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Liu J.,Central South University | Liu Y.,Zhuzhou Electrical Locomotive Co. | Huang Z.,Central South University | Gui W.,Central South University | Hu H.,University of Essex
International Journal of Modelling, Identification and Control | Year: 2012

This paper focuses on the modelling and control design for an electro-pneumatic braking system used in multi-locomotives in order to achieve accurately and steadily braking control of heavy haul trains. To deal with various time delays, a T-S fuzzy model based on satisfaction degree is proposed to simplify the cylinder model construction and a fuzzy clustering algorithm with forgetting factors is deployed to achieve parameter self-learning in order to improve the fuzzy control accuracy. Then a fuzzy genetic algorithm is adopted as the rolling optimisation method to reduce the effect of coupling noise, system disturbance and communication random interference such that the system robustness and controller response capability are improved. The effectiveness of the proposed method is verified by simulation and practical implementations. Copyright © 2012 Inderscience Enterprises Ltd.


Chen X.,Central South University | Chen X.,Zhuzhou Electrical Locomotive Co. | Chen K.,Central South University | Dong P.,Central South University | And 2 more authors.
Xiyou Jinshu Cailiao Yu Gongcheng/Rare Metal Materials and Engineering | Year: 2013

Based on the heat processing technology of 7085 aluminum alloy aircraft parts, 7085 aluminum alloy in the temperature range of 300~450°C and strain rate range of 0.0001~1 s-1 have been studied by hot compressing testing. Processing map of 7085 aluminum alloy was generated and hot formability was analyzed. The results demonstrate that the temperature range of 340~450°C and strain rate range of 0.0001~1 s-1 is the processing safety area for hot deformation of the 7085 aluminum alloy. The flow instability region occurs in the temperature range from 300°C to 340°C and strain rate range from 0.01 s-1 to 1 s-1. The adiabatic shear bands are generated when 7085 aluminum alloy is deformed in the flow instability region. The structure of adiabatic shear banding is violently elongated grain. The potential processing dangerous area is in the temperature range from 300°C to 340°C and strain rate range from 0.0001 s-1 to 0.01 s-1. The optimal deformation processing parameters are the deformation temperatures ranging from 340°C to 410°C and strain rates ranging from 0.0004 s-1 to 1 s-1. Copyright © 2013, Northwest Institute for Nonferrous Metal Research. Published by Elsevier BV. All rights reserved.


Chen X.-H.,Central South University | Chen X.-H.,Zhuzhou Electrical Locomotive Co. | Chen K.-H.,Central South University | Dong P.-X.,Central South University | And 2 more authors.
Zhongguo Youse Jinshu Xuebao/Chinese Journal of Nonferrous Metals | Year: 2013

The effects of hot working parameters (deformation temperature, strain rate and strain) on the microstructure evolution of 7085 aluminum alloy during compressing were studied systematically by isothermal compressive deformation. The results indicate that both the increase of deformation temperature and the decrease of strain rate are good for dynamic recrystallization, which results in the decrease of the dislocation density of 7085 aluminum alloy and the increase of the recrystallization grains size. With the increase of strain of 7085 aluminum alloy, the dislocation density decreases and the volume fraction of dynamic recrystallization increases. The dynamic recrystallization models of 7085 aluminum alloy, which contain the peak strain equation, critical strain equation, kinetics equation of dynamic recrystallization and grain size equation of dynamic recrystallization, were deduced by the linear regression method.


