bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimal Design of Main Parameters for Pumping Unit of Automotive Power Steering Units
Authors: Li Guang Ming , Cheng Kai , Yan Li
Published: February 2011

We should clean the internal residual hydraulic oil after the automotive power steering units are carried out performance test according to the requirements. In the sake of pumping more residual hydraulic oil efficiently we develop the special pumping unit Based on the orthogonal test, the optimal design of the main parameters pumping unit of automotive power steering units that is the first adding gas time, adding gas interval and adding gas time has been completed in order to determine the optimal program to achieve the best pumping effect.
3D Analysis of Vibration Isolation by Wave Impeding Block in Non-Uniform Layered Ground under Horizontal-Rocking Coupled Loading
Authors: Gao Guang Yun , Zhang Bo , Li Wei
Published: February 2011

The thin-layered method (TLM) is very efficient to the wave propagation in layered ground and boundary element method (BEM) is very precise to solve infinite domain problems. In order to study the isolation vibration effectiveness of non-uniform three-dimensional (3D) layered ground wave impeding block (WIB), this paper is accomplished with the aid of a 3D semi-analytical BEM based on TLM, on which the Green’s function is regarded as fundamental solution of a stratified half-space. Then the active isolation effectiveness by WIB is studied under horizontal-rocking coupled loading in elastic half-space in the upper stiff-layer and lower soft-layer. The results show that the foundation of the stratification parameter and the characteristics of non-uniform have significant influence on the vibration isolation effect of the WIB, and the isolation vibration effectiveness of lower soft-layer is better than the upper stiff-layer.
Study on Thermal Contact Resistance for Heat Transfer of High Power LED Packaging
Authors: Ren Guo Tao , Pan Kai Lin , Zhu Wei Tao , Wang Jiao Pin , Huang Jing
Published: February 2011

Thermal contact resistance is one of key technologies for heat transfer of high power light emitting diodes (LED) packaging. In this paper, based on the resistance network model of LED packaging, a 3-D finite element simulation model (FEM) is established and thermal transient testing experiments are also performed by Thermal Transient tester (T3Ster). Experiment date indicates thermal contact resistance for 48% of the total thermal resistance. The thermal interface material (TIM) layer of high power LED packaging is studied to analysis thermal contact resistance which impacts on thermal performance of LED packaging. The total thermal resistance and the thermal resistance of TIM layer are separately calculated from simulation and experiment. To the resistance of TIM layer, the result of experiment is only a 1% error compared to the result of FEM simulation. Therefore, The FEM simulation and experiment are mutually validated. In order to thoroughly study on thermal contact resistance, based on the principle of structure function, thermal resistance of three different types of TIM layer between metal core printed circuit board (MCPCB) and aluminum heat sink are measured and compared. Experiment results indicate that the quality of interface affects the thermal contact resistance to a great extent.
Modeling for 3-D Temperature Field of Oil-Immersed Transformer
Authors: Qian Su Xiang , Xu Ju Wu , Gu Xiao Jun
Published: February 2011

The knowledge of temperature field of oil-filled transformer directly related to the judgment of overheated fault. There are mainly heat exchange, convection and their coupling in the transformer. Lot of traditional methods are not enough direct-viewing, and ignore the actual situation. The geometrical model of the transformer first modeled by Solidworks, and then ANSYS CFX is used to simulate the temperature field and flow field. Get a set of computer experiment result which can be reference. This computer experiment bring forth the method and effect of the simulate using that software, and make a foundation for the research of transformer overheated fault.
Spreading Resistance Analysis of LED by Structure Function
Authors: Liu Dong Jing , Yang D.G. , You Zhi , Hou Feng Ze
Published: February 2011

In this paper, an investigation on structure function of LED for thermal resistance testing is presented. LED was placed on aluminum plate in different locations. Four group experiments were applied to determine thermal resistance of LED. A simple and effective solution is proposed and discussed on the spreading resistance. The experimental results show the relationship between junction temperature and different locations.
Inaccuracy of Heat Transfer Characteristics for Pin Fins Considering the Influence of Heat Radiation
Authors: Wang Fu Jen , Chang Jung Chieh , Lin Kuo Chien , Wong King Leung
Published: February 2011

Pin fins are widely applied in heat exchanger industry. The heat transfer characteristics of pin fins can be found in many textbooks and handbooks related to heat transfer or heat exchanger. However, most heat transfer experts recognized from their own experiences that the heat radiation effect equation contained the fourth order exponential of temperature and the emissivity of oxidized metal are higher, the inaccuracy of heat transfer rate might be higher while ignoring the effect of heat radiation. In this study, numerical simulation using computational fluid dynamics (CFD) code was conducted to verify the heat transfer characteristics of pin fins. It is found that the error of heat transfer rate generated by ignoring heat radiation will be as high as 45 % while heat convection coefficient is 10 (Wm-2K-1 ) associated with the emissivity of fin surface is 1.0. It also revealed the heat radiation effect cannot be neglected for pin fins, especially for the application under high emissivity and low heat convection coefficient conditions.
Study on Kinematics Simulation of 3-TPT Parallel Machine Tool Based on Pro/E
Authors: Zhao Heng Hua , Wang Chuan Qiang
Published: February 2011

