• Title/Summary/Keyword: Force curve

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Safety evaluation of tilting train on circular curve (틸팅열차의 원곡선부 주행시 안전성 평가)

  • Kim, Sang-Soo;Eum, Ki-Young;Bae, Jae-Hyoung
    • Proceedings of the KSR Conference
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    • 2010.06a
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    • pp.1703-1712
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    • 2010
  • The safety of tilting train running on curved track is, in general, evaluated with a derailment coefficient calculated by the ratio of wheel load and lateral force, Particularly on curve, the wheel load and lateral force on rail may cause trackbed to be deformed, depending on their intensity, and moreover, often result in critical accident such as derailment. This study hence was intended to identify the cause of wheel load and lateral force so as to suggest the allowable wheel load reduction rate, lateral force limit and derailment coefficient, thereby quantitatively evaluating the operational safety of tilting train. This study therefore was aimed to analyze the wheel load and lateral force occurred during tilting train's operation on circular curve in such a way of comparing with traditional trains, by axle and speed, in a bid to eventually evaluate the operational safety of tilting train.

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Study on The Suggested Curve Fitting Algorithm for Bolt Clamping Force Measurement (볼트 체결력 측정을 위해 제안한 커브피팅 알고리즘에 관한 연구)

  • Lee, Ki-Won
    • Journal of Satellite, Information and Communications
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    • v.7 no.3
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    • pp.94-98
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    • 2012
  • In order to serve the exact torque clamping force, the torque measurement system use the curve fitting algorithm by the least square. The corrected least square curve fitting algorithm which suggested in this paper can surpport more exact clamping force for fastner in variable industry field using the torque. At first, This paper introduces mathematical modeling for curve fitting algorithm, and simulate it. As a result, the corrected least square algorithm have shown lower standard error value than that of the used algoritm with torque, and so this corrected least square algorithm prove high accuracy than nomal least square algorithm. The suggested algorithm will contribute to improvement of cost and safety on industry field with bolt clamping force for precision industry parts, electronics parts, aircraft, aerospace, etc.

An electromechanical impedance-based method for tensile force estimation and damage diagnosis of post-tensioning systems

  • Min, Jiyoung;Yun, Chung-Bang;Hong, Jung-Wuk
    • Smart Structures and Systems
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    • v.17 no.1
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    • pp.107-122
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    • 2016
  • We propose an effective methodology using electromechanical impedance characteristics for estimating the remaining tensile force of tendons and simultaneously detecting damages of the anchorage blocks. Once one piezoelectric patch is attached on the anchor head and the other is bonded on the bearing plate, impedance responses are measured through these two patches under varying tensile force conditions. Then statistical indices are calculated from the impedances, and two types of relationship curves between the tensile force and the statistical index (TE Curve) and between statistical indices of two patches (SR Curve) are established. Those are considered as database for monitoring both the tendon and the anchorage system. If damage exists on the bearing plate, the statistical index of patch on the bearing plate would be out of bounds of the SR curve and damage can be detected. A change in the statistical index by damage is calibrated with the SR curve, and the tensile force can be estimated with the corrected index and the TE Curve. For validation of the developed methodology, experimental studies are performed on the scaled model of an anchorage system that is simplified only with 3 solid wedges, a 3-hole anchor head, and a bearing plate. Then, the methodology is applied to a real scale anchorage system that has 19 strands, wedges, an anchor head, a bearing plate, and a steel duct. It is observed that the proposed scheme gives quite accurate estimation of the remaining tensile forces. Therefore, this methodology has great potential for practical use to evaluate the remaining tensile forces and damage status in the post-tensioned structural members.

Analysis on Wheel Load and Lateral Force in Curve Section Between the Boost and Traction Driving Mode (추진운전 및 견인운전에 따른 곡선부 궤도부담력 비교 분석)

  • Lee, Syeung-Youl;Kim, Nam-Hong;Lee, Seok-Young
    • Proceedings of the KSR Conference
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    • 2011.10a
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    • pp.365-373
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    • 2011
  • In general, when train drives boost and traction mode, force of delivering to the track was difference between boost and traction driving mode. But, in korea, we've never performed that measure the track wheel load and lateral force while boost and traction driving. This study measured wheel load and lateral force using combination of 7200type locomotive and six freight car. And the train used single and automatic brake. The train drives boost and traction mode. In order to the difference radius of curve, we had measured at 3 point in the curve of turnout.

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Product Analysis and Appearance Evaluation of a Sleeve Head for the Aesthetic Exterior of a Jacket Sleeve (재킷 소매의 심미적 외관을 위한 슬리브헤드의 제품분석 및 외관평가)

  • Park, Youngja;Jang, Jeongah
    • Journal of the Korean Society of Clothing and Textiles
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    • v.39 no.6
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    • pp.852-866
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    • 2015
  • This study analyzes the form of sleeve heads, which is an important internal element that affects the appearance of jacket sleeves. It characterized sleeve head forms by investigating angles, materials, and a combination of formations for 50 sleeve heads. It conducted an appearance evaluation by comparing and analyzing the results. This paper develops a sleeve head appropriately for sleeve construction. The study results are as follows. First, the product was divided into three parts: based on, force receiving, and sleeve cap parts. There were four types of man's sleeve head: straight, arc, and curve A and B types. The woman's sleeve head had two types: straight and curve B type. Second, the feature of each type of sleeve head was analyzed. A straight type emphasized the based on part. An arc type highlighted the force receiving part while the based on part decreased. The sleeve cap part, force receiving part, and based on part were emphasized in the arc type sleeve head. Third, as a result of the appearance evaluation, each type was rank as straight type < arc type ${\leq}$ curve A < curve B. The straight type did not get positive results as it had extra ease when the sleeve head was attached to a Jacket Sleeve. The arc type was evaluated poorly due to an inappropriate sleeve cap composition. The curve type received an excellent overall outcome as it fit into the sleeve cap part well and highlighted the force receiving part in order to minimize front and back wrinkles. Therefore, the curve type made the resemblance of the jacket appearance perfect and closest to the sleeve pattern.

