Wuhan Railway Bureau
Wuhan Railway Bureau
Liu J.,Wuhan Railway Bureau
Kang T'ieh/Iron and Steel | Year: 2017
The contact fatigue of wheel and rail was studied. Based on the Hertz contact theory and the coulomb law of friction, the calculation model of wheel/rail contact fatigue with rail surface crack was established, and the influence of loading position, axle load, friction coefficient on the crack propagation rate was analyzed, respectively. The results show that, the surface crack of wheel/rail contact includes sliding mode and opening mode, the major damage of crack is the sliding mode, and the most dangerous position for crack leading to fracture is the edge of contact area. The axle load and friction are two important factors affecting the fatigue of rail. As the axle load increases, the KI and KII of stress intensity increase. The KI and KII under the axle load of 20 t increase by 359% and 185%, respectively, compared to that under the axle of 10 t. With the increase of the coefficient friction, the KI and KII increase. The KI and KII under the state of friction coefficient 0.3 increase by 108.7% and 119.3%, respectively, compared to that under no friction. It is clear that the friction force can accelerate the crack growth obviously. Reducing the friction coefficient is an effective method to retard the fatigue of wheel/rail contact, and the solid lubricant should be used firstly when curing the rail. © 2017, CISRI Boyuan Publishing Co., Ltd. All right reserved.
Wang H.,Wuhan University of Technology |
Li X.,Wuhan University of Technology |
Zhao K.,Wuhan Railway Bureau |
Xie B.,Wuhan University of Technology
Zhongguo Jixie Gongcheng/China Mechanical Engineering | Year: 2015
Multilayer metal hot forging die is an effective method to improve the service life of the die based on the idea of FGM. The samples of multi metal hot forging die were prepared through shielded metal arc welding herein. After post weld heat treatment, the microstructure analysis, microhardness test, wear test and impact toughness test were done. The test results show that, interface of cobalt alloy surfacing layer and W6Mo5Cr4V2 surfacing layer bonds in good condition. The microhardness of cross section is in gradient distribution and the surface hardness of cobalt alloy reaches 492HV. Wear resistance is 2.5 times that of H13 and the impact toughness is in a rational range. ©, 2015, China Mechanical Engineering Magazine Office. All right reserved.
Wang X.-Q.,Wuhan University of Technology |
Zou W.-L.,Wuhan University |
Luo Y.-D.,Shenzhen Institute of Investigation and Mapping |
Wang J.-F.,Wuhan Railway Bureau |
Deng W.-D.,Chongqing Communication Institute
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2011
The variation of matrix suction of Gansu loess with temperature is obtained under different compaction degrees and water contents by means of tensiometer, and the soil-water characteristics curves (SWCCs) of Chongqing clay under different compaction degrees are obtained by means of pressure plate apparatus. The test results show that 1 under the same compaction degree and water content, the matrix suction linearly decreases approximately with the increase of temperature; 2 under the same compaction degree and temperature, the matrix suction decreases with the increase of water content; 3 under the same temperature and water content, the compaction degree primarily affects the middle section of SWCCs, and the influence is greater while the compaction degree is higher, but the influence of the compaction degree on the matrix suction is low at the sections of SWCCs with high matrix suction and water content; 4 a linear formula fitting the linear section of SWCCs of Chongqing clay is provided, which includes compaction degree of soil, and it is similar to that for Gansu loess obtained by Professor Chen.
Yin Y.-J.,CAS Institute of Automation |
Wang X.-G.,CAS Institute of Automation |
Xu D.,CAS Institute of Automation |
Zhang Z.-T.,CAS Institute of Automation |
And 2 more authors.
2013 25th Chinese Control and Decision Conference, CCDC 2013 | Year: 2013
When a small object is measured by micro cameras, a sharp image of the whole object is impossible to be obtained because the depth of the object's surface is different and the distance between different parts of the object's surface maybe deeper than the depth of field of the micro camera. The camera is focused on different areas of the object's surface and a series of multi-focus images are taken. The relative depths between the object surface's different sub-regions will be got by comparing image sharpness evaluation function values of multi-focus images' same sub-regions and considering the relative position between the camera and the object. Thus the surface depth is obtained. Multi-focus images' sub-regions with maximum image sharpness evaluation function values are combined into an image. The experimental results verify the effectiveness of the proposed methods. © 2013 IEEE.
Guo F.,Central South University |
Chang-Richards Y.,University of Auckland |
Wilkinson S.,University of Auckland |
Li T.C.,Wuhan Railway Bureau
International Journal of Project Management | Year: 2014
Large infrastructure construction projects are prone to risks. Using desktop review and interviews with stakeholder organizations in two major infrastructure projects (the Yi-wan Railway Construction Project in China and the Northern Gateway Toll Road (NGTR) Project in New Zealand), this study investigated how different project governance structures affect the management of risks. Comparative analysis shows that project governance provides a structured mechanism to identify and address risks as they occur. Despite varied context, two projects relied upon flexible contractual arrangements to leverage risks among project participants. While a centralized, single-agent governance was adopted in the form of Project Management Headquarters (PMH) in Yi-wan Railway project, an alliance governance structure was used in the NGTR project. The former enabled top-down risk allocation whereas the latter encouraged proactive solutions to risk sharing. The research outcomes will inform the decision making among project stakeholders on establishing appropriate project governance arrangements in order to achieve target risk management outcome. By comparing real-time projects of varied scope, complexity and significance, the findings contribute to an improved understanding of the relationship between project organizations and project risk management. © 2013 Elsevier Ltd.
Dong W.,Wuhan Railway Bureau
Wuhan Ligong Daxue Xuebao (Jiaotong Kexue Yu Gongcheng Ban)/Journal of Wuhan University of Technology (Transportation Science and Engineering) | Year: 2011
As research on the action mechanism and the reinforce effectiveness of spray-bolt supporting to wall rock, the model testing and the numerical simulation is used in this paper. The strain inner enclosing rock, displacement of wall, anchorage strain, longitudinal stress are measured and recorded, and the stress feature and the deformation character of spray-bolt supporting in the homogeneous wall rock are researched. And the effect of reinforce effectiveness from selecting of supporting parameter is explored. And then, the reinforce effectiveness of wall rock supported by singly anchorage and spray-bolt supporting analyzed. The calculated result from the finite difference software is similar to the testing data, which could prove the effectiveness and accuracy of parameter selecting and model building. Finally, the reasonable advice on anchorage support parameter and layout scheme is given according to the result.
Hu X.,Wuhan Railway Bureau
Journal of Hohai University | Year: 2014
Two long-period seismic waves with abundant long-period information were selected from earthquake records databases from all over the world. The frequency and spectrum characteristics of these two seismic waves were investigated with the orthogonal HHT (Hilbert-Huang transform) method, and compared with those of two commonly used seismic waves. A complex high-rise building was selected as a case study, in which a finite element model was established with the ANSYS software, and nonlinear dynamic response analysis was conducted on the complex high-rise building with the four seismic waves mentioned above as an input. The results show that the complex high-rise building has different effects in filtering seismic waves, and it can filter long-period seismic waves significantly. In addition, the structure's seismic response to long-period seismic waves is greater than it is to common seismic waves, and the displacement response is more significant than the acceleration responses. ©, 2014, Journal of Hohai University. All right reserved.