西南交通大学学报

Theoretical Analysis on Flow-Induced Random Responses of Core Barrel of Nuclear Reactors

YANG Yi-ren, LU Li, TANXiao-hui

2001, 14(6): 557-560.

[Abstract](1694)

Abstract:
The random responses of core barrel of a nuclear reactor excited by a fluctuating flow are discussed in this paper. Fluid dynamic forces are divided into two parts, free vibrating fluid dynamics and fluctuating fluid dynamics. By means of finite element method of structure, a theoretic method is dev...

Stability of Pinned-Pinned Beam in a Rectangular Tube Filled with Incompressible Viscous Fluids

LU Li, YANG Yi-ren

2001, 14(6): 561-564.

[Abstract](1441)

Abstract:
The stability of a pinned plate-type beam in a rigid rectangular tube with incompressible viscous fluids flowing within it is studied. The assumption mode method is utilized to derive the motion equations of the structure. The effects of the thickness of the beam and the gaps between the beam and th...

Nonlinear Finite Element Analysis of Hypervelocity Impact

SONG Shun-cheng, TAN Duo-wang

2001, 14(6): 565-561.

[Abstract](1575)

Abstract:
The geometric frame of finite deformation and Bodner-Parton constitutive equations are introduced into the finite element analysis of hypervelocity impact. The physical parameters of materials are determined by comparison of the one-dimensional calculations with the experimental results. From the co...

Impact-Induced Martensitic Transformation and Material Constitutive Equations

DING Gui-bao, SONG Shun-cheng

2001, 14(6): 572-574.

[Abstract](863)

Abstract:
This paper presents the quantitative prediction of the volume fraction of martensitic transformation in a austenitic steel that undergoes a impact loading. The coupling relationship between strain, stress, strain rate, transformation rate and transformed fraction was derived from the OTC model and m...

Mesomechanics Analysis of Fatigue Damages

DAI Zhen-yu, GAO Qinq, CAIJie

2001, 14(6): 575-577.

[Abstract](1573)

Abstract:
Low cycle fatigue tests were carried out on a number of fatigue specimens of 19Mn6 steel. Multiple small cracks initiated on the surface and their propagation were observed by optical metallography. A parameter,DW, is proposed for quantitative description of local fatigue damages based on local dama...

Modeling of Saturated Rachetting Strain for Materials under Uniaxial Cyclic Stress Load

CAI Li-xun, LIU Yu-jie, GAO Qing

2001, 14(6): 578-583.

[Abstract](1280)

Abstract:
Based on a series of uniaxial ratchetting tests of 304 stainless steel, the influences of four stresses (mean, amplitude, peak and valley) on saturated ratchetting (SR) strains are investigated. It is discovered that there exists a unique threshold for peak stress and SR strains vary monotonously wi...

Fatigue Reliability Analysis Model for Structural Members under Random Stress-Time Courses

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

2001, 14(6): 584-587.

[Abstract](1530)

Abstract:
A model for fatigue reliability analysis of structural members under random stress-time courses is proposed. Two kinds of random stresses are taken into consideration. The fatigue reliability of the members under constant amplitude stresses are analyzed based on thep-S-Ncurve of material and the ran...

Elastic-Plastic Analysis of Contact Problems of Wheel/Rail with Surface Micro-Roughness

JIANG Xiao-yu, JINXue-song

2001, 14(6): 588-590.

[Abstract](1404)

Abstract:
The contact element method and original stress method were used to analyze the elastic- plastic contact problem of wheel/rail with measured surface micro-roughness. The distribution of surface contact pressure on the rail was obtained. The results show that the peak value of contact pressure on the ...

Damping Property and Its Micromechanism of ZA27 High Damping Alloy

ZHAO Yu-zhen, GAO Qing, DAI Zhen-yu

2001, 14(6): 591-594.

[Abstract](1260)

Abstract:
ZA27 is zinc alloy which is modified by adding rear earth and Ti, solid-solution and naturally aging. The damping properties of ZA27 and its mechanism are studied. The effect of modification, solid solution and natural aging treatment on damping properties is analyzed. Compare with cast alloy, the d...

Analytical Solution of the Resonance Length for Ultrasonic Torsional Fatigue Samples

WANG Hong, GAO Qing

2001, 14(6): 595-598.

[Abstract](1308)

Abstract:
A method for analytical calculation of the resonance length for ultrasonic torsional fatigue samples is recommended. The angular displacement amplitude and torsional stress/strain amplitude on the surface of samples are derived. Analysis for the stress magnification factor of sample with various cro...

Continuum Theory of Mixture for Freezing and Thawing of Water-Saturated Porous Media

LUHong-lun

2001, 14(6): 599-513.

[Abstract](1262)

Abstract:
With the application of continuum theory of mixture, a mathematical model for the coupled seepage, stress and temperature for freezing and thawing of water-saturated porous media has been established. The conservation equation of water mass, the equilibrium equation of total stress and the conservat...

Coefficient Matrices of Evolution Equation and the Dissipation Effect of Viscoelastic Medium

DAI Guang-ze, XIA Yan, ARAKI Shigetoshi

2001, 14(6): 604-608.

[Abstract](1305)

Abstract:
It is obvious that the exact solutions of the evolution equation, which is derived by regarding the deformation process of viscoelastic materials as an irreversible themodynamic process, depend very much on the properties of their coefficient matrices. These matrices are usually affected by the natu...

Dynamic Stability Analysis of Viscoelastic Cables with Small Sag

LI Ying-hui, GAO Qing, YINXue-gang

2001, 14(6): 609-611.

