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Mechanics model of additional longitudinal force transmission between bridges and continuously welded rails with small resistance fasteners 被引量:11
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作者 徐庆元 周小林 +1 位作者 曾志平 杨小礼 《Journal of Central South University of Technology》 2004年第3期336-339,共4页
A new mechanics model, which reveals additional longitudinal force transmission between the continuously welded rails and the bridges, is established on the fact that the influence of the mutual relative displacement ... A new mechanics model, which reveals additional longitudinal force transmission between the continuously welded rails and the bridges, is established on the fact that the influence of the mutual relative displacement (among) the rail, the sleeper and the beam is taken into account. An example is presented and numerical results are compared. The results show that the additional longitudinal forces calculated with the new model are less than those of the previous, especially in the case of the flexible pier bridges. The new model is also suitable for the analysis of the additional longitudinal force transmission between rails and bridges of ballastless track with small resistance fasteners without taking the sleeper displacement into account, and compared with the ballast bridges, the ballastless bridges have a much stronger additional longitudinal force transmission between the continuously welded rails and the bridges. 展开更多
关键词 railway engineering continuously welded rails on bridge additional longitudinal force mechanics model
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Fuzzy Sliding Mode Control Based on Longitudinal Force Estimation for Electro-mechanical Braking Systems using BLDC Motor 被引量:4
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作者 Xiaoyan Peng Mingfei Jia +2 位作者 Lei He Xiang Yu Yibin Lv 《CES Transactions on Electrical Machines and Systems》 2018年第1期142-151,共10页
This paper focuses on the controller design using fuzzy sliding mode control(FSMC)with application to electro-mechanical brake(EMB)systems using BLDC Motor.The EMB controller transmits the control signal to the motor ... This paper focuses on the controller design using fuzzy sliding mode control(FSMC)with application to electro-mechanical brake(EMB)systems using BLDC Motor.The EMB controller transmits the control signal to the motor driver to rotate the motor.The torque distribution of motors is studied in this paper actually.Firstly,the model of the EMB system is established.Then the state observer is developed to estimate the vehicle states including the vehicle velocity and longitudinal force.Due to the fact that the EMB system is nonlinear and uncertain,a FSMC strategy based on wheel slip ratio is proposed,where both the normal and emergency braking conditions are taken into account.The equivalent control law of sliding mode controller is designed on the basis of the variation of the front axle and rear axle load during the brake process,while the switching control law is adjusted by the fuzzy corrector.The simulation results illustrate that the FSMC strategy has the superior performance,better adaptability to various types of roads,and shorter braking distance,as compared to PID control and traditional sliding mode control technologies.Finally,the hardware-in-loop(HIL)experimental results have exemplified the validation of the developed methodology. 展开更多
关键词 BLDC Motor electro-mechanical brake fuzzy sliding mode control longitudinal force estimation hardware-in-loop experiments wheel slip ratio
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The Use of Tamping Machine for Diagnosising the Longitudinal Forces in Rails of CWR Track
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作者 Wladyslaw Koc Andrzej Wilk +1 位作者 Slawomir Grulkowski Piotr Chrostowski 《Journal of Civil Engineering and Architecture》 2010年第11期11-25,共15页
In the novel approach to the diagnostic tests of continuous welded rail (CWR) track by the use of the tamping machine, the fundamental statement related to the recording of the curvature with a definite value of the... In the novel approach to the diagnostic tests of continuous welded rail (CWR) track by the use of the tamping machine, the fundamental statement related to the recording of the curvature with a definite value of the lateral displacement being subjected to verification, can provide a basis for the determination of the longitudinal axial force in the rail. An attempt has also been made to define an alternative factor which by means of the measured signals, could be used for the determination of the axial forces in the rail sections. A power engineering approach has been adopted to this concept. Within the framework of the experimental investigations, measurements were carried out in the track test section. The investigations were based on stretching the rail sections by stretchers and on lateral displacements of the track by the tamping machine. The operation of the measuring apparatus was also tested in the experimental railway track section while carrying out the geometrical adjustments by the tamping machine. As a result of next series of the investigation carried out in 2006-2007, the authors worked out a procedure of estimating the longitudinal forces in rails of CWR track. 展开更多
关键词 CWR track longitudinal forces lateral displacements tamping machine measuring apparatus.