The machinery composition and working principle of 3-TPT parallel machine tool were analyzed. The three dimensional solid models of components of 3-TPT parallel machine tool were designed by using Pro/E. The virtual assembly and connection of the machine tool were accomplished in the assembly environment of Pro/E. Besides, the three-dimensional motion simulation of mechanism about the machine tool was researched in the mechanism module of Pro/E. The three-dimensional animation achieved by the simulation has the strong sense of reality. The working principle of the parallel machine tool was verified by the simulation. The simulation results show that the machine tool has advantages such as good stationarity, no interference and no singularity.
Three Point Suspension Converter's Mechanical System and Elastic Friction Vibration Principle Analysis
Authors: Huang Qing Ming , Xu Jie , Gao Zhan
Published: February 2011

Over the past three decades, three-point support/ suspension converter with brackets would cause abnormal sound and vibration while it tilted over certain angle, and engendered abrasion of bracket contact surfaces, this phenomenon increases mechanical maintenance cost and confuses lots of engineers. Through FEM analysis, three-point suspension converter’s over-constrained mechanical system and elastic friction vibration principle could be revealed, and then the solution proposal was raised. In the engineering practice, the solution proposal has been verified, and some conclusions of those theories have already been proved.
Digital Design of Planetary Gear Mechanism of Thin Seam Shearer Cutting Department
Authors: Jiang Hong Xiang , Du Chang Long , Li Jian Ping , Wu Xin
Published: February 2011

Planetary gear mechanism has compact structure,high single-stage transmission ratio,high loading capacity and efficiency. The volume of planetary gear mechanism influenced coal loading efficiency of thin seam shearer drum.With regard to this, digital product model,digital simulation and simulation were combined to design the planetary gear mechanism of shearer cutting department. It can improve designing efficiency and reliability of planetary gear mechanism，and enhanced coal loading efficiency of shearer drum.
The Dynamic Equations and Response of Hydraulic Excavator’s Working Mechanism System
Authors: Li Zhao Jun , Liu Xiao Su , Yang Xu Juan , Mao Tao
Published: February 2011

By the kinematic and dynamic characteristics analysis of hydraulic excavator’s working mechanism system, the system was divided into three linear varying cross-section beam elements by using Finite-Element Method, then the dynamic differential equation of hydraulic excavator’s working mechanism system was established. The built equation better reflected the intrinsic relationships among the mechanism parameters, load parameters and its nonlinear dynamic properties, and it reflected the dynamic performances which the previous equations didn’t, so it laid the foundation of the further studies of the intrinsic relationships among the dynamics characteristics and mechanism parameters, load parameters of hydraulic excavator’s working mechanism system.
Persist in Cultivation of Engineering Drawing Ability & Improve Ability of Students' Engineering Practice
Authors: Chen Bing , Fan Yu Guang , Wu Chun Yan
Published: February 2011

Currently, the education of engineering college faces the pivotal problem of how to improve students' engineering practice ability. Combining the practice teaching system of engineering practice ability cultivation for the major of process equipment and control engineering in our college, four-year continuous persistent cultivation of engineering drawing ability can improve the students' engineering practice ability effectively and practically.
The Team-individual Approach for Curriculum Design Course in the Mechanical Engineering Education
Authors: He Ping , Chen Nai Chao , Hu Dan Mei
Published: February 2011

The team-individual approach is proposed to act as the teaching method for the curriculum design course in the mechanical engineering education. Firstly, the paper describes the contradictions of the cultivation and requirements for the students between universities and enterprises. Namely, the individual education in the universities is very different with the team spirit with widely recommendations of most modern enterprises. We elucidate the similar feature between team spirit and individual education that is extreme stimulation of the maximum personal intrinsic potential for helping success in their career. Therefore, team-individual teaching method emphasizes on the integration of team-spirit and individual education, by which teacher not only provide the platform for students to arouse their initiative for independent learning and thought but also range their behaviors to enclose the objective of their associated team. In addition, teachers should assess the students based on their work by the oral examination in the limited time and offer the score on the spot and expose it to all the students, which play a vital role on the stimulation for the students. The experimental results in our university show the validation and effectiveness by the team-individual teaching method for the curriculum design course in the mechanical engineering education. Furthermore, team-individual teaching method is also supposed to have the high effective function for the other engineering educations.
Effect of Ultraviolet Irradiation on Photoelectric Properties of Indium Tin Oxide (ITO) Thin Film Deposited by Sol-Gel Method
Authors: Kang Qi , Wu Xu , Liu Jing , Yang Bin
Published: February 2011

