Feng H.-H.,Nanjing Southeast University |
Xu C.-D.,Nanjing Southeast University |
Wan J.,CSR Qishuyan Institute Co.
Mathematical Problems in Engineering | Year: 2014
The water-lubricated bearings have been paid attention for their advantages to reduce the power loss and temperature rise and increase load capacity at high speed. To fully study the complete dynamic coefficients of two water-lubricated, hydrostatic journal bearings used to support a rigid rotor, a four-degree-of-freedom model considering the translational and tilting motion is presented. The effects of tilting ratio, rotary speed, and eccentricity ratio on the static and dynamic performances of the bearings are investigated. The bulk turbulent Reynolds equation is adopted. The finite difference method and a linear perturbation method are used to calculate the zeroth- and first-order pressure fields to obtain the static and dynamic coefficients. The results suggest that when the tilting ratio is smaller than 0.4 or the eccentricity ratio is smaller than 0.1, the static and dynamic characteristics are relatively insensitive to the tilting and eccentricity ratios; however, for larger tilting or eccentricity ratios, the tilting and eccentric effects should be fully considered. Meanwhile, the rotary speed significantly affects the performance of the hydrostatic, water-lubricated bearings. © 2014 Hui-Hui Feng et al.
Zhang N.,Southwest Jiaotong University |
Zhang J.,Southwest Jiaotong University |
Zhang J.,CSR Qishuyan Institute Co. |
Lu L.,Southwest Jiaotong University |
And 3 more authors.
Materials and Design | Year: 2016
Austempered ductile irons (ADIs) with three strength grades and one kind of wheel steel were matched with conventional rail steel and rolling-sliding wear tests were conducted. The results show that the wear rate decreases while the friction coefficient increases with the increase of matrix hardness. The increase of subsurface hardness is due to work-hardening and stain-induced transformation of retained austenite to martensite. The main wear mechanism is delamination and becomes mild with the increase of matrix hardness. ADI austempered at 340. °C shows the reasonable friction and wear behavior as well as relatively superior mechanical properties. © 2015 Elsevier Ltd.
Lei C.,Southwest Jiaotong University |
Lei C.,Zhengzhou Railway Vocational and Technical College |
Xiao S.-N.,Southwest Jiaotong University |
Luo S.-H.,Southwest Jiaotong University |
Zhang Z.-X.,CSR Qishuyan Institute Co.
Tiedao Xuebao/Journal of the China Railway Society | Year: 2013
The state-of-the-art researches of rail vehicles crashworthiness at home and abroad were reviewed. The main methods of train collision researching and the existing problems were discussed. The design and evaluation standards for vehicles of crashworthiness were expounded. The studies show that there exists a big gap between China and abroad in rail vehicle crashworthiness safety technology research, in our country further in-depth research work should be carried out in respect of the relationship between train collision response, and car body structure safety, train collision test standards and test equipment and train derailing mechanism after train collision, and the train crashworthiness standards need to be formulated in line with the actual conditions of our country.
Ma R.-J.,Southwest Jiaotong University |
Yu N.-Y.,Southwest Jiaotong University |
Hu J.-Y.,Southwest Jiaotong University |
Hu J.-Y.,CSR Qishuyan Institute Co.
The Scientific World Journal | Year: 2013
Based on the life cycle cost (LCC) approach, this paper presents an integral mathematical model and particle swarm optimization (PSO) algorithm for the heating system planning (HSP) problem. The proposed mathematical model minimizes the cost of heating system as the objective for a given life cycle time. For the particularity of HSP problem, the general particle swarm optimization algorithm was improved. An actual case study was calculated to check its feasibility in practical use. The results show that the improved particle swarm optimization (IPSO) algorithm can more preferably solve the HSP problem than PSO algorithm. Moreover, the results also present the potential to provide useful information when making decisions in the practical planning process. Therefore, it is believed that if this approach is applied correctly and in combination with other elements, it can become a powerful and effective optimization tool for HSP problem. © 2013 Rong-Jiang Ma et al.