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On chip chiral and plasmonic hybrid dimer or tetramer:Generic way to reverse longitudinal and lateral optical binding forces
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作者 Sudipta Biswas Roksana Khanam Rumi +2 位作者 Tasnia Rahman Raima Saikat Chandra Das M R C Mahdy 《Chinese Physics B》 SCIE EI CAS CSCD 2022年第5期305-316,共12页
For both the longitudinal binding force and the lateral binding force,a generic way of controlling the mutual attraction and repulsion(usually referred to as reversal of optical binding force)between chiral and plasmo... For both the longitudinal binding force and the lateral binding force,a generic way of controlling the mutual attraction and repulsion(usually referred to as reversal of optical binding force)between chiral and plasmonic hybrid dimers or tetramers has not been reported so far.In this paper,by using a simple plane wave and an onchip configuration,we propose a possible generic way to control the binding force for such hybrid objects in both the near-field region and the far-field region.We also investigate different inter-particle distances while varying the wavelengths of light for each inter-particle distance throughout the investigations.First of all,for the case of longitudinal binding force,we find that chiral-plasmonic hybrid dimer pairs do not exhibit any reversal of optical binding force in the near-field region nor in the far-field region when the wavelength of light is varied in an air medium.However,when the same hybrid system of nanoparticles is placed over a plasmonic substrate,a possible chip,it is possible to achieve a reversal of the longitudinal optical binding force.Later,for the case of lateral optical binding force,we investigate a setup where we place the chiral and plasmonic tetramers on a plasmonic substrate by using two chiral nanoparticles and two plasmonic nanoparticles,with the setup illuminated by a circularly polarized plane wave.By applying the left-handed and the right-handed circular polarization state of light,we also observe the near-field and the far-field reversal of lateral optical binding force for both cases.As far as we know,so far,no work has been reported in the literature on the generic way of reversing the longitudinal optical binding force and the lateral optical binding force of such hybrid objects.Such a generic way of controlling optical binding forces can have important applications in different fields of science and technology in the near future. 展开更多
关键词 longitudinal binding force PLASMONICS CHIRALITY optical force
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Applicability of small resistance fastener on long-span continuous bridges of high-speed railway 被引量:19
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作者 戴公连 刘文硕 《Journal of Central South University》 SCIE EI CAS 2013年第5期1426-1433,共8页
Ballastless tracks have been widely applied in high-speed railway (HSR). The adaptability research between continuous welded rails (CWR) and long-span bridges of HSR is of great practical engineering significance. Bas... Ballastless tracks have been widely applied in high-speed railway (HSR). The adaptability research between continuous welded rails (CWR) and long-span bridges of HSR is of great practical engineering significance. Based on the HSR long-span continuous bridges, the integrative spatial finite element model of track-bridge-pier-foundation system was established with the nonlinear spring element simulating the longitudinal resistance between track and bridge. Comparative study on the various additional longitudinal forces of CWR using the common fasteners and small resistance fasteners was carried out. Analysis results indicate that the additional expansion forces and additional rail-breaking forces in long-span ballastless continuous girders can be reduced evidently by 40% 50% after adopting small resistance fasteners, but lead to greater rail broken gap. The small resistance fasteners have little influence on the additional force only caused by vertical load, but can reduce the additional force caused by vertical load combined with braking load by over 10%. Besides, transient analysis method is proved to be more accurate and safe in calculating additional longitudinal forces when the train running or braking on the bridge, compared with the traditional static method. 展开更多
关键词 ballastless track small resistance fasteners additional longitudinal force long-span continuous beam high-speed railway
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Beam-track interaction of high-speed railway bridge with ballast track 被引量:18
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作者 闫斌 戴公连 张华平 《Journal of Central South University》 SCIE EI CAS 2012年第5期1447-1453,共7页
Based on the construction bridge of Xiamen-Shenzhen high-speed railway(9-32 m simply-supported beam + 6×32 m continuous beam),the pier-beam-track finite element model,where the continuous beam of the ballast trac... Based on the construction bridge of Xiamen-Shenzhen high-speed railway(9-32 m simply-supported beam + 6×32 m continuous beam),the pier-beam-track finite element model,where the continuous beam of the ballast track and simply-supported beam are combined with each other,was established.The laws of the track stress,the pier longitudinal stress and the beam-track relative displacement were analyzed.The results show that reducing the longitudinal resistance can effectively reduce the track stress and the pier stress of the continuous beam,and increase the beam-track relative displacement.Increasing the rigid pier stiffness of continuous beam can reduce the track braking stress,increase the pier longitudinal stress and reduce the beam-track relative displacement,Increasing the rigid pier stiffness of simply-supported beam can reduce the track braking stress,the rigid pier longitudinal stress and the beam-track relative displacement. 展开更多
