Chen C.,Yanshan University |
Zhang F.C.,Yanshan University |
Wang F.,Yanshan University |
Liu H.,China Railway Shanhaiguan Bridge Group Co. |
Yu B.D.,China Railway Shanhaiguan Bridge Group Co.
Materials Science and Engineering A | Year: 2017
The microstructures and tensile behaviors of traditional Hadfield steel, named Mn12 steel, and Hadfield steel alloyed with N+Cr, named Mn12CrN steel were studied through optical microscopy, transmission electron microscopy, and scanning electron microscopy, among others. Three different tensile strain rates of 5×10−4, 5×10−3, and 5×10−2 s−1 were selected in the tensile test. The deformation microstructures and fracture morphologies of the two steels after fracture in the tensile test were observed to analyze the tensile deformation response to different tensile strain rates. Results showed that the grain size of Mn12CrN steel was evidently refined after alloying with N+Cr. The grain would not become abnormally coarse even with increasing austenitizing temperature. During tensile deformation, the strength and plasticity of Mn12CrN steel were superior to those of Mn12 steel at the same strain rate. With increasing the strain rate, the changes in strength and plasticity of Mn12CrN steel were less sensitive to tensile strain rate compared with Mn12 steel. The effects of grain refinement and N+Cr alloying on dynamic strain aging and deformation twining behaviors were responsible for this lack of sensitivity to strain rate. © 2016 Elsevier B.V.
Yan D.,Yanshan University |
Yan D.,Virtual Computer |
Yuqian Z.,Yanshan University |
Hongzhu L.,China Railway Shanhaiguan Bridge Group Co. |
Po D.,China Railway Shanhaiguan Bridge Group Co.
Proceedings - 2015 7th International Conference on Measuring Technology and Mechatronics Automation, ICMTMA 2015 | Year: 2015
In order to solve the measurement error, low efficiency and poor consistency problem in traditional contact measuring on the measuring of end surface of turnout rail parts size, a method which was based on machine vision to realize the non-contact type size measurement was provided. Firstly, appropriate industrial CCD and camera lens suitable for the actual situation of the end surface of turnout rail parts black and white image was acquired assisting with the forward illumination light, Secondly, the contour of the end surface in the image was extracted joining with mathematical morphology and dynamic threshold, Lastly, the actual size of rail end was got combined with the result of the camera calibration. The experimental results show the method can obtain the more precise value in the size measurement of the end surface of turnout rail parts. © 2015 IEEE.
Zheng J.,Yanshan University |
Sun H.,China Railway Shanhaiguan Bridge Group Co. |
Jiang C.,Third Railway Survey and Design Institute Group Corporation
2011 International Conference on Multimedia Technology, ICMT 2011 | Year: 2011
Transverse vibrations of bridges stirred by train affect the bridge's safety and comfort of the train. For simply supported beam, the paper deduces the response of the beam under a fixed harmonic load, uniform constant load or uniform moving harmonic load. The conclusion is that the response of the beam under uniform moving harmonic load is only about half of the response under a fixed harmonic load, which makes it reasonable that the train translates into a fixed harmonic load. Then a simplified analysis method of the bridge's vibration is obtained. The Example shows the feasibility of this simplified analysis. © 2011 IEEE.
Han X.-Y.,China Railway Shanhaiguan Bridge Group Co.
Bridge Construction | Year: 2015
To cater for the design requirements of long life of the Hong Kong-Zhuhai-Macao Bridge, the processing technique for the U ribs of the orthotropic steel deck plates and the automatic welding technique for the deck plates of the bridge were studied and the ways of how to improve the fatigue performance of the deck plates through improving the welding quality and welding stability of the U ribs and deck plates were also analyzed. The processing procedures of the U ribs were those of the steel plate leveling → prehandling → steel plate cutting → edge trimming → drilling → groove processing → profiling. The assembling and tack welding of the U ribs were carried out on the special machine tools, of which the tack welding was implemented by the welding robots. The bottleneck that the penetration depth of the U rib welding was difficult to meet the 80% penetration depth as required by the design was thus broken through and the problem that the welding quality was not stable was solved. The application of the flat position fillet welding technique in the processing ensured the appearance, shapes and quality of the welding seams, which made the transition of the welding toes of the welding seams connecting the deck plates and U ribs still smoother and the stress concentration greatly reduced. The fatigue tests made for the fillet welding seams of the U ribs showed that the fatigue performance of the welding seams after application of a series of the new workmanship was greatly improved. ©, 2015, Wuhan Bridge Research Institute. All right reserved.