[Abstract](1613)

Abstract:
Based on the one-dimensional constitutive equation of Relvon materials and the motion equation of cables, the governing equations of the viscoelastic cables in the vertical plane are derived. By using the variable separation method, a linear ordinary equation is obtained, which is expressed by modal...

Study on Wind-Induced Loads of Train-Bridge System by Wind Tunnel Test

GE Yu-mei, LI Yong-le, HE Xiang-dong

2001, 14(6): 612-616.

[Abstract](1750)

Abstract:
The aerodynamic parameters of Wuhu Bridge over the Yangtze River and a high speed running on it were measured respectively by wind tunnel tests. The natural wind loads acting on the train and the bridge were simulated. The calculated wind loads are added into the dynamic equations of train and bridg...

Analysis of Shear Lag Effect of Long-Span Continuous Rigid-Frame Box-Beam Bridges

TANG Huai-ping, TANG Da-pei

2001, 14(6): 617-619.

[Abstract](1353)

Abstract:
The equivalent load resolution method was used in the study. The mechanism of shear lag effect of long-span continuous rigid-frame induced by vertical loads are discussed. The shear flow equilibrium equations of the box-beam are derived by use of three-rod analogous procedure. The shear-lag coeffici...

Optimality Criterion of the Significant Failure Modes of Engineering Structures

LIU Chang-hong, CHEN Qiu

2001, 14(6): 620-623.

[Abstract](1315)

Abstract:
Based on the enumerate significant failure modes on general reliability of structure static strength, using the entropy concept, a relationship between a random-fuzzy parameter and an equivalent random parameter is presented. With the relationship, it can be made good result on the failure models of...

Hopf Bifurcation of Flywheel Governor with Feedback Control Device

DING Wang-cai

2001, 14(6): 624-628.

[Abstract](1493)

Abstract:
The mathematical model of the flywheel governor with a feedback device is proposed. Results show that there existsHopf bifurcation in the system. The bifurcation problem can be solved with a center manifold-normal forms theorem. A controllable condition of the system is presented. It was revealed by...

Chaotic Motions in Nonlinear Vibration Systems

YEJian-jun, CHEN Qiu

2001, 14(6): 629-632.

[Abstract](1469)

Abstract:
In this paper, the chaotic motions of non-linear vibration systems are studied. Some non- linear dynamic equations with second-and third-degree variables are discussed, subharmonic orbits, heteroclinic orbits are obtained, and the conditions for chaos to occur are presented.

Forced Torsional Double-Resonance for a Hydro-Generator under Unsymmetrical Operation

CHEN Gui-qing, YANG Yi-ren

2001, 14(6): 633-636.

[Abstract](1462)

Abstract:
The forced double-frequency resonance of a large hydro-generator unit is studied. The resonance is composed of torsional resonance of whole rotor system and 100 Hz resonance excited by inverted-sequence electricity under short-circle between two phases. By applying energy method, the torsional reson...

Analysis of Dynamic Behavior of an Air Compressor Rotor and Contact Strength of the Keys of the Blades

SHENHuo-ming, TANG Wei

2001, 14(6): 637-640.

[Abstract](1418)

Abstract:
Detailed analysis was conducted on the strength of the gear keys of an air compressor rotor. The distribution of stresses in the key and the pressure stresses on the touching surface was obtained by taking the most unfavorable condition that there is only one key touches the keyslot into considerati...

Vibration Characteristics of a 3-Dimensional Beam-Pier-Pile System

QU Ai-ping, GAO Shu-ying

2001, 14(6): 641-644.

[Abstract](1615)

Abstract:
A mechanical model for a 3-dimensional beam-pier-pile system is proposed with finite element methods for a continuous rigid-frame bridge to analyze its vibration characteristics. The pile-soil system is simplified to build the space model and to calculate the dynamic behaviors of the system. Then th...

Predication of Efficiency of Railway Anti-Noise Barriers with Statistical Energy Analysis Method

WANG Shao-jia, GAO Shu-ying

2001, 14(6): 645-647.

[Abstract](1256)

Abstract:
Statistical energy analysis (SEA) is used to predict the efficiency of railway anti-noise barriers. An analytical model is proposed, which consists of two sub constructions. The result obtained with the proposed model is similar to that with conventional empirical method.

Application of BP Networks in the Stability Analysis of Slopes

ZHANG Ji-ping, CHEN Qiu

2001, 14(6): 648-650.

[Abstract](1554)

Abstract:
A method is introduced to apply the artificial neural networks on the analysis of slopes. The slope stability coefficient is analyzed by considering natural factors and making use of the nonlinear mapping ability of BP networks. Taking the data of the slopes in a loessial area as an example, the cal...

Backstepping Design in Synchronizing Nonlinear Systems

TANXiao-hui, ZHANG Ji-ye, YANG Yi-ren

2001, 14(6): 651-654.

[Abstract](1392)

Abstract:
Backstepping design is a recursive procedure that combines the choice of a Lyapunov function with the design of feedback control. In this paper, a practical backstepping design scheme is proposed for synchronizing nonlinear systems. In the scheme, only one feedback control is required regardless of ...

Research on FEM Metacomputing Environment DPFEM

YUAN Feng, CHEN Qiu

2001, 14(6): 655-658.

[Abstract](1749)

Abstract:
The mutual operation between different network platforms is realized by deliberate combination of Java and CORBA (Common Object Request Broker Architecture), packing the existing FEM software with Java and packing the packed FEM software into distributed calculating components with CORBA. A skeleton...

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2001 Vol. 14, No. 6