Transparent and conductive ITO thin films were prepared on quartz glasses by the sol-gel dip-coating method and treated by ultraviolet irradiation, with 4W (254nm), 15W (254nm), 15W (365nm) and 500W (365nm) respectively. The experimental results suggest that UV irradiation could enlarge the size of crystalline and improve the conductive property of ITO thin films significantly. The relative reduction in sheet resistance rose, resulting from increase in power and irradiating time, as well as decrease in wavelength of UV irradiation. In addition, for those samples which were treated by UV irradiation and placed at room temperature for 20 days, the internal action could cause the conductivity to rise, and decrease the minimum sheet resistance to 41.378Ω/m2.
Research on Energy-Saving Technology in Electric Furnace Dedusting System Based on Information Fusion
Authors: Zhou Bai Qing , Lu Jian Er , Kui Xiu Hui
Published: February 2011

After analyzing merits and demerits of the attempted dedusting methods and the current smelting process, the article presents a new dedusting technique that adopts multi-sensor information fusion. A rational logical control scheme and mathematical model is presented too. The system achieves its environmental protection and energy saving aim by removing dust automatically according to the dynamic dust volume.
Image Identification for Surface Defects of Steel Ball Based on Support Vector Machine
Authors: Yu Yong Wei , Yin Guo Fu , Du Liu Qing
Published: February 2011

In response to the dilemma for image identification by the existing classifier toward surface defects of steel ball, an improved support vector machine (SVM) for multiclass problems is proposed. Minimum distance method is presented to resolve the unclassifiable region of the multiclass SVMs. The 16 image features of the surface defects are selected as input vector of the SVMs. The experiment results show that more accurate identification toward surface defects of steel ball was achieved by the improved multiclass SVM and the accuracy can reach 95%.
Luminescence and Scintillation Properties of Ce-Doped LYSO and YSO Crystals
Authors: Wanarak Chalerm , Chewpraditkul Weerapong , Phunpueok Akapong , Kaewkhao Jakrapong
Published: February 2011

The luminescence and gamma-ray detection properties of the new cerium-doped rare-earth scintillator lutetium-yttrium oxyorthosilicate ( Lu1.95Y0.05SiO5:Ce, LYSO:Ce) were investigated and compared to those of cerium-doped yttrium oxyorthosilicate ( Y2SiO5:Ce, YSO:Ce) crystal. The light yield and energy resolution were measured using photomultiplier tube (PMT) readout. The non-proportionality of the light yield and energy resolution versus γ-ray energy were measured and the intrinsic resolution of the crystals was calculated. In spite of significant progress in light yield and luminescence properties, the energy resolution of LYSO:Ce appears to still suffer from an excess variance in the number of scintillation photons. The mass attenuation coefficient of LYSO:Ce and YSO:Ce for 662 keV gamma rays was also measured by transmission method and compared with the theoretical values calculated by WinXCom program.
High Precision Grinding Wheel Dressing Control Based on PLC
Authors: Ning Zhao , Li Tao , Hui Guo
Published: February 2011

This paper explains PLC control method dealing with grinding wheel dressing, which can be utilized for ultra-precision aviation face gear processing etc. Among the previous processings, shapers and sphericity hob were applied. Whereas gear slotting processing and gear hobbing processing can not achieve project precision. Therefore this new solution was designed: fristly deal with wheel dressing problem, secondly dress face gear with grinding wheel previously dressed. This paper resolved the first problem, within which most crucial part is precise control of switching time. Timers application realized synchronization. There is a PLC managing two driving motors’ synchronization. Two motors working in different but fixed speeds, whilst switching directions at a precisely same time.
A New Technology of Producing Fe-TiC Powder by Mechanical Activation-Reductive Diffusion
Authors: Li Wei , Sun Kang
Published: February 2011

A lower-temperature and cost-efficient way is developed to produce Fe-TiC powders. Fe-TiC is produced by means of mechanical activation -reductive diffusion with ilmenite and graphite. The feasibility of this method and the kinetics of the carbothermic reduction are studied with both natural ilmenite and synthetic ilmenite, respectively. The result approved that Fe-TiC powder could be produced by this new technique; moreover, the particles were prominently diminished in size and activated after ball milling. No obvious reactions were detected when ball milling time was less than 8h by EPMA and XRD; however, the mixed powder of Fe and TiC was obtained after annealing for different time intervals. The kinetic study showed that the apparent activation energy of the reductive reaction decreased gradually with milling time due to mechanical activation, but this effect weakened after ball milling for 6h. As ascertained experimentally, the optimum ball milling time was between 4h and 6h.
A Home-Made Automatic Analyzer to Determine the Dissolved Organic Carbon in Seawater
Authors: Tan Li Ju , Wang Jiang Tao , Li Yue
Published: February 2011

A home-made automatic analyzer to determine the dissolved organic carbon (DOC) in seawater was introduced in this paper. This analyzer was based on ultraviolet-potassium persulphate oxidation method. The analyzer has 7 parts, including sampling, purging of inorganic carbon, enter sample, oxidation, cooling, apart of gas/liquid and analysis of CO2. The program was compiled by programming language of Visual Basic as the control system. All of the action of the analyzer is auto controlled. Different samples are separated by worked air and Milli-Q water and enter the system using six-way valve. With the catalysis of ultraviolet radiation, the organic matter in samples can be oxidated to CO2quantitatively by K2SO2O8and analyzed by non-dispersive infrared (NDIR) detector latter. The results showed that the oxidation efficiency, as well as the detect limit and the veracity are satisfying. The home-made analyzer was compared with the high temperature oxidation method, and the results showed that the two methods have little difference. The cost of the instrument is cheaper, and need not expensive catalyst, so the DOC in seawater can be analyzed with much lower prices.
Microwave Annealing of Cold Compression Deformation Red Copper
Authors: He Wen , Ai Yun Long , Ding Jia Yuan , Liu Li , He Fei
Published: February 2011

