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Chen M.,Tongji University | Luo Y.Y.,Tongji University | Zhang B.,China Railway Shanghai Design Institute Group Co.
Advanced Materials Research

Finite element model of track in frog zone is built by vehicle-turnout system dynamics. Considering variation of rail section and elastic support, bending deformation of turnout sleeper, spacer block and sharing pad effects, the track integral rigidity distribution in longitudinal direction is calculated in the model. Vehicle-turnout rigid-flexible coupling model is built by finite element method (FEM), multi-body system (MBS) dynamics and Hertz contact theory. With the regularity solution that different stiffness is applied for rubber pad under sharing pad of different turnout sleeper zone, analysis the variation of vertical acceleration of bogie and wheelset, rail vertical displacement and wheel-rail interaction force, this paper proves that setting reasonable rubber pad stiffness is an efficient method to solve rigidity irregularity problem. © (2014) Trans Tech Publications, Switzerland. Source

Gui Y.,Kunming University of Science and Technology | Zhang Q.,Kunming University of Science and Technology | Wei H.,Kunming University of Science and Technology | Wang Q.,China Railway Shanghai Design Institute Group Co. | Yhang H.,General Engineering Company
Applied Mechanics and Materials

The paper presents a comparative study of particle size analyses of quicklime-stabilized dredged material (LSDM) by combined sieve-hydrometer method (SHM), laser diffraction method (LDM) and sieve method (SM). After analyzed the testing processes and compared the results comprehensively, some conclusions can be conduction. Adopting SHM and LDM to test the particle size of LSDM, not only break the structure unit of soil, but also change its property due to the pure water used as disperser. In addition, the severe flocculation, which attributed to the dissolvable salt in soil introduced by quicklime can't be drainage effectively, result in the abnormal particle size distribution (PSD) curves produced by the SHM. Therefore, SHM and LDM are not suitable for the particle size analyses of LSDM. SM, without deteriorating the unit structure of aggregates and altering the properties of soil, should be adopted as the most suitable method for LSDM © (2012) Trans Tech Publications, Switzerland. Source

Zhu D.,Lanzhou Jiaotong University | Zhu D.,China Railway Shanghai Design Institute Group Co. | Zhang Y.,Lanzhou Jiaotong University | Lin L.,Lanzhou Jiaotong University | Wang L.,Lanzhou Jiaotong University
Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology)

A special-support box girder element was presented to analyze the torsional mechanical behavior of the continuous box girder bridge with special supports. The deformations of axial extension, vertical bending and restraint torsion were considered in the element. The displacements at the beam axis were transformed to the special support point by introducing the element displacement transformation matrix to satisfy the displacement constraint condition at the special support section. The homogeneous solution to the restraint torsion differential equation was adopted as the torsional displacement function of the element and the element stiffness matrix for restraint torsion was derived by applying the initial parameter solution. A three-span continuous box girder model with special supports was analyzed by using the element presented and the calculated results of stresses are in good agreement with the shell element results of ANSYS and the testing results, which verifies the effectiveness of the box girder element. The torsional mechanical behaviors of the continuous box girder with special supports and the corresponding regular box girder under eccentric load were analyzed in detail. The results show that the torque moment, bi-moment, torsion angle and generalized warping displacement of the box girder with special supports are larger than those of the corresponding regular box girder. The distribution of the internal force and displacement of the box girder with special supports is more complicated than that of the regular box girder. © 2016, Central South University of Technology. All right reserved. Source

Wei H.,Kunming University of Science and Technology | Yang H.,Kunming University of Science and Technology | Tian D.-P.,Yunnan Geological Investigation Group CO. | Wang Q.-H.,China Railway Shanghai Design Institute Group Co.
Advanced Materials Research

Dam deformation is characterized with periodicity, tendency, randomicity. So dam deformation can be regarded as sum of periodic deformation, tendency deformation, and random deformation, of which periodic and tendency deformation, gained by deterministic method, are researched sufficiently, but study on random deformation is inadequacy. Because dam random deformation at time t is mainly influenced by dam state at time t-1, little influenced at time t-2 or earlier, dam random deformation can be idealized as stochastic process described by Markov chain. In this paper, a new dam safety monitoring model is established using Markov chain, based on statistic model. First, regression analysis was applied to establish dam deformation statistic model, by which dam deterministic deformation can be obtained. Then dam random deformation component can be gained by subtracting deterministic deformation from total dam deformation. Consequently, by analysis of time series of random deformation, transition probability matrix of random deformation can be obtained and used to analyze dam deformation. Case study showed that this new model is superior to traditional statistic model, and can be applied to establish dam safety monitoring model. © (2011) Trans Tech Publications, Switzerland. Source

He X.,Southwest Jiaotong University | Guo A.,Southwest Jiaotong University | Peng X.,Southwest Jiaotong University | Zhou Y.,China Railway Shanghai Design Institute Group Co. | And 2 more authors.

The advanced traction power supply system (ATPSS) is a new directional development for traction power supply systems, which can totally remove the neutral sections and effectively promote power quality. However, the existing converters suffer from small substation capacity. In this paper, a new configuration based on a three-level neutral point clamped (3L-NPC) three-phase to single-phase cascade converter in a substation is proposed for ATPSS, which can be used to match the capacity of the converter for high voltage and large power applications. The control strategy of the proposed converter is analyzed in depth, and the phase disposition sinusoidal pulse width modulation (PD-SPWM) with phase shift carrier SPWM (PSC-SPWM) is employed in the inverters. Then, the inductance equalizing circuit is applied for the voltage balance on the DC-link. Besides, a LC filter circuit is designed to eliminate the double line-frequency ripple of DC voltage. Afterwards, a simulation model and an experimental prototype are developed, respectively. The simulation results show that the proposed converter in this paper can not only meet the requirements of voltage and capacity for the traction network, but also improve power quality. Finally, the experimental results verify the correctness and feasibility of the proposed control strategy. © 2015 by the authors. Source

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