Development of Clamping Force Estimation Algorithm and Clamp-force Sensor Calibration on Electromechanical Brake Systems (전동식 브레이크 시스템의 클램핑력 센서 교정 및 클램핑력 추정 알고리즘 개발)

  • Park, Giseo;Choi, Seibum;Hyun, Dongyoon
    • Transactions of the Korean Society of Automotive Engineers
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    • v.24 no.3
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    • pp.365-371
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    • 2016
  • The electromechanical brake (EMB) is one of future brake systems due to its many advantages. For implementation of the EMB, the correct feed back about clamping force is necessary. Keeping commercialization of the EMB in mind, it is strongly demanded that an expensive load cell measuring the clamping force is replaced with an estimation algorithm. In addition, an estimation of the kissing point where the brake pads start to come into contact with a disk wheel is proposed in this paper. With these estimation algorithms, the clamping force can be expressed as a polynomial characteristic curve versus the motor angle. Also, a method for calibration of measured values by the load cell is proposed and used for an actual characteristic curve. Lastly, the performance of the proposed algorithms is evaluated in comparison with the actual curve on a developed EMB test bench.

Nanomechanical Properties Analysis on Polymer Blend Surfaces by Atomic Force Microscopy

  • Fujinami, So;Nakajima, Ken;Nishi, Toshio
    • Proceedings of the Polymer Society of Korea Conference
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    • 2006.10a
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    • pp.340-340
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    • 2006
  • Applying force-distance curve measurement by atomic force microscopy to a theoretical mechanical model gives us elastic properties of polymer surfaces. Our group focuses on force-mapping method, in which force-distance curve is performed at each lattice point on a sample surface and subsequently a variety of properties derived from analytical results are combined to construct a 2-dimensional image. With this method we succeeded in deriving Young' s modulus distribution map method of rubbery/rubbery polymer blend surfaces with ${\sim}100\;nm$ lateral resolution. We also applied force-mapping method to another theory to divide distribution of hardness from that of adhesion. We will demonstrate recent progress.

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Friction Characterization of Feed Drive Systems using Feed Motor Current (이송전류신호를 이용한 이송계의 마찰특성에 관한 연구)

  • 김기대;조현우;주종남
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1994.10a
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    • pp.249-253
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    • 1994
  • In machine tools, frictional force exists between the table and the bed, and in ballscrews. In this paper, feed motor current is used to measure the motor torque and frictional force. A hall sensor is used to measure the feed motor current. Some frictional pheonomina in feed drice systems, such as, the relationship between feedrate and frictional force, lubrication conditions and frictional force, and feed direction and frictional force, are obtained. Generally, the friction behavior is in good agreement with Stribeck's curve. However, the data shows significant scatter when feedrate is high.

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Isolated RC wall subjected to biaxial bending moment and axial force

  • Park, Honggun
    • Structural Engineering and Mechanics
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    • v.9 no.5
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    • pp.469-482
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    • 2000
  • A numerical study using nonlinear finite element analysis is performed to investigate the behavior of isolated reinforced concrete walls subjected to combined axial force and in-plane and out-of-plane bending moments. For a nonlinear finite element analysis, a computer program addressing material and geometric nonlinearities was developed. Through numerical studies, the internal force distribution in the cross-section is idealized, and then a new design method, different from the existing methods based on the plane section hypothesis was developed. According to the proposed method, variations in the interaction curve of the in-plane bending moment and axial force depends on the range of the permissible axial force per unit length, that is determined by a given amount of out-of-plane bending moment. As the out-of-plane bending moment increases, the interaction curve shrinks, indicating a decrease in the ultimate strength. The proposed method is then compared with an existing method, using the plane section hypothesis. Compared with the proposed method, the existing method overestimates the ultimate strength for the walls subjected to low out-of-plane bending moments, while it underestimates the ultimate strength for walls subject to high out-of-plane bending moments. The proposed method can address the out-of-plane local behavior of the individual wall segments that may govern the ultimate strength of the entire wall.

Characterization of Supported Lipid Layers Using Atomic Force Microscopy (원자힘현미경을 이용한 지지 지질층의 특성규명)

  • Park, Jin-Won
    • Korean Chemical Engineering Research
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    • v.47 no.4
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    • pp.395-402
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    • 2009
  • The atomic force microscopy(AFM) has been used, as a powerful tool, to investigate physical properties of supported-lipid layers. Prior to the advent of the AFM, no observation was performed for the physical phenomena at the nanometer-scale. This microscope provides nanometer-scale morphology by scanning surfaces with the cantilever and presents force curve by monitoring the behavior of the cantilever that approaches to surface and retracts from the surface. From the morphology, the structures of the supported lipid layer and the effect of other molecules on the structures have been investigated. From the force curve, the surface properties-electrostatic and mechanical properties-of the supported lipid layers have been studied. In this article, characterization of the structure and surface properties of the supported lipid layer is explained. Future perspectives and direction are also discussed.