Annealing treatment of cold compression deformation red copper was heated by microwave. The feasibility of microwave heating technology applied to heat treatment of metallic materials, and the effect of annealing process on microstructure were discussed. The results show that the phenomenon of arc discharge do not occur during the process of microwave heating red copper, which illustrates that microwave can be used as heat source for heat treatment of metallic materials. When annealing condition is 510°C for 30min, the grains of deformation red copper undergo a transition from fibrous grain to equiaxial grain, and it completes recrystallization. Compared with traditional annealing treatment, microwave annealing treatment can prevent oxidation phenomenon of specimen surface effectively, reduce annealing temperature, shorten heating and holding time, reduce the consumption of energy greatly, and the degree of hardness decline is smaller under the same annealing condition.
Research on Grinding Technology Optimization of Bearing Steel Ball
Authors: Fu Cai An , Zhang Yi Wen , Liu Yuan , Zhang Tao
Published: February 2011

The paper studied on the balling-up mechanism of hard-grinding by focusing on the defects in the process of the hard-grinding of steel ball. In order to achieve better precision and efficiency in the process of producing steel ball, we improves the grinding wheel’s structure by increasing the rotation velocity of the ball and thereby improving the producing efficiency.
Study of the Effect of in-Line Induction Annealing on a Set of Mechanical Properties of TP2 Copper Tube
Authors: Zhao Hong Jin , Peng Li Hong , Mao Cheng , Zhang Zheng Bin
Published: February 2011

Four specifications TP2 copper tubes experienced in-line induction annealing test was studied, mechanical properties of the tubes and the influencing factors were analyzed. The results show that mechanical properties and microstructure of different positions are stable and homogeneous after in-line induction annealing. Mechanical properties of the specimens are not only related to internal factors, but also related to external factors such as environmental temperature.
Cold Extrusion Process Analysis of "Seven-Speed Sleeve" and Forming Parameter Optimization
Authors: Chai Rong Xia , Guo Chen , Hu Hong Qi , Zhang Li Yu
Published: February 2011

The scheme for cold extrusion process of Seven-speed sleeve is determined according to the experiences and analysis by DEFORM-3D software, the extrusion procedure has been numerical simulation analyzed; The part technology and parameters of die structure has been optimized by orthogonal test. The optimized process parameters are as following: friction factor is 0.10, blank height is 31.4mm, extrusion speed is 200mm/s; The optimized parameters of die structure are as following: 1st step convex fillet is 1.5mm, 1st step concave rounded is 2.0mm, 2nd step convex fillet is 2.0mm, 2nd step concave rounded is 1.0mm, 1st step die-entrance angle is 35°, 2nd step die-entrance angle is 60°.The qualified products are obtained using the optimized process parameters in the production practice.
Research on Print-Through and the Prejudging Model Based on the Color Difference Evaluation
Authors: Yang Yong Gang , Gao Qiao Zhuo
Published: February 2011

In order to control the print-through, the value of print-through resistance (PTR for short) was put forward to predict the print-through of lithograph. For 5 given paper samples, the relationships between their PTR and print-through (expressed with ΔEab*) was explored under three sets of printing condition in this paper. The results showed that the PTR increase could lead to decrease of the print-through value. In particular, no matter what kind of conditions, the print-through value was almost smaller than 4NBS when the PTR of those paper samples was larger than 73%, which seems to be the absence of print-through phenomenon.
Effects of Rare Earth on Electrochemical Corrosion Behavior of Graphite-Like Carbon Coatings
Authors: Wang Zuo Ping , Chen Peng Bo , Ma Zhong Wei , Yu Wen Jiang Tao
Published: February 2011

The corrosion behavior of graphite-like carbon (GLC) coating in sea water was studied and yttrium and cerium were doped into it by using mosaic in the target of magnetron sputtering process to improve its corrosion resistance. The result shows that the GLC coating characterizes typical underfilm electrochemical corrosion in sea water. Yttrium added in chromium interlayer or yttrium and cerium added in the surface layer of the GLC coating can apparently improve the microstructure result in significantly decrease the corrosive current density. As the modifications of Y in interlayer and Y, Ce and Ta in top layer are composed together to form complex GLC coating, the wear resistance and the antifriction is dramatically improved, the corrosive current density is only one-twenty fourth of that of the commercial C/Cr GLC coating.
All-Pose Statics Simulation and Strength Calculation of the Excavator Boom
Authors: Ding Qing Xin , Hui Kun Liang , Chen Jian Wen , Chen Juan , Tian Ying Cheng , Yu Jia
Published: February 2011

