西南交通大学学报

Finite Element Analysis of Nonlinear Fracture for Piezoelectric Ceramics

PAN Yi-su, CHEN Da-peng

2000, 13(5): 451-456.

[Abstract](1550)

Abstract:
A nonlinear constitutive model for piezoelectric ceramics is proposed, in which the polarization switching and electric saturation are taken into account. Based on the model, the nonlinear finite element analysis is implemented. Using localJ-integral as a fracture criterion, a relation curve of fracture loads against electric fields is obtained. Qualitatively, the curve is in agreement with the experimental observations reported by Park and Sun.

The Effect of the Non-Metallic Inclusion in 14MnNbq Steel on the Impact Value of Welded Joints at Low Temperature

CHENPeng, JIANG Hai-sheng

2000, 13(5): 457-459.

[Abstract](1080)

Abstract:
The effect of the non-metallic inclusion in 14MnNbq steel on the mechanical properties of welded joints is discussed and analyzed. The result shows that there are a lot of sulfide inclusions (MnS, FeS) in 14MnNbq steel. These non-metallic inclusions badly dispersed in the steel are harmful to the mechanical properties of the welded joint. Their existence will decrease the impact value of the welded joint at low temperature, and increase the discreteness of the measured data.

An Analysis of the Stability of Tracks with Frozen Joints

WANG Ping, LIUXue-yi

2000, 13(5): 460-464.

[Abstract](1387)

Abstract:
A model is proposed for calculating the flexural rigidity of rail joints. The calculation formulas for the stability of the track with frozen joints are deduced. The influences of some parameters, such as joint resistance, installed rail gap and radius of the curve, on the stability of tracks with frozen joints are analyzed and the critical forces in different conditions are listed with a table.

A Fuzzy Optimal Selection Model and Its Application in Multi-Objective Decision Making of Variant Projects in Railway Location

LI Yuan-fu, XUE Bo, DENG Yu-cai

2000, 13(5): 465-470.

[Abstract](1702)

Abstract:
Optimal selection of variant projects in railway location is a process of multi-objective decision making. This paper considers the optimal selection of variant projects in railway location as a process of multi-objective fuzzy optimization, and develops a decision making model of multi-objective fuzzy optimal selection, along with an application software for an engineering project integrated in the model.

Wind Tunnel Test Study on Wind-Induced Internal Force of a Cable-Stayed Bridge Tower

HE Xiang-dong, ZHOU Shu-hua

2000, 13(5): 471-474.

[Abstract](1664)

Abstract:
Based on the static wind force factors of a tower and on the root-mean-square of the buffeting displacement responses of the tower top, which are measured by wind tunnel tests in laminar and turbulent field respectively, the static and buffeting internal forces of the tower bottom control sections under its design wind speed are obtained by linear superposition method and FEM.

Buffeting Analysis for Concrete-Filled Tubular Arch Bridge in Time Domain

LUO Xiong, PAN Yan-yu

2000, 13(5): 475-479.

[Abstract](1581)

Abstract:
The method using the theory of nonstationary random process and a few real wind-velocity records to simulate natural wind is discussed. Then by taking the simulation results as the natural wind in the bridge address, the buffeting analysis in time domain is carried out for an arch bridge of linking pole. A comparison of the calculated results with those obtained by wind tunnel tests shows little difference between them.

Matrix Displacement Method for Concrete Filled Steel Tubular Arch Structures

XIONG Feng, TONG Qiang, LAI Xi-ling

2000, 13(5): 480-483.

[Abstract](1440)

Abstract:
Regarding the concrete filledsteeltube asa compositematerial, thispaperproposesa newmatrix displacement method for analyzing concrete filledsteel tubular archstructures. On the basisof sub-structure analysisof crosssectionsby space finite elementmethod, spacesub-elementsare transformed tobeamelementsofmatrix displacementmethodby plane section hypothesis. Thereby the stiffness matrix of the beam elements is obtained. If further researched, the method can be applied to nonlinear analysis of these arch structures.

Computer Simulation of Corrosive Cracks on RC Members

DAN Dan-hui, WANG Qing-ling

2000, 13(5): 484-487.

