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STUDY ON DYNAMIC CURVING BEHAVIOR OF TILTING PASSENGER CARS

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Chinese Journal of Mechanical Engineering 2002年第4期15卷 360-365,371页

作者： Liu Hongyou Zeng Jing national Traction Power laboratory, Southwest Jiaotong University, chengdu 610031, china national Traction Power laboratory Southwest Jiaotong University Chengdu 610031 China

By using tilting carbodies, train can negotiate at a higher speed withoutreducing the passenger's ride quality. This is a good method to allow a significant increase inspeed at existing track to improve the railway transportation capability, and to enhance thecompetition ability of railways with other transportation systems. With the increase of the curvenegotiation speed, the wheel-rail lateral forces and wheel-rail wear of the tilting train willincrease. The self-steering radial bogie is an effective way to solve the problem. The dynamic modelof the tilting passenger car with self-steering bogies is established in detail, and the curvingperformance of the car is investigated.

关键词： tilting passenger car self-steering bogie dynamic curving behavior wheel-rail interaction

Constructing globally consecutive 3D conductive network using P-doped biochar cotton fiber for superior performance of silicon-based anodes

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Journal of Materials Science & Technology 2024年第6期173卷 181-191页

作者： Jun Cao Jianhong Gao Kun Wang Zhuoying Wu Xinxin Zhu Han Li Min Ling chengdu Liang Jun Chen Zhejiang Provincial Key laboratory of Advanced Chemical Engineering Manufacture Technology College of Chemical and Biological EngineeringZhejiang UniversityHangzhou 310027China Institute of Zhejiang University-Quzhou Zheda Road 99Quzhou 324000China

The inferior conductivity and drastic volume expansion of silicon still remain the bottleneck in achieving high energy density Lithium-ion Batteries(LIBs).The design of the three-dimensional structure of electrodes by compositing silicon and carbon materials has been employed to tackle the above challenges,however,the exorbitant costs and the uncertainty of the conductive structure persist,leaving ample room for ***,silicon nanoparticles were innovatively composited with eco-friendly biochar sourced from cotton to fabricate a 3D globally consecutive conductive *** network serves a dual purpose:enhancing overall electrode conductivity and serving as a scaffold to maintain electrode *** conductivity of the network was further augmented by introducing P-doping at the optimum doping temperature of 350℃.Unlike the local conductive sites formed by the mere mixing of silicon and conductive agents,the consecutive network can affirm the improvement of the conductivity at a macro ***,first-principle calculations further validated that the rapid diffusion of Li^(+)is attributed to the tailored electronic microstructure and charge rearrangement of the *** prepared consecutive conductive Si@P-doped carbonized cotton fiber anode outperforms the inconsecutive Si@Graphite anode in both cycling performance(capacity retention of 1777.15 mAh g^(-1) vs.682.56 mAh g^(-1) after 150 cycles at 0.3 C)and rate performance(1244.24 mAh g^(-1) vs.370.28 mAh g^(-1) at 2.0 C).The findings of this study may open up new avenues for the development of globally interconnected conductive networks in Si-based anodes,thereby enabling the fabrication of high-performance LIBs.

关键词： 3D conductive network Biochar carbon-silicon anode Heteroatoms doping strategy DFT calculation Lithium-ion battery

ELASTIC-PLASTIC FINITE ELEMENT ANALYSIS OF THREE-DIMENSIONAL CONTACT-IMPACT AT rail JOINT

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Chinese Journal of Mechanical Engineering 2003年第4期16卷 411-416页

作者： Wen ZefengJin XuesongZhang Weihuanational Traction Power laboratory,Southwest Jiaotong University,chengdu 610031, china Southwest Jiaotong University National Traction Power Laboratory Chengdu 610031

Using the finite element code ANSYS/LS-DYNA, a dynamic finite element modelwith an elastic-linear-kinematic-hardening plastic material is established to analyzeelastic-plastic stresses in the railhead in the impact process of wheel and rail occurring at thegap of rail joint. The model is based on the discrete elastic support condition of the rails, whichis suitable for the actual situation of wheel/track rolling contact. In the analysis the influencesof axle load, yield stress and tangent modulus of rail material on the stresses and strains areinvestigated in detail. The distribution of stresses and strains in the jointed railhead are *** is found that the axle load, yield stress and tangent modulus of rail material greatly affect thestresses and strains in the railhead during impacting. The study provides a reliable method anduseful datum for the further research on fatigue and wear of railhead and improving the rail jointmode.

