西南交通大学学报

Field Experimental Research on Bearing Capacity of Cast-in-Situ Piles in Xigeda-Rock

WU Xingxu, ZHUANG Weilin, JI Suiwang, XIONG Guobin

2006, 19(6): 669-674.

[Abstract](1700)

Abstract:
To provide a reference for the design of pile foundations of bridges on the Xichang-Panzhihua expressway being constructed,the static loading tests and researches on the axial bearing capacity of 13 cast-in-situ piles set in Xigeda-rock were carried out at Xinjiu in Panzhihua and at Puba in Dechang.Xigeda-rock is an extremely soft rock with the special behaviors of softening,mashing and collapsing due to water,and this kind of rock abounds in a region as long as 90 km along this expressway.The experimental and research results show that Xigeda-rock can be used as the ground of pile foundations,and the construction quality is extremely important to their bearing capacity.

Application of Fractal Cellular Automata to Self-Organized Criticality

SU Fenghuan, YAO Lingkan, GAO Zhaoning

2006, 19(6): 675-679.

[Abstract](1543)

Abstract:
Based on a fractal cellular automata model,the mechanism of self-organized criticality(SOC) of granular mixtures was investigated.The present sandpile experiments with an one-side slope show that the self-organized criticality of granular mixtures is strongly influenced by the non-uniform degree of granular materials.The fractal dimension of grading was calculated using the fractal theory. The results show that there exists a fractal feature in the grading of sandpiles with SOC.So it was supposed that if the fabric characteristics of a system has a fractal nature,a large-dimension non-uniform sandpile,as such a system,presents SOC.A cellular automata model describing non-uniform coefficient and fractal fabric characteristic was built to explain the assumption.Through numerical simulations it was found that a sandpile model takes on SOC when cellular arrangement submits to a fractal distribution to testify the assumption.A discussion about the criterion of SOC shows that the fractal fabric characteristics of a system is the necessary condition for SOC of large-dimension granular mixtures.

Numerical Simulation of Ground Vibration Effects in Shallow Tunneling Blasting

CAO Xiaojun, ZHANG Jichun, LU Helin, GUO Jianqun

2006, 19(6): 680-684.

[Abstract](1807)

Abstract:
By taking a shallow tunnel on the Yuhuai railway as the research object,ground vibration induced by blasting was simulated numerically using a dynamic finite element method.In the established numerical model,the ground and excavating boundaries are regarded as free ones,others as fixed ones,and a measured vibration wave is taken as the import load in numerical calculations.The result shows that the simulated wave of ground vibration is close to the measured wave in shape,and the attenuation laws of vibration velocity with time and distance accords with measured results.A further comparison between the characteristic parameters of simulated and measured waves shows that the simulated wave of ground vibration can reflect the characteristics of particle vibration,and the average values of relative errors of amplitude,main vibration frequency and duration are 9.14%,(12.85%) and 17.57% respectively.

Proper Orthogonal Decomposition-Based Simulation of Spatially Correlated Seismic Ground Motions

HU Liang, LI Li, FAN Jian

2006, 19(6): 685-689,695.

[Abstract](1352)

Abstract:
By combining with the modal truncation technique,the simulation formulas for proper orthogonal decomposition(POD) based on the spectral representation method were derived.Then,a stochastic model for the spatial variation of seismic ground motions was proposed,and the simplified simulation formulas were obtained by the pre-decomposition of the spectral matrixes of seismic ground motions.As a result,only evaluation of eigenvectors of a real spectral matrix rather than a complex one is involved,and high computation efficiency can be obtained for the elimination of the time-consuming Cholesky decomposition procedure and the uses of the fast Fourier transform(FFT) technique and the modal truncation technique.Finally,an application of the formulas to the Longtan river long-span bridge was included as a numerical example to verify this method and illustrate the physical sense of POD.

Updated Lagrangian Co-rotational Formulation for Geometrically Nonlinear FE Analysis of 3-D Beam Element

ZHOU Lingyuan, LI Qiao

2006, 19(6): 690-695.

