage and the secondary voltage-core loss current curve. The core flux linkage is calculated and then inserted into the flux-current curve to estimate the magnetizing current. The exciting current at every sampling interval is obtained by summing the core-loss and magnetizing currents and then added to the measured current to compensate the secondary current. The performance of the proposed algorithm is validated under various conditions using EMTP generated data. The test results of the real CT were also included. The results indicate that the proposed algorithm can improve the accuracy of the measurement CT significantly, and thus reduce the size and the cost of the CT.

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Behaviour of lightweight aggregate concrete-filled steel tube under horizontal cyclic load

  • Fu, Zhongqiu;Ji, Bohai;Wu, Dongyang;Yu, Zhenpeng
    • Steel and Composite Structures
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    • v.32 no.6
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    • pp.717-729
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    • 2019
  • A horizontal cyclic test was carried out to study the seismic performance of lightweight aggregate concrete filled steel tube (LACFST). The constitutive and hysteretic model of core lightweight aggregate concrete (LAC) was proposed for finite element simulation. The stress and strain changes of the steel tube and concrete filled inside were measured in the experiment, and the failure mode, hysteresis curve, skeleton curve, and strain curve of the test specimens were obtained. The influence of axial compression ratio, diameter-thickness ratio and material strength were analysed based on finite element model. The results show that the hysteresis curve of LACFST indicated favourable ductility, energy dissipation, and seismic performance. The LACFST failed when the concrete in the bottom first crushed and the steel tube then bulged, thus axial force imposed by prestressing was proved to be feasible. The proposed constitutive model and hysteretic model of LAC under the constraint of its steel tube was reliable. The bearing capacity and ductility of the specimen increase significantly with increasing thickness of the steel tube. The bearing capacity of the member improves while the ductility and energy dissipation performance slightly decreased with the increasing strength of the steel and concrete.

A Study of Dynamic Characteristic of the Leaf Spring for Freight Wagon After the Derailment (탈선 후 화물열차의 겹판스프링 동적특성 연구)

  • 이응신;이장무
    • Journal of the Korean Society for Railway
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    • v.7 no.1
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    • pp.49-54
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    • 2004
  • Particularly derailing freight wagon, which are loaded with dangerous chemicals, has large damages on humans and environment. In this paper the dynamic characteristic of the laminated leaf spring under extreme situation, for example derailment, is examined. The leaf spring has a static hysteresis. Not only the friction value, but also the spring rate are influenced by this hysteresis characteristic. Because of the static hysteresis of the leaf spring the spring rate must be used in normal operation depending upon the loading and the kind of the excitation with the up to 10-fold value of the static spring rate. Some characteristics of the leaf spring can be treated like well-known viscous damping, but fer special situation (preload and/or excitation) particular calculation are necessary.

Hysteresis Modeling and Control of Terfenol-D Actuator (Terfenol-D 액츄에이터의 히스테리시스 모델링과 제어)

  • Park, Y. W.;M. C. Lim;Kim, D. Y.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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    • pp.660-663
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    • 2003
  • This paper proposes a systematic approach for an accurate control of the Terfenol-D actuator taking into account hysteresis, modeled by applying the classical Preisach operator with memory curve. A desired input displacement is calculated by using the hysteresis inverter, which is fed into the actuator. Then the PI compensator corrects the error between the commanded and actual displacements. Experiments with the step responses show that the PI controller settles in 70 ms and the hybrid controller in 20 ms. It means that the concurrent application of two control schemes is effective to control the actuator.

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Research on a novel shear lead damper: Experiment study and design method

  • Chong, Rong; Wenkai, Tian;Peng, Wang;Qingxuan, Shi
    • Steel and Composite Structures
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    • v.45 no.6
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    • pp.865-876
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    • 2022
  • The slit members have lower strength and lower stiffness, which might lead to lower energy dissipation. In order to improve the seismic performance of the slit members, the paper proposes the shear lead damper, which has stable performance and small deformation energy dissipation capacity. Therefore, the shear lead damper can set in the vertical silts of the slit member to transmit the shear force and improve energy dissipation, which is suitable for the slit member. Initially, the symmetrical teeth-shaped lead damper was tested and analyzed. Then the staggered teeth-shaped lead dampers were developed and analyzed, based on the defect analysis and build improvements of the symmetrical specimen. Based on the parameter analysis, the main influence factors of hysteretic performance are the internal teeth, the steel baffles, and the width and length of damper. Finally, the theoretical analysis was presented on the hysteretic curve. And the skeleton curve and hysteresis path were identified. Based on the above theoretical analysis, the design method was proposed, including the damping force, the hysteresis model and the design recommendations.