Ma H.,Dalian Jiaotong University |
Lu G.-Q.,China Railway Shanhaiguan Bridge Group Company |
Zhang J.,Dalian Jiaotong University
Dongbei Daxue Xuebao/Journal of Northeastern University | Year: 2013
The finite element method is applied to solve the wheel-frog contact problem existing in the Datong-Qinhuangdao line. Several wheel-frog contact models with different standard were established, and the standard rail section using the 75 kg/m rail. The elastic-plastic calculation was carried out to analyze the distribution and change laws of the von Mises stress and contact patch. When the wheels pass the frog, the contact paths and ride comfort were also analyzed. The results show that the contact patch of wheel and frog is narrow and long. The von Mises stress is larger than material yield strength and makes the wheel and frog enter the plastic deformation stage, which causes serious wheel-frog abrasion. The von Mises stress at 360~480 mm distance from theoretical nose has larger change. When the wheel with standard profile runs from worn frog wing rail to point rail, the contact patch in point rail is ahead of that in wing rail in the longitudinal direction. It makes the rolling radius difference of different contact point become large and causes serious wheel-frog abrasion. The wheels pass the standard frog smoothly, while the wheel has large vertical displacement when passing worn frog which makes the wheel-frog impact. The research provides a certain theoretical basis for the antifriction measures and design of wheel and frog used in the heavy haul railway.
Wang X.-R.,China Railway Shanhaiguan Bridge Group Co. |
Zhang Y.,University of Sichuan |
Liu Y.,General Research Institute for Nonferrous Metals, China |
Yan J.-T.,The Forth Company of 404 Company Ltd
Yejin Fenxi/Metallurgical Analysis | Year: 2015
The standard sample of microalloy was used as an example to collect the whole-spectrum data by laser-induced breakdown spectroscopy technique. The application of Origin 9.0 software in data processing in plasma emission spectrum analysis (such as the deduction of spectral background, the fitting of spectral profile fitting and multiple overlapping peaks) was introduced detailedly. Al(I) 396.152 nm was used for Lorentz fitting. Some important information including peak area, the peak width at half height and peak height could be obtained by the Lorentz fitting curve. Based on the peak width at half height and the simplified Stark field broadening formula, the electron number density in plasma was estimated, i. e., 2.74×1016 cm-3. In addition, the spectral interference of triple overlapped and undivided peaks of Mn element at 402.8-403.8 nm was corrected by the multiple-peak fitting function. The parameter information such as fitting function was also provided. The quantitative analysis could be conducted according to the peak height and peak area. © 2015, Central Iron and Steel Research Institute. All right reserved.
Xiao Y.,Changsha University of Science and Technology |
Yang C.,Changsha University of Science and Technology |
Yang C.,China Railway Shanhaiguan Bridge Group Co.
Yingyong Lixue Xuebao/Chinese Journal of Applied Mechanics | Year: 2015
The nonlinear dynamic analysis for thin rectangular plate under moving vehicle loads on nonlinear foundation is studied in this paper. Considering the nonlinear foundation, the coupled governing equations for the nonlinear vibration of the thin rectangular plate under moving vehicle loads on nonlinear foundation are established based on the Hamilton principle and the equations are made in dimensionless. The trial functions are constructed to satisfy all the boundary conditions and the governing equations are solved by the Galerkin method and harmonic balance method. The influence of the plate thickness, foundation modulus and moving vehicle loads on the dynamic properties for the coupled system is also discussed. Then the following conclusions are reached: (1) With the coupled system vibration amplitude increase, the frequency tend to increase too; (2) The plate's vibration frequency trends to increase with the increase of its thickness, foundation's reaction modulus, vehicle speed and suspension stiffness when its vibration amplitude is invariant but decrease with the increase of vehicle mass. So it can optimize the coupled system vibration by increasing foundation reaction modulus and it's better to control the vehicle speed and increase its suspension stiffness while considering travelling comfortableness. ©, 2015, Xi'an Jiaotong University. All right reserved.