[Abstract](1773)

Abstract:
To improve the precision and efficiency of computations for a structure with a large displacement and rotation,an updated Lagrangian co-rotational formulation for geometrically nonlinear FE(finite element) analysis of 3-D beam elements was proposed.With this method,a standard updated Lagrangian formulation is adopted to build the equilibrium equations of a beam element,the tangent stiffness matrix is derived from the principle of minimum potential energy,the computational procedure for large rotation is applied to compute new coordinates of elements and nodes,and the rigid displacement is taken away from the total displacement to get strain-producing deformations to obtain the precision increment of internal forces.Finally,two numerical examples were given to testify the correction and precision of this method.

Model and Simulation of Angel of Two-Degree of Freedom for Overhead

ZHANG Zeqiang, CHENG Wenming, ZHONG Bin, TANG Liansheng

2006, 19(6): 696-699.

[Abstract](1653)

Abstract:
To precisely position the load and promptly stop load swing for overhead and gantry cranes,the swing of load and the influencing factors were investigated.A 2-degree of freedom model of load swing angel was derived based on 3-dimensional dynamic equations of the trolley-load system.Dynamic simulation results show that the trolley acceleration has greater effect on the swing angel of load than the rope length,with the swing angle and the angular velocity of swing increasing 0.12 rad and(0.164 rad/s,)respectively,with an increase of 1 times in the acceleration of the trolley;and there is no obvious change in the swing angle and the angular velocity of swing,but the cycle of swing increases 1.3 s,with an increase of 2 m in the rope length.

Finite Element Analysis of Vertical Stiffness of Air Spring System

LIU Zenghua, LI Fu, HUANG Yunhua

2006, 19(6): 700-704.

[Abstract](1765)

Abstract:
The vertical stiffness problem of an air spring system was formulated for finite element analysis,and the nonlinearity of the material,geometry and state,as well as the air-solid coupling,were analyzed theoretically.Finite element model of an air spring system was established with the commercial software ABAQUS,and the rebar element was used for the cords.The vertical stiffness of the air spring system was calculated,and the effects of air pressure and cord angle on it were analyzed.The results show that the vertical stiffness increases with an increase in air pressure,decreases a little with an increase in cord angle.

Goodman-Smith Diagram for Fatigue Reliability Design of Grade B Cast Wheel Steel

CHEN Lei, ZHANG Zimao

2006, 19(6): 705-708.

[Abstract](1882)

Abstract:
To obtain fatigue design data under different reliabilities for grade B cast wheel steel for railway vehicles,a Goodman-Smith diagram of the steel was obtained using probabilistic mechanical properties,fatigue limits,and the data available in S-N curves of the steel covering mid-and-long fatigue lives.The fatigue lives were measured by the running distance of the wheel.The effects of average stresses on fatigue properties were considered in terms of Goodman modification,and the fatigue strength was evaluated with the probabilistic fatigue S-N curves covering the mid-and-short and long lives.The coordinates of octagon vertices of the diagram were determined on an entire probabilistic space.

Surface Morphology and Photoluminescence Properties of ZnO Films Deposited with PLD

LI Jianhua, GOU Zhijian, FAN Ximei

2006, 19(6): 709-712.

[Abstract](1343)

Abstract:
ZnO films were deposited on a Si(111) substrate by laser ablation of a Zn target in oxygen reactive atmosphere.Nd-YAG laser with wavelength of 1 064 nm was used as the laser source.The structure and surface morphology of the deposited ZnO films were characterized with XRD(X ray defraction) and FESEM(field emission scanning electron microscopy),and the optical properties of the films were characterized with photoluminescence.The UV(ultraviolet) and deep level(yellow-green) radiations were observed from the films.The UV radiation is the intrinsic property of ZnO film,and the deep level radiation is due to the existence of oxygen antisite defects(OZn).The intensity of UV and deep level radiations depend strongly on surface morphology and surface roughness of ZnO films.A strongly UV emission is obtainable from ZnO film with surface roughness in nanometer range.

QoS Guaranteed Call Admission Control Strategy for CDMA Networks

FANG Xuming, ZHANG Dandan, ZHU Longjie

2006, 19(6): 713-718.

