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Science china(Technological Sciences) 2010年第2期53卷 512-518页

作者： YANG QiXin, XU Peng & ZHENG ShangFeng 1 School of civil engineering, southwest jiaotong university, chengdu 610031, china 1. School of civil engineering Southwest Jiaotong University Chengdu 610031 China

In this study the computerized tomography (CT) was first used to quantitatively analyze the failure of acrylate spray-applied waterproof membrane in the groundwater environment. The results of the CT tests show that it is feasible to use the CT to quantitatively analyze the failure of the waterproof membrane and the CT method has the advantages of speediness and accuracy that can eliminate the fussy operation process in routine tests. The main conclusions summarized from the study are as follows. First, there are two combined-indexes that can be used to decide the failure of the spray-on waterproof layer: one is that the reduced percentage of the CT number of the spray-on waterproof layer is less than 40.0% and the other is that the variance of the CT number decreases first and then increases. Second, the applicability for the spray-on waterproof layer in the groundwater environment is the SO 24-concentration ≤ 1%, the Cl-concentration ≤ 7.5% and the pH value ≤ 12.0 of the groundwater, respectively.

关键词： spray-on waterproof layer scan CT number failure groundwater environment

Strengths and Fracture Mechanisms of Al_2O_3 Short Fiber Reinforced Al-Mg Alloy Matrix Composite at Elevated Temperatures

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Journal of Materials Science & Technology 2002年第3期18卷 257-260页

作者： Guozheng KANGDepartment of Applied Mechanics and engineering, southwest jiaotong university, chengdu 610031, chinaChuan YANG and Jixi ZHANGDepartment of Materials engineering, southwest jiaotong university, chengdu 610031, china [ Manuscript received Janu SW jiaotong Univ Dept Appl Mech & Engn Chengdu 610031 Peoples R China SW jiaotong Univ Dept Mat Engn Chengdu 610031 Peoples R China

Using the experimental and theoretical methods, the tensile strengths and fracture mechanisms of AI2O3 short fiber reinforced AI-Mg alloy matrix composite at elevated temperatures were researched. The interfacial microstructural characteristics and the fracture surfaces of the composite at different temperatures were observed by transmission electron microscope (TEM) and by scanning electron microscope (SEM), respectively. Then, from the results of microscopic observation, the fracture mechanisms of the composite at different temperatures are discussed. Finally, the tensile strengths of the composite at elevated temperatures were predicted by statistical integration average (SIA) method with the consideration of various fracture mechanisms. It was shown that the strengths and fracture mechanisms of the composite at elevated temperature (300℃) were significantly different from those at room temperature due to the variations of interfacial bonding states. The tensile strengths predicted by the SIA method at elevated temperatures agreed well with the experimental results.

关键词： Fracture A12O3 Al-Mg alloy Composite

Tensile Elastic Modulus, Strength and Fracture of δ-Al_2O_(3f)/Al Alloy Composites

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Journal of Materials Science & Technology 2000年第5期16卷 475-480页

作者： GuoZheng KANG+, Qing GAO and Jixi ZHANG (Department of Applied Mechanics and engineering, southwest jiaotong university, chengdu 610031, china) Department of Applied Mechanics and engineering Southwest Jiaotong University Chengdu 610031 China

Based on the experimental and theoretical analysis, the tensile elastic modulus, strength and fracture characteristics of squeeze casting δ-Al2O3/Al alloy composites were studied. The fracture characteristics of composites were observed by SEM. The elastic modulus was predicted by the finite element method based on the energy equivalence principle, and the strength was predicted by the statistical integration average method using the maximum energy criterion of composite strength. In the prediction, the distribution density functions of the fiber's. orientation and length were considered. These functions were gained by experimental measurement. It is shown that the predicted results are in agreement with the experimental values well and the microstructure feature of composites controls the fracture characteristics.

关键词： Tensile Elastic Modulus Al2O

Self-organized criticality and its application in the slope disasters under gravity

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Science china(Technological Sciences) 2003年第z1期46卷 20-30页

作者： YAO Lingkan, HUANG Yuan & LU Yang School of civil engineering, southwest jiaotong university, chengdu 610031, china southwestern Institute of Physics, chengdu 610031, china SW jiaotong Univ Sch Civil Engn Chengdu 610031 Peoples R China SW Inst Phys Chengdu 610031 Peoples R China

Firstly, three kinds of sand pile experiments which reflect the universal process of energy dissipation within the slope accumulation under the self-organized action are reviewed. They all show that self-organized criticality (SOC) is related to granular non-uniform. The experiment of Tokamak plasma system is introduced, which shows some of SOC properties of Tokamak plasmas in Ohmic region or L-mode. Secondly, material tests in geotechnical engineering and numerical simulations of micro-structure of sand piles indicate that SOC is determined by the structural characteristics. Finally, according to the principle of SOC, the behavior of slope disasters under gravity and its forecast as well as the design of protection engineering are discussed.