The boom is one of main load bearing parts for the excavator operation; accordingly, it is very important to make the strength calculation. Considering the excavator boom is of complicated working condition and difficult stress analysis, based on the expression of parts of the excavator working device concerning length parameters of the cylinder, establish the full parameterization model in the MSC.adams, so as to make the secondary development process, automatically achieve the force analysis and calculation of all-poses, and process and save hinged forces under all-poses. In addition to the above, by establishing the finite element parameterization model, invoke the macro command to modify all hinged forces, so as to calculate the max. equivalent stress of the boom under all-poses. The calculation result shows that, the boom can meet the strength requirements under all-poses.
Dynamic Analysis of the Pipe Lifting Mechanism on the Deepwater Pipelaying Vessel
Authors: Yu Kai An , Chen Ke Yu
Published: February 2011

Based on requirements of pipe transport systems on deepwater pipelaying vessel, a new pipe lifting mechanism was designed. It was composed of crank-rocker and rocker-slider mechanism with good lifting capacity and high efficiency. When the slider went to the upper limit position, the mechanism could approximatively dwell, meeting the requirement for transverse conveyor operation. According to the theory of dynamics, numerical analysis method was used to the dynamic analysis of the mechanism. The results showed the maximum counterforce was at the joint between the rocker and ground, and this calculation could be a guideline for the kinematic pair structure designing.
Explore the Dynamic Characteristics of the Off-Road Vehicle Clutch on Release Bearing Life
Authors: Chen Guo Liang , Chen Xiao Yang
Published: February 2011

This article describes the clutch release bearings research on the separation of research methods and characteristics of the bearings described in detail. the off-road vehicle Clutch release bearings often speed, strong vibration, high temperature, humid workability pollution conditions work require release bearings good strength and toughness, resistant to impact wear and excellent contact fatigue performance. Release bearing vibration characteristics and on life affect important theoretical significance and socioeconomic value.
Rheological Properties of Concentrated 1-Allyl-3-Methylimidazolium Chloride Cellulose Solutions
Authors: Lu Fei , Song Jun , Cheng Bo Wen , Zang Hong Jun , Liang Yi
Published: February 2011

The viscosity behaviors and elastic properties of concentrated cellulose 1-allyl-3-methy -limidazolium Chloride solutions were investigated in the concentration from 10 wt% to 25 wt%. Rheological measurement showed that the solution was pesudoplastic fluid. The non-Newtonian behavior was improved and shear-thinning tendency became more pronounced with increasing polymer concentration. The power law index ranged from 0.19 to 0.30. The effects of cellulose concentration to the storage modulus G′ and the loss modulus G″ were analyzed. First normal stress difference (N1) increased with increasing concentration.
Research on Automatic Mechanical Transmission Shift Schedule
Authors: Cao Ya Bin
Published: February 2011

In order to solve some problems existing in the process of shift for automatic mechanical transmission vehicles such as great shift impact, engine noise and low shift success ratio between gears which have large speed ratio differences, a new method used to determine shift schedule was put forward in this paper. In this method, shift schedule and shift quality were synthetically considered, the downshift schedule was obtained based on the same optimization target with upshift schedule and proper downshift delay with shift impact and shift time controlled in a predetermined range. An optimal power shift schedule was developed with this method, and the performance of the automatic mechanical transmission vehicle controlled by this method was compared with that of controlled by skilled driver. The results indicate that the former obviously improved the performance of the vehicle with the shift quality controlled in a predetermined range.
The Design of Worm Wheel Transmission Error Measurement System and the Research on Experimental Method
Authors: Zheng Fang Yan , Chen Zi Ran , Chen Xi Hou , Dong Chun
Published: February 2011

A novel worm wheel transmission error measurement system based on a new space-time subdivision technology is presented in this paper. Non-integer transmission ratio with high precision can be measured with this measurement system. FPGA chip is employed to meet the requirement of high precision and real-time, and USB2.0 meet the requirement of high speed data acquisition and real time data transmission. In addition, precision self-checking is studied with quantitative shifting method, and the experiment method on repeatability test and data processing are studied with dual-observation method. Experiment results prove that this measurement system has high precision and good repeatability.
Crashworthiness Simulation Analysis of Light Sport Aircraft Fuselage Structure
Authors: Chen Pu Woei , Chang Shu Han , Hsieh Yu Yang , Sun Tai Sing
Published: February 2011

In recent years, light sport aircraft, which not only serve the purpose of personal recreation but also act as a means of transportation for medium and short distance travel, have rapidly gained popularity in the general aviation industry worldwide. The FAA established regulations for this new category of airplanes in 2004. However, the crashworthiness requirements for this type of airplane have not been clearly specified. This study used the finite element method to investigate the effect of the impact angle and speed of the LSA fuselage structure on passenger safety during a crash event. We used sink speed defined by NASA AGATE, ASTM and FAR as parameters. The passenger compartment reducing rate defined by MIL-STD-1290A was used for a safety boundary condition. The results show that the maximum cockpit reducing rate of the airplane impact angle is 30o. When the impact angle increases, owing to the engine mount and fire wall’s reinforced structure, this type of airplane can sustain a greater vertical drop speed. When the impact angle is about 80°~90°, the maximum impact speed the fuselage that can be sustained is 33 m/s. This work also completed a simulation of safe and unsafe ranges for light sport aircraft at various impact angles and vertical drop speeds during impact.
State Evaluation for Power Plant Equipment Based on Deviation of Operating Parameters
Authors: Gu Yu Jiong , Zhao Si Yuan , Chen Kun Liang , Yang Kun
Published: February 2011