[Abstract](1606)

Abstract:
To fully meet the requirements of multimedia for CAC(call admission control) mechanisms in CDMA(code division multiple access) systems,a method of calculating the residual capacity was investigated,and a QoS(quality of service) guaranteed dynamic CAC scheme was proposed.The analytical and simulated results show that the proposed CAC scheme may guarantee the QoS of different traffics,and improve the performances of call latency,outage probability and resource utility significantly.

Clustering Method Combining Threshold Algorithm with Ant Colony Algorithm

YANG Yan, ZHANG Zhaotao

2006, 19(6): 719-722,742.

[Abstract](1801)

Abstract:
To improve the quality of clusting analysis,a novel clustering method combining the threshold algorithm with the ant colony algorithm was proposed.With this method,the center and number of clustering are determined by using the clustering algorithm based on threshold,and then the above clustering results are optimized by the K-means algorithm combining with transition probability based on the ant colony algorithm.The experimental results show that the proposed clustering method has a higher F-measure than the K-means and other algorithms.

Mel-Spectral Distortion Measure Based on Perception Model for Objective Speech Quality Assessment

CHEN Huawei, JIN Fan

2006, 19(6): 723-728.

[Abstract](1481)

Abstract:
In order to assess speech quality effectively,a new approach of feature extraction of speech signals,MFSC(Mel-frequency spectral coefficient),was proposed on the basis of the speech perception model.This approach considers both the perceptual nonlinear relation between sound intensity and loudness and the nonlinear perception for frequency in Mel domain.Furthermore,an objective speech quality measure with MFSC feature parameters,referred to as Mel-SD(Mel-spectral distortion measure),was put forward,and speech quality assessment based on Mel-SD for jammed wireless communication systems was given.The experimental results show that the average correlation using Mel-SD is 0.942,increasing by 0.089 and 0.031 respectively compared with Mel-CD(Mel-cepstral distance measure) and PESQ(perceptual evaluation of speech quality).

Cloud Theory-Based Genetic Algorithm

DAI Chaohua, ZHU Yunfang, CHEN Weirong

2006, 19(6): 729-732.

[Abstract](1789)

Abstract:
To overcome the shortcomings of a genetic algorithm(GA).i.e.,low convergence speed and easily getting a local optimum solution,a novel genetic algorithm,cloud theory-based genetic algorithm(CGA),was proposed.CGA is based on both the idea of GA and the properties of randomness and stable tendency of a normal cloud model.In this algorithm,Y-conditional cloud generator is used as the cross operator,and basic cloud generator as the mutation operator.Finally,an experiment of function optimization was carried out and a comparison with standard genetic algorithm(SGA) and adaptive genetic algorithm(AGA) was made to testify the validity of CGA,the proposed genetic algorithm.

Predictive Fuzzy Control Based on Recurrent Neural Network

DU Fuyin, XU Yang

2006, 19(6): 733-736,747.

[Abstract](1701)

Abstract:
Recurrent neural network can forecast future output of plant,based on the function,it can be achieved to predict next sampling period change-of-error.Based on the current error and predictive change-of-error,predictive fuzzy control output of fuzzy logic controller could be obtained by general fuzzy logic control rules,which make control input more fit to system states,improve the control quality.Simultaneity,control model of double systems control in turn were adopted,each system included a FLC and a recurrent neural network,and ensured one system working the other learning at the same time all along,which makes control systems have property of adaptive.The computer simulation results indicate that predictive control improves dynamic quality of system.

Protection of Impedance-Matching Balance Traction Transformer Based on Transformer Model

GUO Lei, GAO Shibin, LI Qunzhan

2006, 19(6): 737-742.

[Abstract](1347)

Abstract:
To identify inrush currents and short-circuit currents caused by internal faults,the transformer protection principle based on the transformer model was used for impedance-matching balance traction transformers(IMBT).By analyzing the electromagnetic characteristics of IMBT,voltage balance equations were derived.As a result,protective actions can be decided by analyzing the difference between the two sides of the voltage balance equations.The action characteristic and action formula for the protection of IMBT were obtained,and the setting principles were put forward by considering errors from current transformer,voltage transformer and protection sets.Finally,a numerical simulation was carried out to show the validity of the action characteristic and protective principles.