[Abstract](1498)

Abstract:
On the basis of the theory of corrosive dynamics for RC and a lot of test data, an expression for the displacement field of the concrete around corroded steel bars is derived. By using the nonlinear finite element method based on the fictitious crack model (FCM) of fracture mechanics of concrete structure, a model is built for analyzing the whole cracking process of the corrosive cracks in RC members. Meanwhile, a computerized simulation for the corrosive cracking process of RC members is carried out with programs made by the authors. Results show that the model proposed in this paper makes it possible to acquire the critical condition for the cracking of corrosive crack and to obtain a quantitative relationship between the corrosive losing rate of steel and the width of corrosive crack.

Sensitivity Analysis of the Influences of Rock Parameters on the Stability of Large-Scale Underground Chambers

YANG Ming-ju, GUAN Bao-shu, WANG Min-shou

2000, 13(5): 488-491.

[Abstract](1451)

Abstract:
In combination with the stability problem of a large-scale underground power station under construction, computation and analysis are carried out for schemes with different combinations of physical parameters of rock (e.g., elastic modulusE, Poisson ratioμ, cohesive forceCand friction angle of the rockφ) by elasto-plastic theory and numerical simulation. The influencing degrees of these rock parameters on the stability of the underground chambers are obtained by employing three dimensional nonlinear finite element method, providing a valuable reference for the survey and design and field construction of underground engineering.

Analysis of Pile Settlement in Layered Soil

HU De-gui, LUO Shu-xue, ZHAO Shan-rui

2000, 13(5): 492-495.

[Abstract](1235)

Abstract:
This paper presents a matrix approach for calculating the pile settlement and shaft-load in layered soil. The soil profile may be arbitrarily layered with a rigid stratum at a certain depth. By contrast with the practically measured data in large-scale cast-in-place pile prototype test, it can be seen that the method proposed in this paper is simple and comparatively accurate in calculating the pile settlement under working load.

Correlation of Scale of Fluctuation with Soil Property Parameters and Its Calculation Method

CHENG Qiang, LUO Shu-xue, PENG Xiong-zhi

2000, 13(5): 496-500.

[Abstract](1512)

Abstract:
The distribution range of the scale of fluctuation is obtained through calculations of hundreds of soil layer’ s CPT data. Then in combination with these calculated results, the calculation methods for the scale of fluctuation and some problems in the calculation are discussed, and the correlation of the scale of fluctuation with other soil property parameters is studied by statistic analysis.

Cause Analysis and Monitoring of Deformation of the Cable Support Tower of Large Span Suspension Bridge During Construction

LIU Cheng-long, ZHANG De-qiang, HUANG Ze-chun

2000, 13(5): 501-504.

[Abstract](1485)

Abstract:
The deformation causes of the cable support tower of large span suspension bridge at different construction stages, as well as the purpose and effect of monitoring the cable support tower deformation, are introduced. A distance difference monitoring method is used to monitor the deformation of cable support tower, obtaining a comparatively good result; and can be taken as a good reference for the same kind of bridge construction.

Organizing of Vector Data in 3D Geographic Information Systems

ZHANG Shan-shan, LIU Wen-xi

2000, 13(5): 505-508.

[Abstract](1328)

Abstract:
The 3D spatial objects related to 3D geographic information systems are defined, and 3D vector data model and structure are put forward to represent the 3D spatial objects. Meanwhile, the topologic relations of the 3D data structures are analyzed and the data structures of the spatial objects are formally described.

Adhesion Analysis of Wheel and Rail with Water Medium

TANWEIgang, TANGHUAIping

2000, 13(5): 509-512.

[Abstract](1314)

Abstract:
Based on the numerical method for the contact of wheel and rail with a water medium, a numerical method of analyzing the adhesive force between high speed wheel and rail with a water medium is developed under the condition of neglecting the part of traction forces transferred by the water medium. For the case that there is a water medium between wheel and rail, the sharp decrease characteristic of the adhesive force between wheel and rail with the increase of the train speed is presented. The mechanism of the decrease characteristic of the adhesive force is qualitatively discussed.

Design of Software for Traction Calculation and Operation Schematic Diagram of Trains

HEHong-yun, ZHUJin-ling

2000, 13(5): 513-516.