In view of which the state of equipment cannot be obtained accurately in real-time, a new method of state evaluation is proposed in this paper. Through Fault Tree Analysis (FTA) and Failure Mode Effects and Criticality Analysis (FMECA), the impact of parameters on equipment state is researched and the deviation is defined to quantify the variation of the state of equipment. The evaluating model based on deviation is established and illustrated with an example. The studied case is about the state evaluation for rotor blade and the application proves the method to be effective in the state evaluation for power plant equipment.
Design of Environmental Hardware in Car Alternator Testing System
Authors: Wu Wei Bin , Hong Tian Sheng , Mwape Chileshe Joseph , Li Hao Biao
Published: February 2011

In an automobile, a stable and durable alternator is extremely important. Based on the basic characteristics of the alternators now on the mainstream market, the hardware simulation method was used to build a simulated “car engine-alternator-auto load-the external environment hardware environment” system. High and low temperature humidity test chamber simulates the vehicle internal environment and the inverter driving power frequency conversion is used to simulate motor car engine power system. It uses fixtures, belts, and pulleys to simulate the connection of the engine to the alternator. In addition it uses electronic load cases to simulate automobile electric power consumption with all kinds of current, voltage, speed signal components to provide feedback signals based on the testing system of alternator to make comparisons. The testing system is designed by analyzing and optimizing the structural mechanics of the whole system according to the requirement of the hardware system layout. For each part of the system factors of design were considered included shape, size, material selection process and heat treatment. Parts and detailed drawings were prepared and later sent for fabrication. The tests indicate that hardware alternator testing system has no major defects that can prevent it from being developed for commercial use.
An General Method on Heat Dissipating Capacity in Multidimensional Heat Transfer
Authors: Wang Shi Jie , Xue Ran , Guo Wen Chao
Published: February 2011

Influenced by the geometry and boundary condition’s complexity of the model, as to the heat conductor with complicated shape or non-linear boundary condition, the model must be simplified a lot, before it’s heat dissipating capacity can be calculated with the mathematic method, the course is quite complicated, and the error is large. Utilizing finite element software, an universal program has been worked out by the APDL, and it can output the heat dissipating capacity of appointed surfaces in analysis software. The program is so powerful that it can calculate the heat dissipating capacity of heat conductor in which the heat transfer two-dimensionally or three-dimensionally even if the heat conductor is anisotropic, which is difficult to calculate with the mathematic analysis method. The method mentioned in the paper can diminish the inaccuracy caused by the predigestion with the mathematic analysis method. The calculation principle of the program was introduced in detail. Comparing the result of the program with that got by mathematic method, it was indicated that the calculation error of program is smaller than 1%.
Modern Aerotransport Line Maintance Reliability and Maintainability Index Analysis
Authors: Feng Shi Lin
Published: February 2011

Statistic is used to calculate the reliability and maintainability of the modern aerotransport line maintance. The reliability index and the maintainability index’s chosen process and calculated process in the line maintance is given out in this paper. First the index’s choose process is given out; Second 40 modern aerotransports’ trouble shooting data from November 2007 to December 2008 is given out. According the data, the index’s calculate process is given out; Third the reliability and the maintainability require is given out according the calculate result.
Fuzzy Optimal Design of Tower Crane Jib
Authors: Li Xin Hua , Zhou Jian , Zhang Yi , Dai Ling
Published: February 2011

This article takes the tower crane jib as the optimized object, in view of the jib unique feature, and has established the jib quality optimization objective function, then uses amplification coefficient to obtain its membership function to the fuzzy constraint condition,thus has transformed constraint condition very well. Direct searching tool-box of MATLAB software is adopted to get the optimization model,not only is simplified the optimization process,but also global optimal solution is found reliably.
Design of Magnetic Levitated Thrust Bearing Experiment Table
Authors: Liu Shou Fa , Shi Zhang Jie , Li Chun Feng
Published: February 2011

In this paper, the overall design of magnetic levitated thrust bearing experiment table was completed, of which the main experimental parameters those are electromagnetic parameters and structural dimensions were determined, in addition, the joint debugging and deformation measurement are performed. Analysis results showed that theoretical value, ANSYS simulation results and experimental results were similar, which said that it is feasible to perform stiffness check of the thrust collar on the experiment table.
Oil Droplet Motion Considering Breakup in an Aeroengine Bearing Chamber
Authors: Chen Bo , Chen Guo Ding , Shen Xiao Long
Published: February 2011

