Materials Science, Mechanical Engineering and Applied Research

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Authors: Yu Lei Xu
Abstract: Considering the product oil has volume compressibility and volume expansion in different temperature and pressure, calculate the LAN-Zheng- Chang product pipeline in the shutdown during the initial station and 1#valve pressure drop rate, combined with the first station in Lanzhou reservoir area of the oil temperature oil temperature drop analysis is the first station in the main reason of pressure pipeline shutdown early fall, and provides technical support for the other new product oil pipeline.
Authors: Yun Lai Ren, Long Jiang Niu, Feng Hua Cao, Qing Wei Wang
Abstract: Cracks at the boundary of the brittle inclusions inside heavy forgings are major defects detrimental to the forgings’ the fatigue life and impact performance. In the forging process, the stress field around brittle inclusions is the key factor determining whether cracks appear at the boundary. To study the influences of the stress field on the crack initiation, a definition of the Average Stress Intensity (ASI) and its mathematical expression analytic are given. Average Spherical Stress Intensity (ASSI) is used as an index to investigate the rule of the stress field’s influence on the brittle inclusion boundary crack initiation. Numerical simulation results indicate that ASSI is highly relevant to crack initiation at brittle inclusion boundary and it is practical to use it as a parameter to represent the effect of the stress field on the crack initiation at the boundary of the brittle inclusion. As the algebraic value of the ASSI decreases, the crack size decreases. When the algebraic value of the ASSI is less than-2.3, there will have no cracks at the boundary of the brittle inclusion. Hot compression tests at 1220°C are conducted on a Gleeble-3180 thermal mechanical simulator with dedicated specimens and shape anvils. Scanning Electron Microscopy (SEM) is employed to observe the cracks at the boundary of the brittle inclusions inside the specimens. Observed results agree well with the numerical simulation results.
Authors: Ji Ping Lei, Jian Mei Chen
Abstract: To effectively achieve rapid and high-precision measurements of the deformation of steel welded structure, multiple sets of the actual experimental data of steel welded structure are used as the samples, the soft-sensing model of deformation of welded steel structure, which uses the welding current I, the welding voltage U, the welding speed v and the flow of gas qm as arguments, is established by fuzzy least squares support vector machine, and adaptive genetic algorithm is used to optimize the number of positive gasification rules c and the parameters of kernel function σ, training, testing and practical application results show, the optimization of 200 steps, the training relative error which become saturated is 2.43%, the testing relative error is less than 2.45%.
Authors: Fu Liu
Abstract: Because the shell of modern rocket is more and more thin and the body length to diameter ratio increase constantly, influence to trajectory caused by elasticity effect cannot be ignored any more. Based on the model of Euler-Bernoulli beam, the dynamic equations of flexible rocket are derived by using of Hamilton principle. The influence of distributing mass and aerodynamic force and the coupling between longitudinal and transversal vibration are considered. Example shows ballistic range and altitude of rocket are influenced by elastic effects observably.
Authors: Qiang Zhang, Ding Li, Juan Wen, Kai Jia Luo, Zhi Chen
Abstract: Cementing anchor plays an important role in prestressed cementing technology of heavy oil thermal recovery. For there are many problems of other anchor: undrillable structure, not to be satisfied the requirements of continue drilling or deepening old well, the authors have designed a drillable anchor. By the way of using finite element analysis, them obtained that the initial angle 38-40° was the best angle for eating into the formation; verified the intensity of anchor-pin system. Through cycling test, them verified the reliability of the anchor; obtained the curves of flow coefficient and the press differential with different nozzle. The analysis and experimental results is very important in guiding significance to optimize the design of the anchor and prestressed cementing operation.
Authors: Kun Peng Zheng, Yong He Chen, Zhen Biao Wei
Abstract: The impact of plateau environment on working performance of diesel engine is greater, it is important to explore the research of power restoration of diesel engine in plateau environment. In this paper, the numerical simulation model of a whole diesel engine with high-power is established based on the GT-POWER software, and the accuracy of the model is verified by the bench test. Based on this, the best intake air amount of compensation of the engine are calculated with different conditions in plateau environment, the compensation intake device with the idea which the high-pressure air of the vehicle storage is introduced into the engine to restore the power is proposed, and the relevant hardware and software are designed. Through real vehicle tests show that the compensation intake device can improve the dynamic performance of diesel engine effectively, which provide a basis for diesel engine design and improving the applicability of the existing diesel engine of vehicles in plateau environment.
Authors: Xiao Hui Song, Xia Feng, Zhi Zhong Guo, Jun Feng Di
Abstract: This paper presents a new method to locate partial discharge source of transformer single-winding with the transformer single-winding model and Matlab software simulation. This transformer single-winding model is composed of 300m long wire, which is equivalent to the parameter model composed of only capacitors and inductors through the frequency characteristic analysis of transformer winding. In the process of simulation, the bushing and neutral point current of transformer winding are measured when partial discharge occurs in different position. Then we can get position factor related to the current mean and variance measured through calculation, analysis and deduction. Accordingly the position of partial discharge can be found by corresponding relation. This simulation indicates that this method is effective and practical.
Authors: Wen Xia Zhang, Jian Yuan, Zhong Hai Zhou
Abstract: An Underwater part including hardware and software of distributed controller for underwater profile monitoring vehicle is investigated. A finite-time tracking control law based on finite-time trajectory-tracking control method is proposed to make an automation control of the vehicle and a manual/auto swtiched distributed controller on Underwater Profile Monitoring Vehicle is desinged. We give the designing procedure of hardware and software of the controller.
Authors: Guo Lai Yang, Ming Xue Li, Jian Zhong Wang, Da Yu Yin
Abstract: The phenomenon of trapping oil is an inevitable result to ensure oil absorption cavity and oil exhaust cavity are not collude with each other. It directly affects the working performance and service life of the gear pump. This article through analyzing the root cause of it put forward a new way to using an external oil circuit to eliminate it. Adding such an external oil circuit to the gear pump, can make the dead volume linked to oil exhaust cavity when the dead volume is decreasing and make the dead volume linked to oil absorption cavity when the dead volume is increasing. This way eliminates the trapped oil compression and expansion, so as to achieve the purpose of thoroughly eliminate the phenomenon of trapping oil.
Authors: Meng Xiong Zeng, Jin Feng Zhao, Wen Ouyang
Abstract: The control system performance requirement was divided into three parts. They were the stability, rapidity and accuracy. The time-frequency domain analysis in the requirements of three performance were measured through quantitative performance index. The mutual restriction of time-frequency performance and system characteristic parameters of normal second order was discussed. The correlation of system time-frequency performance index was established. The relationship between time-frequency performance indexes in standard two order system was extended to higher order system. The mutually constraining and time-frequency correlation between each performance index was obtained by analysis and calculation. The work had been done above had practical significance to reflect the system dynamic performance in different analytical domains.

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