Zhang Z.,Southwest Jiaotong University |
Hu J.,CSR Qishuyan Institute Co. |
Cheng W.,Southwest Jiaotong University
Advances in Intelligent Systems and Computing | Year: 2014
Two-sided assembly lines are widely used in the assembly of largesized products, such as automobiles, buses, or trucks. Two-sided assembly line problem is more difficult than single-sided assembly line problem as the operation directions constrain of tasks and the requirement of parallel work in the task distribution procedure. In this paper, the mathematical model of two-sided assembly line balancing problem type-II (TALBP-II) is given first. And then, an improved ant colony algorithm was constructed to solve TALBP-II. In the algorithm, a hybrid ant-based search rule and a heuristic task distribution rule were used in order to establish a feasible solution, global pheromone trail update, and the optimum solution search strategy are also considered. The feasibility of this algorithm was indicated by a case of a loader final assembly line. © Springer-Verlag Berlin Heidelberg 2014.
Qiu J.-Y.,Changzhou Textile Garment Institute |
Pan A.-X.,CSR Qishuyan Institute Co.
Zhuzao/Foundry | Year: 2014
Microstructure segmentation of ductile iron material was realized by capture and processing with digital image technology. On the basis of the mathematical morphology, the integrated recognition method was put forward, which includes multiple shape factors such as area, aspect ratio and fractal dimension. The segmentation of pearlite and graphite was effectively achieved, which improve the accuracy and efficiency of ductile iron microstructure quantitative metallography analysis.
Qian K.-C.,CSR Qishuyan Institute Co. |
Zhang J.-X.,CSR Qishuyan Institute Co.
Zhuzao/Foundry | Year: 2014
This paper introduces the mechanism of fatigue crack formation, through the experimental analysis and process improvement, the following conclusions were obtained: (1) the non-metallic inclusions composition, quantity, shape, distribution and spatial distribution in matrix and so on influence the properties of steel; (2) the influence of non-metallic inclusions on the strength of the steel is relatively small, but the plasticity, toughness and fracture toughness decrease with the increasing of inclusions; (3) the brake disc friction surface early cracks was caused by non-metallic inclusion quantity to exceed bid, inappropriate morphology and distribution; (4) the deoxidization treatment by using Ca and RE can make non-metallic inclusion spheroidizing, spherical surface area to be the smallest, and will not produce the effect of stress concentration, so as to improve the plasticity, toughness and fracture toughness of steel, to prevent early cracks of brake disc. ©, 2014, Zhuzao/Foundry. All right reserved.
Wan S.,CSR Qishuyan Institute Co. |
Lu D.,CSR Qishuyan Institute Co. |
Ren H.,CSR Qishuyan Institute Co.
Proceedings of the 2011 2nd International Conference on Digital Manufacturing and Automation, ICDMA 2011 | Year: 2011
it introduces the theory of digital radioscopy(DR) &CT testing technology, according to analyze actuaLity of testing for railway key parts and advantage of digital radioscopy(DR) &CT testing technology, and research the feasibiLity for making the technology use in railway rolLing stock key parts, it concludes that the digital radioscopy(DR) &CT testing technology can fit the testing requirements of railway rolLing stock key parts. © 2011 IEEE.
Yao J.-F.,CSR Qishuyan Institute Co.
Zhuzao/Foundry | Year: 2011
The ester-hardened sodium silicate sand technology was adopted to produce qualified, safe and reliable steel castings for localized high-speed electric multiple units (EMU), such as couplers, clamps, etc., which created considerable social and economic benefits. This paper discussed the selection bases of casting technology, raw materials and properties of ester-hardened sodium silicate sand. The application status was presented and the economic benefit was analyzed.
Qiu J.,Changzhou Textile Garment Institute |
Pan A.,CSR Qishuyan Institute Co.
Tezhong Zhuzao Ji Youse Hejin/Special Casting and Nonferrous Alloys | Year: 2014
For the low service life, "flesh out", sticky steel failure in seamless three-roll piercing plug in the early stages, three plug trials with different materials were conducted. By determining rational heating parameters and taking reasonable oxidation programs as well as other measures, the new plug material suitable for the working conditions was presented, and the service life of plug was improved to ensure the quality of the steel and increase production efficiency. ©, 2014, Journal Office of Special Casting and Nonferrous Alloys. All right reserved.