关键词： Wheel/rail rail joint Elastic-plastic Contact-impact Finite elementmethod

Frequency/time hopping sequence sets with optimal partial Hamming correlation properties

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Science china(Information Sciences) 2012年第10期55卷 2207-2215页

作者： NIU XianHua 1,2,PENG DaiYuan 1 & ZHOU ZhengChun 3 1 The Provincial Key laboratory of Information Coding and Transmission,Institute of Mobile Communications,Southwest Jiaotong University,chengdu 610031,china 2 The School of Mathematics and Computer Engineering,Xihua University,chengdu 610039,china 3 The College of Maths,Southwest Jiaotong University,chengdu 610031,china 1. The Provincial Key laboratory of Information Coding and Transmission Institute of Mobile Communications Southwest Jiaotong University Chengdu 610031 China 2. The School of Mathematics and Computer Engineering Xihua University Chengdu 610039 China 3. The College of Maths Southwest Jiaotong University Chengdu 610031 China

Frequency hopping/time hopping(FH/TH) sequences have found wide applications in various modern FH/TH spread spectrum communications,such as digital cellular mobile communication,short-range wireless communication,personal communication,and multi-user radar,sonar *** order to evaluate the goodness of FH/TH sequences design,the periodic Hamming correlation function is used as an important ***,the length of correlation window is shorter than the period of the chosen FH/TH sequence,so the study of the partial Hamming correlation of FH/TH sequence is particularly *** this paper,a new class of FH/TH sequence sets with good partial Hamming correlation properties is proposed and *** construction of new FH/TH sequence sets is based upon the generalized m-sequence and generalized Gordon-Mills-Welch sequence over a polynomial residue class *** is shown that new FH/TH sequence sets are optimal with respect to the partial Hamming correlation bound.

关键词： frequency hopping/time hopping(FH/TH) sequence partial Hamming correlation optimal FH/TH sequence set

Analysis of the Effects of Slope Geometry on the Dynamic Response of a Near-field Mountain from the Wenchuan Earthquake

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Journal of Mountain Science 2010年第4期7卷 353-360页

作者： XIAO Shiguo FENG Wenkai ZHANG Jianjing Department of Geoteehnical Engineering Southwest Jiaotong University Chengdu 610031 China State Key laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of Technology Chengdu 610059 China Department of C-eoteehnical Engineering Southwest Jiaotong University Chengdu 610031 China

Fourier spectra and acceleration response spectra of near-field acceleration records of the 2008 Wenchuan Earthquake have been *** fundamental frequencies(or predominant periods) were ***,the natural frequencies of a range of slopes with different geometric characteristics,such as height,slope ratio,and pattern,were *** seismic responses of the slopes were compared,and the variability of seismic response with the above geometric elements was *** show that if slope height increases,and provided that other conditions are unchanged,the natural frequency of the first mode of a doublesurface slope will change as a power ***,natural frequencies will diminish(based on a parabolic function) as the slope angle becomes *** the surface pattern and the number of surfaces on a slope can have a great impact on the seismic response of the ***,within a certain range of slope heights or angles,either height or angle will also greatly influence the variability of the seismic *** results of this research will be helpful to understanding seismic dynamic response features and explaining the ways that slope stability can be affected by earthquakes.

关键词： Wenchuan Earthquake Slope Geometric features Dynamic response Naturalfrequency

Analysis of Earthquake-Triggered Failure Mechanisms of Slopes and Sliding Surfaces

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Journal of Mountain Science 2010年第3期7卷 282-290页

作者： WANG Jian YAO Lingkan Arshad Hussain School of Civil Engineering Southwest Jiaotong University Chengdu 610031 China MOE Key laboratory of High-speed railway Engineering Southwest Jiaotong University Chengdu 610031 China Road and railway Engineering Research Institute Sichuan Key Laboratory of Aseismic Engineering and Technology Chengdu 610031 China national University of Sciences and Technology (NUST) Islamabad 44000 Pakistan

Earthquake-induced landslides along the Dujiangyan-Yingxiu highway after the Ms 8.0 Wenchuan earthquake in 2008 were investigated. It was found that：（1） slopes were shattered and damaged during the earthquake and open tension cracks formed on the tops of the slopes; （2） the upper parts of slopes collapsed and slid, while the lower parts remained basically intact, indicating that the upper parts of slopes would be damaged more heavily than the lower parts during an earthquake. Large-scale shaking table model tests were conducted to study failure behavior of slopes under the Wenchuan seismic wave, which reproduced the process of deformation and failure of slopes. Tension cracks emerged at the top and upper part of model, while the bottom of the model remained intact, consistent with field investigations. Depth of the tension crack at the top of model is 32 cm, i.e., 3.2 m compared to the prototype natural slope with a height of 14 m when the length scale ratio （proto/model） is lo. Acceleration at the top of the slope was almost twice as large as that at the toe when the measured accelerations on shaking table are 4.85 m/s2 and 6.49 m/s2, which means that seismic force at the top of the slope is twice the magnitude of that at the toe. By use of the dynamic-strength-reduction method, numerical simulation was conducted to explore the process and mechanism of formation of the sliding surface, with other quantified information. The earthquake-induced failure surfaces commonly consist of tension cracks and shear zones. Within 5 mfrom the top of the slope, the dynamic sliding surface will be about 1 m shallower than the pseudo-static sliding surface in a horizontal direction when the peak ground acceleration （PGA） is 1 m/s2; the dynamic sliding surface will be about 2 m deeper than the pseudo-static sliding surface in a horizontal direction when the PGA is lo m/sL and the depths of the dynamic sliding surface and the pseudo-static sliding surface will be almost the sam