[Abstract](1605)

Abstract:
The design goal and method of the software for traction calculation and operation schematic diagram of trains are introduced. Traction experiments and actual using of the software in railway show that the software is convenient to use and the calculated results are accurate, and hence the desired goal has been reached.

Experimental Study on the Running-in Specifications of Diesel Locomotive Engine

SHIXINYu, SHENQUAN

2000, 13(5): 517-521.

[Abstract](1342)

Abstract:
By measuring the topographies of inner surfaces of diesel cylinders, the author carried out a study on the current running-in specifications of Dongfeng 4B diesel locomotive engine through simulation tests. In the tests, after analyzing the state parameters in the running-in process, the author proposed a new test procedure, modified running-in specifications, for the running-in process of cylinders. The new specifications proposed was applied to the running-in test on a practical locomotive diesel engine, and the difference between the topographies of the inner surface of a cylinder was analyzed before and after the running process to estimate the effect of the new procedure. The results show that the running-in time with the new procedure is about 37% shorter than that of the current running-in specifications.

Study on theμRobust Control Design and Its Digital/Analog Hybrid Simulation for Vehicle Active Suspension

HAO Xiao-feng, DAIHuan-yun, XUJun

2000, 13(5): 522-525.

[Abstract](1309)

Abstract:
The robust control law for vehicle active suspension is designed by theμapproach, and the computer control system which realizes the robust control law is simulated using digital/analog hybrid simulation system. Simulation results show that theμcontrol approach satisfies the performance robustness requirement of vehicle active suspension.

A Study on Power Fault Transient Data Compression Based on Optimum Wavelet

HE Zheng-you, QIAN Qing-quan, WANG Xiao-ru

2000, 13(5): 526-530.

[Abstract](1508)

Abstract:
Based on the discussion of the wavelet construction method and the wavelet decomposition theory of multiresolution analysis, in combination with the features of strong instantaneity and quick attenuation of power fault transients, an optimum wavelet construction method based on maximizing the 2-norm of time domain of discrete wavelet decomposition approximation is studied. Computation indicates that this method applied in the compression of power system fault transient data will increase the compression ratio and decrease the reconstruction error.

Improved Transportation Tableau Method for Vehicle Scheduling

LIJun, GUO Qiang

2000, 13(5): 531-534.

[Abstract](1405)

Abstract:
Based on the analysis of characteristics of vehicle scheduling problems, an improved transportation tableau method for preliminary vehicle assignment is designed by Vogel method of transportation tableau, which deals with capacity constraints in the course of vehicle dispatching. The assignment is optimized by optimality test. In the algorithm, the number of vehicles for tasks can be adjusted flexibly. Finally, the algorithm is applied to a practical example, and a discussion on the adaptability and further application of the algorithm is carried out.

A Prediction Model of Demand for Passenger Ticket Booking on Railways

LIUHai-yan, LI Zong-ping, DU Wen

2000, 13(5): 535-538.

[Abstract](1456)

Abstract:
By analyzing the current railway transportation passenger ticket booking system, a prediction model of demand for dynamic multi-seats ticket booking is built. In view of the booking demands of different classes, Poisson distribution is employed to describe the booking arrival rates of different classes in different periods of time. Since the practical railway ticket booking rate is hard to be available, data generated by Monte Carlo simulation are used as numerical examples for estimation of model parameters through MLE approach. Moreover, a model for obtaining the maximum revenue is established by dynamic programming method, and a computation with the practical data shows that the result accords with the actual situation.

Research on Pricing Model of Transport Competition Countermeasure

HE De-quan, GUO Yao-huang

2000, 13(5): 539-542.

[Abstract](1352)

Abstract:
A pricing model of competition countermeasure on price and time in transport is proposed for transport enterprises. Breaking through the pricing model of competition countermeasure against the same transport way only, the model proposed in this paper can be used for making competition countermeasure among different transport ways. At the same time, Logit polynomial assignment model is employed to analyze the pricing countermeasures statically and dynamically, hence helpful to extending the model and to comparing the countermeasure pricing models all round, and supplying a good theoretical basis for directing the pricing of transport enterprises in market economic conditions.

Reliability Evaluation of Sight for Trainman

JINJian, DU Wen

2000, 13(5): 543-545.