关键词： SOC, sand pile experiment, experiment of Tokamak plasma system, slope disasters under gravitation force.

MOTION TYPES AND CHAOS OF MULTI-BODY SYSTEMS VIBRATING WITH IMPACTS

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Acta Mechanica Sinica 1991年第4期7卷 369-375页

作者： Shu Zhongzhou southwest jiaotong university,chengdu 610031,china 1. southwest jiaotong university 610031 Chengdu China

In this paper,the limit sets theory for an autonomous dynamical system is generalized to a multi-body system vibrating with *** discover that if every motion of the system is bounded,it has only four different types:periodic motion 7 t,non-periodic recurrent motion γ2,and non-Poisson stable mo- tions γ3 and γ4 approaching γ1 and γ2, respectively.γ2 is the source of *** is very interesting that cha- otic motions seem stochastic but possess the character of *** way of example,we discuss chaotic motions of a small ball bouncing vertically on a massive vibrating *** result obtained by us is different from that obtained by Holmes.

关键词： multi-body impact vibrations recurrent motion chaos

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

Experimental Study of Tunnel Fire with Natural Ventilation

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湖南大学学报（自然科学版） 2009年第S1期36卷 23-25页

作者： YUAN Zhong-yuan,LEI Bo,CHEN Peng-yun(School of Mechanical engineering,southwest jiaotong university,chengdu,Sichuan 610031,china) School of Mechanical engineering Southwest Jiaotong University Chengdu 610031 China

The 1/15 reduced-scale experiments using Froude scaling were designed to study the effect on the smoke control efficiency for subway tunnel fires with natural ventilation *** propane gas fires with heat release rate 11.48 kW was used,which corresponds to the heat release rate 10 MW in the full-scale *** temperature distributions under the ceiling were measured by K-type thermocouples to investigate smoke movement,and the velocity of smoke in shafts was measured by hot-wire anemometer to obtain the smoke extract amount of ventilation *** results show that the smoke temperature under the ceiling varies with the longitudinal different distance from fire *** results also show that the smoke temperature distributions and the smoke control efficiency in tunnel vary with the space between ventilation shafts and vary with the area and the height of ventilation shaft.

关键词： natural ventilation mode metro tunnel fire reduced-scale experiments froude scaling

Cracking Behaviour of Al_2O_3 Short Fibre/Al-5.5Zn Composite in TEM

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Journal of Materials Science & Technology 1997年第3期13卷 235-237页

作者： Xiyan ZHANG Tianxin TAN Wenyi PENG and Qing GAO (southwest jiaotong university, chengdu 610031, china) southwest jiaotong university Chengdu 610031 China

The micromechanical behaviour of Al2O3 short fibre reinforced Al-5.5Zn matrix composite has been in-situ studied by using TEM. The results show that in the composite the nucleation and propagation of cracks take place mainly in the matrix, as well as in the region near the fibre/matrix interface. It has been also observed that the microcracks can close during *** the fracture property can be characterized by crack open displacement (COD). The cracking characteristic may result from the large strength difference between the matrix and fibre.

关键词： Cracking Behaviour of Al2O3 Short Fibre/Al-5.5Zn Composite in TEM Al Zn

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

Symmetry and horseshoe in the model of bouncing ball

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Chinese Science Bulletin 1999年第4期44卷 315-318页

作者： XIE JianhuaDepartment of Applied Mechanics and engineering, southwest jiaotong Univrsity, chengdu 610031, china Department of Applied Mechanics and engineering Southwest Jiaotong University Chengdu China

By coordinate transformation, the map of bouncing ball has certain symmetry in the new coordinates, This symmetry is used to simplify the conditions which guarantee the existence of the compact, hyperbolic and invariant set and to find the same properties in symbolic dynamics. Based on the analysis, the lower bound of parameter beyond which the map possesses a hyperbolic horseshoe is estimated more precisely.

关键词： bouncing ball symmetry horseshoe symbolic dynamics.