Development of DCPD Detection Instrument for High-Voltage Storage Capacitor

ZHANG Xueqin, WU Guangning, QU Yanning, SHU Wen, RAN Hanzheng

2006, 19(6): 743-747.

[Abstract](1434)

Abstract:
Based on the RLC balance resistance detection and Δt(time interval between two consecutive discharges) analysis techniques,a DCPD(direct current partial discharge) detection instrument for high-voltage storage capacitors was developed to estimate the performance of a high-voltage storage capacitor.This instrument consists of a good anti-jamming hardware with a 60 to 250 kHz bandwidth and a DCPD analysis software with signal processing and statistic calculation functions.A DCPD test was carried out on capacitor models respectively with classical inner,contact and overlapping defects.The Δt distribution and discharge spectrum show that the DCPD detection instrument can detect partial discharges and find out the reason of partial discharges and the insulation state of a high-voltage storage capacitor.

Fly-by-Light Point-to-Point Line of Nap-of-the-Earth Flight Control System for Helicopter

MEI Jinsong, YANG Yidong, WANG Xinhua, CHEN Dongmei

2006, 19(6): 748-752.

[Abstract](1289)

Abstract:
In order to achieve the fiber-optical communication with different speeds and data formats,a fly-by-light point-to-point link scheme based on serial communication was proposed.By taking the flight control system of a helicopter as an example,a semi-physical simulation platform was constructed,including communication between the MFCS(explicit model-following control system) computer and the FCS(flight control system) computer and communication between the FCS computer and the actuator.The simulation results show that the center wavelength of LED(lighting emitting diode) of the fly-by-light scheme is 820 nm,the longest transfer distance is 400 m far beyond the practical requisition,and it can track more than 90.11% of the input.

Quantitative Assessment Method for Severity Classification of Air Traffic Control Incidents

YANG Changqi, WEI Guangxing

2006, 19(6): 753-757.

[Abstract](1890)

Abstract:
Severity classification of ATC(air traffic control) incidents was studied with the AHP(analytic hierarchy process) method and by combining the existing assessment methods and the civil aviation rules of China.The factors influencing ATC incidents include vertical separation,horizontal separation,flight path,relative closure rate and intervention of ATC/TCAS.The judgment matrix and the weights of the factors were determined by experts.The maximum point values for the factors and those for the elements in every factor were assigned by referencing the existing assessment methods.The total point values for the factors represent the severity classification,and are classified as high,moderate and low severity.The feasibility and rationality of the proposed method were verified with an example of a real ATC incident.

Product Delivery Plan Based on Making to Order

SHU Liangyou, YAN Qipeng

2006, 19(6): 758-763.

[Abstract](1398)

Abstract:
To respond to customer’s needs and minimize the delivery cost of product under an MTO(make to order) operation environment,customer’s waiting time and delivery costs of product were analyzed,and a non-linear model was derived for minimizing the total costs,including those in product storage,customer’s waiting time and product delivery.The investigation indicates that the optimum vehicle number for product delivery depends on order quantity,operation cost of vehicles,productive efficiency of the manufacturer,storage cost of product and the cost of customer’s waiting time.The delivery plan of product depends only on available vehicles and the optimized number of needed vehicles.A table for selecting product delivery plans was presented,and its usage was illustrated with an example.

Side Payment Mechanism for Design Outsourcing under Incomplete Contract

HAN Jianjun, CHENG Y, GUO Yaohuang

2006, 19(6): 764-768.

[Abstract](1522)

Abstract:
To increase the profit of project owners,a side payment mechanism was proposed for a design outsourcing system composed of one project owner and two design contractors.The influences of the proposed mechanism on the profit of the project owner under an incomplete contract was analyzed using game theory and the principle of information economics.It was found that,the degree of efforts by the winner contractor is positively proportional to the amount of bonus offered by the project owner to the winner contractor,and negtively proportianal to the difference of the evaluation of the design quality by the project owner from the real design quality.However,if a owner uses the side payment mechanism depends on the value of the design and compensation and punishment coefficients.