[Abstract](1433)

Abstract:
As train raises its speed, the requirement of dynamic vision apperceptive ability for trainman cannot be ignored. The dynamic sights of 158 subjects were measured. Results show that there exist considerable differences in dynamic sights among the trainmen who have similar static sights, that the static sight cannot completely reflect the dynamic vision apperceptive ability, and that both the dynamic and static visions are important indexes for trainmen that cannot be neglected. It is further proposed that the safety threshold value of dynamic vision apperceptive ability is greater than 0.5. At the same time, a system for evaluation and measurement of dynamic apperceptive ability is worked out.

On Model Properties of Lattice Implication Algebra

QIN Ke-yun, XU Yang

2000, 13(5): 546-550.

[Abstract](1184)

Abstract:
Lattice implication algebra is a new algebraic structure to study the lattice valued logic system. This paper is devoted to the study of the model properties of lattice implication algebra. For formalized lattice implication algebra theoryT, it is proved thatTis preserved under submodels, unions of chains and homomorphisms;Tis neither complete nor model complete, and hence there exists no built-in Skolem function. Moreover, the ultraproduct lattice implication algebras and the fuzzy ultraproduct of fuzzy subsets of lattice implication algebras are proposed by using the concept of ultrafilters, with the corresponding properties of fuzzy filters, fuzzy associative filters and fuzzy lattice implication subalgebras being discussed.

Fittinga-NCurve with Four Parameter Equation

SU Yan-jiang, WANG Guang-qin, GAO Qing

2000, 13(5): 551-554.

[Abstract](1345)

Abstract:
When employing the currently widely used three-parameter equation to fit 5 groups ofa-Ntest data of crack propagation, it is found that the fitting precision of the equation for the whole course test data of crack propagation is not high. Especially whenNapproaches the fracture life, the fitting error is getting very large. Therefore, the authors put forward a four-parameter equation, in which the unknown parameters can be obtained by evaluating the extreme value points of poly-function. It is indicated that when fitting the whole coursea-Ntest data of crack propagation, the fitting precision of the four-parameter equation is higher than that of three-parameter equation.

A Free Locking 4-Node Hybrid/ Mixed Plate Element by Tensorial Formulation

WANG Jun, YANG Fan, CHEN Da-peng

2000, 13(5): 555-558.

[Abstract](1011)

Abstract:
A multi-variate functionalПRSis derived from plate functionalПRPby relaxing the constraint between shear strain, rotation and deflection, with shear force introduced as a variate. Then, by tensorial interpolation formulation, the shear strain field can be derived. Making use of the invariance property of tensor, disadvantages due to coordinate transformation are avoided, thus helpful to identify the zero energy modes. By expressing the shear strain in tensorial form, proper selection of optimal shear force interpolating function is successfully achieved on the basis of“one stress parameter per one deformation mode”. Thus, an efficient free shear locking 4-node hybrid/mixed plate element is constructed. Numerical examination reveals remarkable characteristics of Prs against the existing counterparts.

Theory of Generalized Tautology in Lukasiewicz Logic System

WUHong-bo, WANG Guo-jun

2000, 13(5): 559-563.

[Abstract](1210)

Abstract:
Theory of generalized tautology in logic system-W, WandWkis generalized and applied to Lukasiewicz logic system. The main resultsare asfollows: congruence about onset of logic formulasF(S)hasbeenobtained in thesystem; it is proved that in this system, for any irrational numberα, there does not exist accessibleα-tautology; and for any real numberα, there does not exist accessibleα+-tautology; and the relation theorems have been given between categories of generalized contradictions and between categories of generalized tautologies respectively.

A New Kind of Algebraic Systems for Fuzzy Logic

PEI Dao-wu, WANG Guo-jun

2000, 13(5): 564-568.

[Abstract](1193)

Abstract:
Based on a systematic research on fuzzy logic and fuzzy reasoning, a new kind of algebraic systems-R algebras have been established recently, providing a new algebraic basis for fuzzy logic. In this paper, R0algebras are further studied. Some properties of R0algebras are given out, and the relationship among R0algebras and other algebraic systems related to fuzzy logic is clarified.

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2000 Vol. 13, No. 5