Oil droplets can break up during flight and form many secondary droplets in an aero-engine bearing chamber due to aerodynamic drag forces. The motion properties of secondary droplets have significant influence on the two-phase oil/air flow phenomena in bearing chambers. In this work, oil droplet trajectories and velocities are developed by accounting for in-flight breakup. The droplet motion is modelled using a Lagrangian tracking method, and the trajectories and velocities are calculated by numerical integration of the oil particle momentum equation with forth-order Runge-Kutta scheme. The trajectories and velocities change abruptly at the breakup location, compared with unconsidering breakup. Subsequently, the effects of operating conditions on oil droplet motions are discussed. The numerical results show that the influence of breakup on oil droplet trajectory and velocity are considered necessarily when simulating two-phase oil/air flows in bearing chambers.
Contact Angle Model and Wettability of Regular Microsurfaces
Authors: Li Xiao Bing , Liu Ying
Published: February 2011

Wettability of solid surfaces is one of very important properties, which is governed by both the interface energy and the microstructures. In the paper, four microstructure surfaces were designed such as square concave, column concave, square convex and column convex. The contact angle and wettability of solid surfaces with regular microstructures were discussed for five contact angle models such as Young, Wenzel, Cassie, Cassie-Baxter and Wenzel-Cassie models. Then, the impacts of interfacial energy and microstructures to wettability were analyzed. The study shows that the character of hydrophobic or hydrophilic is decided by the interfacial energy between solid and liquid, and the wettability can be changed by adjusting the parameters of microstructures, such as the ratio of transverse spacing and diameter α, the ratio of longitudinal spacing and diameter β, the ratio of the deep and diameter γ or the ratio of soaking deep and diameter λ. And, the convex microstructure is more propitious to hydrohobic surface than concave microstructure.
The Wear Mechanism of DLC Films at Variable Working Conditions
Authors: Chen Chong Liang , Liu Li Guo , Ni Zi Feng
Published: February 2011

The Diamond-like carbon coating (DLC) was derived by the PVCD method on the 45 steel surfaces. The frictional properties and fatigue failure of 45 steel with the DLC films were investigated under three different conditions including full contact condition, horizontal reciprocating movements and vertical reciprocating movements. It was found that (a) at full contact conditions: the increase in the load leads to the initial decrease in the frictional coefficient and then increase, and a lowest frictional coefficient of 0.205 appears at 250N; (b) at horizontal reciprocating conditions: the slow decrease in the frictional coefficient was caused by the increase in load, and frictional coefficients of 0.213 and 0.178 appears at 100N and 300N, respectively; (c) at vertical reciprocating conditions: the frictional coefficient was initially enhanced and then followed by a decrease trend; the highest frictional coefficients of 0.640 appears at load of 200N. The wear rate was slightly enhanced as the load is lower than 200N, and was sharply increased with the further increase in the load. The lowest wear rate was 1.55 mg/10000r, and the highest wear rate was 15.6mg/10000r.
Parameters Identification and Dynamic Analysis of Linear Rolling Guide
Authors: Li Lei , Zhang Jian Run
Published: February 2011

Joint parameters identification is a key problem in the modeling of complex structures. Aimed to solve the joint problem effectively in finite element analysis (FEA), the joint parameters (stiffness and damping) of a linear rolling guide were identified by measuring frequency response functions (FRFs). Hertz contact theory compared with the frequency domain identify method identified the correction of the experiment results. Modal analysis based FEA method coupled with modal test was used to analysis the dynamic characteristics of the linear rolling guide, which confirms that the proposed method can be successfully applied to evaluate the dynamics characteristics of mechanical systems of various configurations.
Analysis of Piston Ring Lubrication with Different Lubricant Supply
Authors: Guo Yi Bin , Lu Xi Qun , Zou De Quan , He Tao , Li Wan You , Li Zi Jun
Published: February 2011

In this paper fully flooded and starved lubrication models considering surface roughness are developed for the piston ring and cylinder bore lubrication. The effect of oil available in the inlet region of a top ring is studied by comparing predicted oil film thickness, asperity contact friction and power loss under different oil supply conditions. The simulation results show that the proper oil supply is important in controlling the piston ring frictional power loss. The influences of lubricant viscosity and composite roughness on frictional power loss of piston ring are also discussed.
Meniscus and Viscous Forces during the Nanoscale Separation of Sphere-on-Sphere Contact Surfaces
Authors: Liu Si Si , Zhang Chao Hui , Zhang Han Bing
Published: February 2011

When two surfaces are brought into contact or at small separations, the liquid between them forms meniscus, which contributes to adhesion and friction. The increased adhesive force and friction are always the substantial cause leading to micro/nanodevices’s failure. In this study, a dynamic contact model of sphere-on-sphere surfaces during nanoscale separation is presented. A numerical analysis of meniscus and viscous forces based on the dynamic contact model has been carried out. During the separation process, the effects of separation distance, initial meniscus height, surface wettability and separating time on meniscus and viscous forces between the contact surfaces are investigated. The results of numerical solution revealed the adhesion mechanism of sphere-on-sphere surfaces during the separation with liquid mediated. The analyses provide a fundamental understanding of the separating process of two sphere surfaces. It is also useful for the design of the de-wetting and antisticking micro/nanoscale surfaces in various devices.
Vibration Characteristic of Shell-Shafting Coupled System Induced by Propeller Exciting Force
Authors: Cao Yi Peng , Li Liao Yuan , Zhang Wen Ping
Published: February 2011