Fang H.-C.,Central South University | Chen X.-H.,Zhuzhou Electrical Locomotive Co. | Chen K.-H.,Central South University
Fenmo Yejin Cailiao Kexue yu Gongcheng/Materials Science and Engineering of Powder Metallurgy | Year: 2015

Al-Zn-Mg-Cu-Zr, Al-Zn-Mg-Cu-Er-Cr and Al-Zn-Mg-Cu-Zr-Er-Cr alloys were prepared by cast metallurgy. The recrystallization behavior and perperties of Al-Zn-Mg-Cu-Zr, Al-Zn-Mg-Cu-Er-Cr and Al-Zn-Mg-Cr-Zr-Er-Cr alloys were compared by optical microscopy, transmission electron microscopy, tensile test and corrosion resistance measurement. The results show that the dispersed L12-structured Zn, Mg, Cu, Cr-containing Al3(Zr, Er) dispersoids can strongly pin dislocations, stabilize substructures and inhibite the movement of boundaries. A small subgrain structure is maintained even heated at 510 ℃ in Al-Zn-Mg-Cu-Zr-Er-Cr alloy. Hence, the recrystallization temperature of Al-Zn-Mg-Cu-Zr-Er-Cr alloys reaches to 500 ℃. By combined additions of Er and Cr, the critical stress intensity (KISCC) increases from 10.9 MPa/m1/2 to 22.4 MPa/m1/2 and exfoliation corrosion increases from EB+ to EA+, with the improved strength, fracture toughness and ductility. © 2015, Central South University. All right reserved.


Luo Y.,Southwest Jiaotong University | Wu G.,Southwest Jiaotong University | Xia J.,Zhuzhou Electrical Locomotive Co.. | Zhu G.,Southwest Jiaotong University | And 2 more authors.
Gaodianya Jishu/High Voltage Engineering | Year: 2013

Partial discharge (PD) under a sequence of high-repetition-rate square pulses is one of the key factors leading to premature failure of insulation systems of inverter-fed motors. Polyimide (PI) film is an important type of insulating material used in the inverter-fed motors. In this paper, micro-morphology and structure change of PI film aged by bipolar continuous square impulse voltage (BCSIV) with amplitude above partial discharge inception voltage (PDIV) are investigated by scanning electron microscope (SEM). The chemical bonds of PI chain are analyzed through Fourier transform infrared spectroscopy (FTIR). The results show that the degradation mechanism of PI film is the fracturing of chemical bonds caused by the erosion from PDs. Three layers are displayed in both 100 HN film and 100 CR film. The degradation path of PI film is initiated from surface and then gradually extends to the interior with continuous aging. Nano-fillers can retard the degradation of PI film and prolong its lifetime.


Chen L.,Huazhong University of Science and Technology | Zhou L.,Huazhong University of Science and Technology | Tang C.,Huazhong University of Science and Technology | Huang W.,Alcoa | And 7 more authors.
International Journal of Advanced Manufacturing Technology | Year: 2014

This paper describes a study on laser butt welding of 4 and 2 mm SUS301L stainless steel and a detailed analysis of welding joints. The gap tolerance of butt joint was also studied with optimized process parameters. The electrolytic etching in 10 % oxalate solution was used to test the intergranular corrosion of the 4 mm SUS301L welded joint. Fatigue property of the 2 mm SUS301L welded joint was tested under the conditional cycle times of 1∈×∈ 107. Using optical microscopy, the changes of metallurgical microstructure in the weld zone of 4 mm SUS301L were also studied. It has been found that laser butt welding of 4 mm SUS301L is able to achieve sound metallurgical morphology and high strength weld joint when the butt gap is within certain tolerance. The weld joint also has good resistance to intergranular corrosion and has a fatigue limit of 310 MPa. © 2014 Springer-Verlag London.


Zhang S.,Shanghai JiaoTong University | Luo Y.,Shanghai JiaoTong University | Chen B.,Zhuzhou Electrical Locomotive Co.
Hanjie Xuebao/Transactions of the China Welding Institution | Year: 2010

The bogie frame is the most important bearing structure of the locomotive, and its prediction of welding deformation has important significance in ensuring manufacturing accuracy and quality. First, the database of inherent strain for bogie frame structure was established by a lot of computing and practical measure. Then the welding deformation of hexad-axled locomotive bogie frame side-beam was predicted by using software WSDP (welding structure deformation prediction), which is based on the theory of inherent strain and elastic finite element model. The results were totally consistent with experimental data, and the reliability of the database was proved. The study shows WSDP is very useful in welding deformation prediction of large and complex structures.

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