关键词 high-speed railway beam-track interaction ballast track rail longitudinal force continuous beam
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A new device for stress monitoring in continuously welded rails using bi-directional strain method 被引量:1
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作者 Ganzhong Liu Hao Liu +3 位作者 Anqi Wei Jieling Xiao Ping Wang Shaozheng Li 《Journal of Modern Transportation》 2018年第3期179-188,共10页
The technology of continuously welded rails (CWRs) is important in modern railway track structures. To measure rail stress, resistance strain gauges are preferred due to their good stability, sensitivity, and esist... The technology of continuously welded rails (CWRs) is important in modern railway track structures. To measure rail stress, resistance strain gauges are preferred due to their good stability, sensitivity, and esistance to external interference. Based on the bi-directional strain method, we present a new method for measuring longitudinal rail stress using resistance strain gauges and develop a monitoring device for rail stress to realize long-term and multi-point measurement. Also relevant experimental verification and analysis are conducted. Results indicate that under various constraints the rail stress–strain values can be calculated just with the measured total longitudinal strain and total vertical strain. Considering the measurement error caused by sectional feature of sensors, we put forward a correction equation applicable to different stress conditions. Although the temperature values of the four full-bridge stress gauges can offset each other, the measurement error caused by rail flexural strain can also be eliminated to a certain extent at the same time, the nonuniform distribution of rail cross section temperature and unbalanced flexural strain still affect the measurement error. The experimental results also show that the developed rail-stress-monitoring sensor is suitable for measuring rail stress with reliable working performance. 展开更多
关键词 Resistance strain gauge Continuously weldedrail longitudinal force in rail Bi-directional strainmethod Monitoring instrument
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Determination of complex Young's modulus of viscoelastic bars using forced longitudinal vibration of slender rods 被引量:4
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作者 HE Xiping Avraham Benatar 《Chinese Journal of Acoustics》 2013年第1期63-70,共8页
A method to identify complex Young's modulus of viscoelastic materials using forced longitudinal vibration of slender rods is proposed. The method differs from the beam one. Experimental tests were carried out at roo... A method to identify complex Young's modulus of viscoelastic materials using forced longitudinal vibration of slender rods is proposed. The method differs from the beam one. Experimental tests were carried out at room temperature with different lengths in 108 mm, 100 mm, 90 ram, 83.5 mm, 80 ram, 74.5 mm, 70 mm for the polycarbonate bars, and the curves of ratios A2/A1 between two ends of a viscoelastic bar versus frequencies are obtained, furthermore, the corresponding 3 dB bandwidth and the storage and loss modulus can be calculated. Sufficient number of obtained complex Young's modulus at different frequency allows us to calculate other ones using the least square method. If the step of the tested frequency is 5 Hz, the maximum error of results can be less than 6%. By comparison with the measurement methods which the previous literature mentioned, this new method simplifies the calculation, and the physical meaning appears apparently and clearly. 展开更多
关键词 Determination of complex Young’s modulus of viscoelastic bars using forced longitudinal vibration of slender rods AZ KHZ
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Structured Estimation of Tire Forces and the Ground Slope Using SM Observers
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作者 Belgacem Jaballah Nacer Kouider M'Sirdi 《International Journal of Automation and computing》 EI CSCD 2014年第2期197-204,共8页
In agricultural context, the principal cause of serious accidents for all-terrain vehicles(ATVs) is rollover. The most important parameters related to this risk is the ground slope. In this paper, we propose a structu... In agricultural context, the principal cause of serious accidents for all-terrain vehicles(ATVs) is rollover. The most important parameters related to this risk is the ground slope. In this paper, we propose a structured observer to estimate the system states and the longitudinal tire forces using only wheel angular velocities measurement. The robust estimation is based on a second order sliding mode observer. This estimation is then used to build up a ground slope estimation. The algorithm is composed by two cascaded estimators. This structured estimation is then applied to the model of an agricultural vehicle G7(GregoireTM) integrated in the driving simulation environment SCANeRTM-Studio. 展开更多
关键词 All-terrain vehicles rollover situation sliding modes observers longitudinal tire forces ground slope.
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