关键词： Subgrade engineering slope failuremechanism shaking table model test: seismicsliding surface Wenchuan earthquake

SUPER-ELASTIC CONSTITUTIVE MODEL CONSIDERING PLASTICITY AND ITS FINITE ELEMENT IMPLEMENTATION

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Acta Mechanica Solida Sinica 2010年第2期23卷 95-105页

作者： Qianhua Kan Guozheng Kang 1 Linmao Qian(State Key laboratory of Traction Power,Southwest Jiaotong University,chengdu 610031,china) [a] State Key laboratory of Traction Power Southwest Jiaotong University Chengdu 610031 China

Based on the experimental results of super-elastic NiTi alloy, a three-dimensional super-elastic constitutive model including both of stress-induced martensite transformation and plasticity is constructed in a framework of general inelasticity. In the proposed model, transformation hardening, reverse transformation of stress-induced martensite, elastic mismatch between the austenite and martensite phases, and temperature-dependence of transformation stress and elastic modulus of each phase are considered. The plastic yielding of martensite occurred under high stress is addressed by a bilinear isotropic hardening rule. Drucker-Prager-typed transformation surfaces are employed to describe the asymmetric behavior of NiTi alloy in tension and compression. The prediction capability of the proposed model is verified by comparing the simulated results with the correspondent experimental ones. Based on backward Euler＇s integration, a new expression of consistent tangent modulus is derived. The proposed model is then implemented into a finite element package ABAQUS by user-subroutine UMAT. Finally, the validity of such implementation was verified by some numerical samples.

关键词： NiTi alloy super-elasticity plasticity finite element implementation

Analysis on Dam-Breaking Mode of Tangjiashan Barrier Dam in Beichuan County

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Journal of Mountain Science 2011年第2期8卷 354-362页

作者： HU Xiewen LUO Gang LV Xiaoping HUANG Runqiu SHI Yubin Faculty of Geosciences and Environmental Engineering Southwest Jiaotong University Chengdu 610031 China State Key laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of Technology Chengdu 610059 China Aseismic Engineering Technology Key laboratory of Sichuan Province Southwest Jiaotong UniversityChengdu 610031 China chengdu Hydroelectric Investigation and Design Institute China Hydropower Consulting Group Chengdu 610072 China

Tangjiashan landslide is a typical high-speed consequent landslide of medium-steep dip angle. This landslide triggered by earthquake took place in about semi-minute. The relative sliding displacement is 900 meters, so average sliding speed is about 30 meters per second. The longitudinal length of barrier dam which is formed by high-speed landslide along river is 803.4 meters; and maximum width crossing river is 611.8 meters. And its volume is estimated about 20.37 million steres. Through detailed geological investigation of the barrier dam, together with early geological information before earthquake, geological structures of the barrier dam and its stability of upstream and downstream slopes are studied when water level reaches different elevations in condition of continual after shocks with seismic intensity of 7 or 8 Richter scale. On this basis, dam-breaking mode of barrier dam is discussed deeply. Thereby, analytic results provide significant guidance and advices to front headquarters of Tangjiashan barrier dam, so that some proper engineering measures can be implemented and flood discharge can be carried out well.

关键词： Tangjiashan Barrier Dam High-speed landslide Blocking river Dam-breaking

A constitutive model of frozen soil with damage and numerical simulation for the coupled problem

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Science china(Physics,Mechanics & Astronomy) 2010年第4期53卷 699-711页

作者： ZHU ZhiWu, NING JianGuo& MA Wei 1 School of Mechanics and Engineering, Southwest Jiaotong University, chengdu 610031, china 2 State Key laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081, china 3 Key laboratory of Frozen Soil Engineering, CAREERI, CAS, Lanzhou 730000, china 1. School of Mechanics and Engineering Southwest Jiaotong University Chengdu 610031 China2. State Key Laboratory of Explosion Science and Technology Beijing Institute of Technology Beijing 100081 China3. Key Laboratory of Frozen Soil Engineering CAREERI CAS Lanzhou 730000 China

Based on the microcosmic mechanics of composite materials, an elastic constitutive model for frozen soil with damage is presented. For frozen sandy soil with a range of ice contents and under a range of temperature conditions, quantitative results determined by this constitutive model agree with practically measured stress-strain curves. After numerically simulating the coupled water, temperature and stress fields of channel frozen and frozen roadbed using a self-developed finite-element routine, more accurate and practical calculation results for the temperature field coupled with stress, displacement and strain fields are obtained; the results match predictions and tests undertaken by earlier researchers. Our results support the reliability of our routine for calculating interdependent physical quantities of frozen soil and for describing the relationships between them. Our program can offer necessary constraints for engineering design and construction in permafrost regions.

关键词： frozen soil microcosmic mechanics roadbed coupling stress field