The analysis of underwater structure vibration and noise control has been paid more attention now. The problem about propeller exciting force transfers from shafting, the bearing supporting to structure, causing structure radiated noise is less studied. It is necessary to study the characteristic of coupled system for solving such problem. In this paper, the characteristic of shafting and underwater structure coupled system vibration power flow is analyzed by numerical method and experimental method. The finite element method was adopted to build the analysis model. The force transfer ratio at each bearing supporting are calculated. The transfer function from propeller force to structure response are studied. The vibration characteristics of coupled system are got by numerical method and experimental method. The results show that the coupling vibration effect of shafting and shell are significantly especially at low frequency. The whole coupled system can be excited by propeller force. Some methods should be proposed to reduce this kind of vibration.
Vibration Analysis of Gear Transmission System in Electric Vehicle
Authors: Xie Bi Hui , Zhang Tong , Zuo Shu Guang
Published: February 2011

This paper presents a systematic research on the gear transmission system of the electric vehicle. An accurate 3-D model of the gear transmission system is established in UG (Unigraphics NX) using software Gearwizard, and then imported to ADAMS/View environment. Based on the contact force of ADAMS, the vibration at 3 different test points of the model are simulated. The simulation results seem to be in good accordance with the test results, which proved the validity of the gear transmission model. Finally, the influence of helix angle on vibration at 3 different test points are also researched. The results of the total analysis can be used further to optimize the gear transmission system of the electric vehicle.
Rotor Complex Fault Vibration Analysis Based on Frequency Heterodyne EMD Method
Authors: Hu Hong Ying , Bao Er , Kang Jing
Published: February 2011

Rotor Complex Fault Vibration signals are very hard to analysis since there are many frequencies lies in them. It needs new signal processing methods to deal with these problems. Empirical Mode Decomposition (EMD) is a non-stationary signal processing method developed recently. The frequency heterodyne EMD method can improve the frequency resolution of EMD by shifting the original frequencies to enlarge the frequencies ratio between components. It proves that the method can enhance the performance of EMD easily and effectively. The paper discusses the principle and steps of this method in detail and uses it to analyse rotor complex fault signals. The result shows that frequency heterodyne EMD method can separate different faults and detect the weaker faults in complex fault more effectively than that of normal EMD method.
Analysis of the Influence of Tunnel Blasting to the Neighbor Tunnel
Authors: Wang Hai Liang , Cong Shu Cui , Wang Bi Jun , Liu Lin Sheng
Published: February 2011

According to the tunnel blasting vibration test at Kiaochow bay Cross-harbor Tunnel Guide Line Project, the regulation of the tunnel vibration velocity has been studied. Based on the analytical results, this paper finds that the change regulation of vertical, horizontal radial and tangential vibration velocity as the different distances from the work face. The tunnel vibration velocity of the rear work face is greater than the unexcavated area. The peak value of the rear work face is 2-2.5 times as large as that of the front work face, vibration velocity of the front work face attenuates gently. The paper figures out the relationship between vibration velocity and distance from sensor to the work face, which can offer a reference to similar studies.
Influences Discipline of Tunnel Blasting Vibration on 20 Floors Reinforced Concrete Frame-Shear Wall Structure Building
Authors: Wang Hai Liang , Wang Li , Liu Li Sheng , Wang Bi Jun
Published: February 2011

According to the 20 layers reinforced concrete frame-shear wall structure building, we carried on blasting vibration monitoring in Qingdao Cross-harbor Tunnel Guide Line Project. The monitoring data of vertical vibration velocity and vertical vibration frequency had been analyzed. The results show vertical vibration velocity and vertical vibration frequency had part of intrinsic association. Vertical vibration velocity was enlarged on the top of the building. Vertical vibration frequency was in the range of 101-102 order of magnitude.
Modification of Surface Velocity Calculation Formula in Tunnel Blasting
Authors: Wang Hai Liang , Xue Xian Bin , Li Shao Xian , Li Chuan
Published: February 2011

The blasting vibration in Qingdao Cross-harbor Tunnel Guide Line Project is monitored and analyzed. We discover that the surface particle vibration velocity in the range of 5metres around the working face reduces fast, and that does not conform to Sadaovsk formula. This inquiry adopts the hypothesis-fitting-testing method to modify Sadaovsk formula. The empirical formula of the ground vibration velocity caused by blasting in tunnel is obtained.
Decoupling Free Vibration System of Bridge Section Model
Authors: Zhang Ming Jing , Xin Da Bo
Published: February 2011

In the paper the free vibration system of bridge section model is designed in order to measure the wind-induced effects on the bridge section model in the wind tunnel. In the system the suspension device is constituted with decoupling sliding components and simple spring suspension. Meanwhile, a set of data measurement and acquisition device based on the Labview is provided in the system. The measurement on the wind-induced static force, flutter and vortex-induced vibration of the bridge section model can be conducted at single degree of freedom or multiple degrees of freedom.