Pareto Improvement to Return Model in BOT Project

ZHAO Lili, TAN Deqing, HUANG Qing

2006, 19(6): 769-773.

[Abstract](1045)

Abstract:
A traditional return model of the BOT project was derived based on the principle-agent theory.Analysis of the mode indicates that the agent(project company) will not chose an action favorable to the principal(government).This is because the traditional contract does not meet the agent’s participation constraint.A Pareto improvement was made to the traditional return model,which makes the model meet the agent’s participation constraint.In the modified model,the agent will choose an action favorable to the principal,while its own return is not affected.

Design of Flexible Mechanism for Multi-Agent Based on Virtual Enterprises

JIA Diancun, WANG Bo

2006, 19(6): 774-778.

[Abstract](1462)

Abstract:
Introduction of an incentive and constraint mechanism to the contract for a multi-agent based virtual enterprise is a measure to reduce the rigidity in the contract to a certain extent.To reduce the rigidity further,it is necessary to design a flexible mechanism.An incentive and constraint mechanism model and a flexible mechanism model were presented based on dynamic stability.A multi-agent based virtual enterprise could effectively reduce the rigidity using the two models and dynamically adjusting the distribution of profits according to the investment efficiency and contribution of each agent.

Method of Optimal Allocation of Monitoring Efforts for Water Pollution Accident Source

LIU Ying, LIU Dan, YANG Miao

2006, 19(6): 779-782.

[Abstract](1435)

Abstract:
To fully utilize limited monitoring resources,the optimal distribution model was derived by using the optimal search theory to detect the source of suddenly occurred water pollution in a river basin under the condition that the detection function for normal pollution accidents is an exponential function.With this method,an optimal search plan can be obtained to maximize the probability of detecting the source of water pollution within finite time.To testify the validity of the proposed method,a calculational example was given.

Characteristics and Sources of Atmosphere Aerosols in Chengdu Industrial Park

LIU Jing1, ZHANG Jianqiang, ZHANG Yuyu

2006, 19(6): 783-787.

[Abstract](1011)

Abstract:
The phase components,contents of major elements and microelements,surface character-istic and size of atmospheric aerosols in the Chengdu industrial park were investigated by using inductively coupled plasma atom emission spectroscopy (ICP-AES),X-ray diffraction(XRD),Fourier transfer infrared spectroscopy(FT-IR),scanning electron microscope(SEM) and X-ray energy-dispersion spectroscopy(EDX).The research result shows that atmospheric aerosols in the Chengdu industrial park are mainly fine and contain a high content of poisonous and harmful chemical elements,such as Ca,Cu,Zn,As,Pb,Cd and Hg,and main phase components are gypsum,α-quartz,feldspar,kaolinite and non-crystalloid SiO2.The particulate materials in the industrial park originate mainly from soot of burning coal and oil,metallurgical dusts,and road and soil dusts.

Experimental Study on Micronucleus in Root-Tip Cells of Vicia faba Induced by Three Pesticides

TANG Zhengyi, HU Rong, QING Donghong, HUANG Zuoxi

2006, 19(6): 788-792.

[Abstract](1208)

Abstract:
Micronucleus(MCN) test of Vicia faba root-tip was conducted to study the mutation inducing effect of three pesticides: methamidophos(Me),thiophanate-methyl(Th) and moroxydine hydrochloride(Mo) in their normally used concentrations.When each of the three pesticides is used alone,the micronucleus frequencies(MNF) of Vicia faba root-tips of the three test groups are higher than those of the control group(P0.01),showing a dosage effect,and Mo gives more obvious inductive effect than the other two pesticides do.When the three pesticides are used together,the high concentration groups show antagonistic actions,the middle and the low concentration groups show synergistic actions,and different concentrations of the pesticides do not exhibit dosage effects.The optimum concentrations of the pesticides are 0.230 0 to 0.250 0 g·L-1 for Me,0.468 0 to(0.526 0 g·L-1)for Th,and 0.055 6~0.059 2 g·L-1for Mo.

Search Advance Search

Journal Search

Search Type

NewsMore

instruction for authors

Read this journal

LinksMore

2006 Vol. 19, No. 6