• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1143-1147
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• 2008

This test is performed to reduce slip/slide which are generated from VVVF inverter. when the adhesive force between wheel and rail is not ensured, slip/slide are mainly originated. In this paper, we carried out real test adopting acceleration changes to find optimized method minimizing the amount of generation of slip/slide. Through this real test, we obtained optimum result on reducing slip/slide and especially focused on decrease in slip. This method is currently applied to real train.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.420-424
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• 1997

n the ballscrew slide system the ~najor problems in accomplishing the high-speed and high-precision are the friction between elements and the decrease of axial stiffness. Especially the friction on the guide have a bad effect on the precision of slidlng. Furthermore stick-slip occur when the low stiffness of slide system. The sticli-slip have a bad influence on the precision. In this research, the affection of stick-slip friction to the precision of the slide system is studied and the possible solution of the precision is proixjsed.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.377-383
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• 2011

The paper is to perceive accurately speed of the train through redundant processor operation. When Slip/slide is occurred at the axle, the train is applied brake force using the Tachometer and the Doppler sensor which assistance equipment. One of the main features of railway signaling system is that rolling stock is made stop to avoid collision with the rolling stock ahead when the rolling stock exceeds its maximum operating speed in line. In addition, in the case of the rolling stock with automatic train operation, it carries out activities such as braking and propulsion using the difference between its actual speed and target speed at the point. To perform these functions, it is essential to calculate the exact speed of the rolling stock in signaling equipment on vehicles. Train speed detection unit are composed of the Tachometer and the Doppler sensor, and speed information is sent to the SDU unit. The processor of SDU unit calculates the speed of the train using compare logic the received speed information. Even if there are Slip/Slide, signaling system is available to apply exact braking, to improve stop on position and to guarantee the safety of trains.

• Structural Engineering and Mechanics
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• v.32 no.2
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• pp.251-267
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• 2009

Reinforced concrete (RC) structures consist of two different materials: concrete and steel bar. The stress transfer behaviour between the two materials through bond plays an important role in the load-carrying capacity of RC structures, especially when they subject to lateral load such as blast and seismic load. Therefore, bond and slip between concrete and reinforcement bar will affect the response of RC structures under such loads. However, in most numerical analyses of blast-induced structural responses, the perfect bond between concrete and steel bar is often assumed. The main reason is that it is very difficult to model bond slip in the commercial finite element software, especially in hydrodynamic codes. In the present study, a one-dimensional slide line contact model in LS-DYNA for modeling sliding of rebar along a string of concrete nodes is creatively used to model the bond slip between concrete and steel bars in RC structures. In order to model the bond slip accurately, a new approach to define the parameters of the one-dimensional slide line model from common pullout test data is proposed. Reliability and accuracy of the proposed approach and the one-dimensional slide line in modelling the bond slip between concrete and steel bar are demonstrated through comparison of numerical results and experimental data. A case study is then carried out to investigate the bond slip effect on numerical analysis of blast-induced responses of a RC column. Parametric studies are also conducted to investigate the effect of bond shear modulus, maximum elastic slip strain, and damage curve exponential coefficient on blast-induced response of RC columns. Finally, recommendations are given for modelling the bond slip in numerical analysis of blast-induced responses of RC columns.

• Journal of Korean Association for Spatial Structures
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• v.22 no.4
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• pp.99-107
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• 2022

Existing reinforced concrete building structures constructed before 1988 have seismically-deficient reinforcing details, which can lead to the premature failure of the columns and beam-column joints. The premature failure was resulted from the inadequate bonding performance between the reinforcing bars and surrounding concrete on the main structural elements. This paper aims to quantify the bond-slip effect on the dynamic responses of reinforced concrete frame models using finite element analyses. The bond-slip behavior was modeled using an one-dimensional slide line model in LS-DYNA. The bond-slip models were varied with the bonding conditions and failure modes, and implemented to the well-validated finite element models. The dynamic responses of the frame models with the several bonding conditions were compared to the validated models reproducing the actual behavior. It verifies that the bond-slip effects significantly affected the dynamic responses of the reinforced concrete building structures.

• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.1879-1880
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• 2006

In electric motor coaches, when the adhesion force between rail and driving wheel decreases suddenly, the electric motor coach has slip phenomena. The characteristics of adhesion force coefficient is strongly affected by the conditions between rails and driving wheels, such as moisture, dust, and oil on the rails and so on. This paper proposes the simulation system for slip & slide test using virtual train. We can easily research the adhesion characteristics and adhesion control method with this equipment under the sudden variation of the adhesion force coefficient.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.6
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• pp.88-98
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• 2014

A moving mass on a skewed linear guideway model to analyze the friction-induced stick-slip behavior of ball-screw-driven slides is proposed. To describe the friction force, a friction coefficient function is modelled as a third-order polynomial of the relative velocity between the slide mass and a guideway. A nonlinear differential equation of motion is derived and an approximate solution is obtained using a perturbation method for the amplitudes and base frequencies of both pure-slip and stick-slip oscillations. The results are presented with time responses, phase plots, and amplitude plots, which are compared adequately with those obtained by Runge Kutta 4th-order numerical integration, as long as the difference between the static and kinematic friction coefficients is small. However, errors in the results by the approximate solution increase and are not negligible if the difference between the friction coefficients exceeds approximately 40% of the static friction coefficient.

• Journal of Electrical Engineering and Technology
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• v.10 no.1
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• pp.429-435
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• 2015

This study proposes a re-adhesion algorithm that has stable traction effort for rolling stock slip/slide minimization when deliverable traction decreases by slip. The proposed scheme estimates appropriate reference speed using two encoders for reducing slip and controls traction effort stably and has stable control characteristics for disturbance. The algorithm which uses the maximum adhesive effort by instantaneous estimation of adhesion force stably controls traction effort and gives rolling stock excellent acceleration and deceleration characteristics. And a slip sensing element that can quickly detect slip is used. Load motor and inverter were checked in various slip conditions for creating various line conditions.

• 한국기계연구소 소보
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• s.18
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• pp.29-35
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• 1988

When low sliding velocities in the boundary lubrication range are operating, irregular movements frequently occur which are a result of the stick-slip phenomenon. Such slide motions are undesirable in precision machine tools, particularly with feed back systems used in numerical and adaptive control machine tools. Accordingly, this paper reports analytical and experimental studies in the stick-slip characteristic of machine tool feeding system. The main conclusions of this study are as follows; The tendency towards stick-slip effects may be reduced by; 1). Reducing the drop in friction coefficient in the Stribeck curve(on the rising part of the friction characteristic at higher sliding speeds, the system is stable all the time) 2). Reducing the transition velocity by the use of a higher viscosity lubricating oil. 3). Increasing the stiffness(Damping)and reducing normal load(Sliding mass) Therefore, the Critical velocity is decided from the above conclusions and in designing of machine tool, feed rates(sliding velocity)must be design the more than critical velocity.

• Multiscale and Multiphysics Mechanics
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• v.1 no.3
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• pp.261-270
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• 2016

The longitudinal velocity (forward speed) having significant importance in proper running of railway wheelset on track, depends greatly upon the adhesion ratio and creep analysis by implementation of suitable dynamic system on contamination. The wet track condition causes slip and slide of vehicle on railway tracking, whereas high speed may also increase slip and skidding to severe wear and deterioration of mechanical parts. The basic aim of this research is to design appropriate model aimed estimator that can be used to control railway vehicle forward velocity to avoid slip. For the filtration of disturbance procured during running of vehicle, the kalman filter is applied to estimate the actual signal on preferered samples of creep co-efficient for observing the applied attitude of noise. Thus error level is detected on higher and lower co-efficient of creep to analyze adhesion to avoid slip and sliding. The skidding is usually occurred due to higher forward speed owing to procured disturbance. This paper guides to minimize the noise and error based upon creep coefficient.