Sun J.-L.,Yanshan University |
Liu H.-M.,Yanshan University |
Li Y.-Y.,China Railway Shanhaiguan Bridge Group Co. |
Peng Y.,Yanshan University
Kang T'ieh/Iron and Steel | Year: 2015
The horizontal vibration mechanism of hot tandem rolling mill was studied, and the relationship between the horizontal vibration and the rolling process parameters was obtained. Considering the gap between the bearing chock and the housing, the offset of work roll and backup roll, and the nonlinear damping, the nonlinear dynamic model of horizontal vibration of strip rolling mill was established, and the relationship model of horizontal vibration and rolling process parameters was also established. Then, the online horizontal vibration test was carried out on the F2 rolling mill of some steel plant. The test result shows that the horizontal vibration of the work roll is very strong, with an amplitude up to 4.5 g in the middle and later periods and more than 5 g at the end phase, and the main vibration frequencies are 40 Hz and 118 Hz. At the same time, based on the model established, the vibration simulation in the rolling process was made to investigate the effect of strip thickness, rolling speed and tensile stress on horizontal vibration. The simulation results show that: the acceleration amplitude of horizontal vibration is 4.8 g in the simulation, which agrees with the measured results, thus validating the model established. When the strip thickness is thinner, the influence on the horizontal vibration is larger; the influence of rolling speed on the horizontal vibration is strong, and the influence of tension on the horizontal vibration is small compared to other factors. ©, 2014, Chinese Society for Metals. All right reserved.
Liu M.-H.,China Communications Construction Company Ltd. |
Sun P.,China Communications Construction Company Ltd. |
Hu G.-R.,China Railway Shanhaiguan Bridge Group Co. |
Li G.-L.,China Communications Construction Company Ltd.
Bridge Construction | Year: 2016
The Qingzhou Ship Channel Bridge of the Hong Kong-Zhuhai-Macao Bridge is a double-pylon cable-stayed bridge and the pylons of the bridge are the reinforced concrete frame structures. Through careful study of the architectural landscape effect of the bridge, the bracing system connecting the columns of a pylon of the bridge is designed into the "Chinese Knot" style cross bracing of steel structure (hereinafter referred to as the knot style bracing). The shape of the knot style bracing is irregular, the dimensions are large and the design, manufacturing and installation of the bracing are difficult and technically complex. The section of the bracing is the box section of variable depth and with rounded corners. When the bracing is connected with the concrete columns, the combined force transmission way of the "compression bearing-shear transferring" and the connecting boxes are applied. The interior and exterior surfaces of the bracing are protected by the paint coating system and the bracing is also provided with the all-directional maintenance accesses and maintenance facilities. The structural calculation and analysis show that the force conditions of the knot style bracing are safe. The bracing is manufactured and installed in segments. In the manufacturing, special measures have been taken to ensure the global shape of the bracing and in the installation, the pre-embedded segments and bracing segments are installed respectively. © 2016, Wuhan Bridge Research Institute. All right reserved.
Dou Y.,Yanshan University |
Chen M.,Yanshan University |
Zheng Y.,Yanshan University |
Liu H.,China Railway Shanhaiguan Bridge Group Co. |
Dai P.,China Railway Shanhaiguan Bridge Group Co.
Lecture Notes in Electrical Engineering | Year: 2016
To solve the problem of extracting rail end face contour in high quality, this paper proposes a rail end face contour extraction algorithm based on mathematical morphology and adaptive threshold. First, use median filter on the rail end face image captured by the industrial camera, and then design a “※” shaped kernel for image denoising based on mathematical morphology; finally, in contour extraction section, an improved Otsu algorithm combined with a histogram of gradient magnitude automatically determine the threshold. By double threshold detection, extract a complete clear contour of the rail end face. Experimental results show that the algorithm can not only suppress the smaller noise, but also have a good inhibition on noisy blocks. It is a strong self-adaptive algorithm, can get a great rail end face contour. © Springer-Verlag Berlin Heidelberg 2016.