bluuebunny/crossref_metadata_2025 huggingface dataset:
Electromagnetic Field Analysis of Hybrid Excitation Vehicle Generator with Low Voltage and High Current
Authors: An Yue Jun , Zhou Li Min , Xue Li Ping , Li Yong
Published: November 2012

In order to further improve the power supply system reliability of low voltage high current vehicle generator, hybrid excitation is used and the permanent magnets are added between the main magnetic poles body and pole shoes. Aiming at reply the problem of limited installation space, the asymmetric pole structure, non-uniform commutating pole, single wave windings playing a role of the pressure line and oblique brush etc are investigated for improving commutation. This paper researched on the distribution of the flux line, the waveform of the air gap magnetic field, and analysis inner magnetic field at the loading by hybrid excitation and no loading by permanent magnet excitation alone respectively with the method of finite element. The results reveal that the magnetic field established by several excitation systems is still symmetric and uniform although the asymmetric structure, so it ensures the provision of suitable medium space for mechanical and electrical energy conversion. By comparing the permanent magnets excitation alone and hybrid excitation in a generator magnetic field distribution and air gap magnetic field waveform, the permanent magnet excitation and electricity excitation realized the superposition of magnetic field, and common establish main generator magnetic field. Hybrid excitation also reduces the current density of excitation coils and improves the heat dissipating performance compared with electrically excited alone. Through the performance analysis of the hybrid excitation, the output voltage waveform is very stable. The curve of auxiliary excitation current along with velocity variation provide important basis for excitation control devices and the development of control algorithm. It will help to improve the stability, reliability and security of the generator, the results can provide key technical support to the development of low-voltage high-current hybrid excitation vehicle generator.
Voltage Waveform Control of Three-Phase PWM Inverter Based on the Output Harmonic Current Feed-Forward Compensation
Authors: Tao Wang , Soomro Amir M. , Liao Xiao Zhong
Published: November 2012

A control scheme based on the load harmonic current feed-forward compensation for three-phase pulse width modulated (PWM) voltage source inverter is presented. This control scheme is designed to improve the quality of the three-phase inverter output voltage under nonlinear load. The model of the control system in the d-q coordinate system is established based on the traditional double loop control where the feed-forward current is taken from a band pass filter. In order to analyze this compensation method, the system is divided in to two subsystems and each subsystem is analyzed, and the structure of the output harmonic current feed-forward compensation channel is given. Simulation and experimental result validate that the proposed feed-forward compensation method has a good steady state performance and dynamic responses.
Laguerre Function’s Based Model Predictive Control of Three Phase Induction Motor
Authors: Asad Bilal , Hasan K.M.
Published: November 2012

Electrical drives play a vital role in industrial and domestic applications, so these drives must be more efficient and easy to control. Conventional control methods are well established and nearly fulfill all demands of modern electrical drives but there is still a need to improve these controllers. In this paper it is proposed that the conventional field oriented controllers can be replaced by Model Predictive Controllers (MPC) which are currently being used as process controllers. These MPC controllers are preferred over conventional field oriented controllers because they can predict future behavior of system and according to that predicted value they can adjust their present input in order to minimize the error signal. The major drawback of conventional MPC is that a lot of mathematical iterations are required to predict the future behavior of system so Laguerre function’s based MPC model is used to reduce the mathematical effort and results are validated for a three phase induction motor.
Electronic Control Unit Design for a Retrofit Fuel Injection System of a 4-Stroke 1-Cylinder Small Engine
Authors: Muslim Mohd Taufiq , Selamat Hazlina , Alimin Ahmad Jais , Hushim Mohd Faisal
Published: November 2012

Most motorcycles in developing countries use carburetor systems as the fuel delivery method especially for models with the cubic capacity of less than 125cc. However, small gasoline fuelled engines operating using carburetor system suffer from low operating efficiency, waste of fuel and produce higher level of hazardous emissions to the environment. In this study, an electronic control unit (ECU) is designed and simulated for a retrofit fuel injection (FIS) system. The ECU is targeted to have a simple design, reliable and offers all of the necessary functions of the modern ECU. The simulation results shows that the designed ECU can determine the injection period as close to the proposed value and can drive the injector efficiently based on the generated PWM pulse.
The Study on 20W/40 Heavy Duty and Super-Charged Diesel Oil
Authors: Zhang Jia Xi , Zhao Yan Hui
Published: November 2012

Based on a lot of tests, domestic based oil and additives were chosen according to the working characteristics of heavy duty and supercharged diesel in this paper. The nyctinasty of compound additive produced by American EXXON company and domestic CD-package to based oil was inspected respectively by tests[1]. Dealing with the datum of orthogonal test by computer, the three optimum formulates of 20w/40 heavy duty and supercharged diesel oil were presented.
Thermophysical Properties of Nanoparticles-Phase Change Material Compositions for Thermal Energy Storage
Authors: Lin Saw Chun , Al-Kayiem Hussain Hamoud
Published: November 2012

Utilizing the Phase change material or PCM as thermal storage in solar research has been widely focused. Some researches embedded metal and non-metal Nanoparticles into the PCM to investigate the effect on the thermal properties of the mixtures. In this study, copper nanoparticles are dispersed into paraffin wax to form Nanoparticles-PCM mixture. Three samples have been prepared: Sample 1 is paraffin wax only, Sample 2 is 1% 20nm copper powder + 150 ml paraffin wax, and Sample 3 is 2% 20nm copper powder + 150 ml paraffin wax. Differential Scanning Calorimeter is used to analyse the melting point, solidification point and specific heat of mixture. Transmission Electron Microscopy is used to identify the shape and size of 20nm copper powder. The study showed that thermal conductivity of Nanoparticles-PCM mixture was increased as well as the sensible heat. However, there is reduction in the melting point and heat flow to melt the Nanomaterials but latent heat of fusion was increased. 20nm copper powder is proven to be suspended in the paraffin wax.
A Novel Design in Micro-Air-Vehicle: Flapping Rotary Wings
Authors: Wu Jiang Hao , Zhou Chao , Zhang Yan Lai
Published: November 2012

A novel design in micro-air-vehicle using flapping rotary wings with different wing spanwise length and area is proposed. With the wings flapping, produced thrust makes the wings rotation. Furthermore, lift force from rotary wings increases and overcomes the MAV weight. On the basis of this principle, a mechanical model is made and sample experiments of averaged lift measurement in different wing length and area and angle of attack are executed. It is shown that the maximum averaged lift produced by micro flapping rotary wings can reach to 80mN approximately close to the weight of MAV.
Friction Stir Spot Welding Technology and its Application in Aerospace Industry
Authors: Zhang Song , Qiao Feng Bin , Guo Li Jie
Published: November 2012

The friction stir welding technology is a new type of welding technology of solid phase, with advantages of high quality, few defects, and small deformation in joint, which has obvious advantages in welding light alloys of aluminum, magnesium and other new materials, which will replace the traditional resistance spot welding and riveting technology to be one of the main manufacturing methods of aerospace industry, and has wide application prospects in this industry, which have great significance in upgrading the manufacturing level of aerospace industry, reduce the production cost and improve our manufacturing technology.
Investigation of Transient Shock Wave in Supersonic Wind Tunnel
Authors: Ghadimi Behnam , Manshadi Mojtaba Dehghan , Bazazzadeh Mehrdad
Published: November 2012

Wind tunnels are the experimental apparatuses which provide an airstream flowing under controlled conditions so that interesting items in aerospace engineering such as pressure and velocity can be tested. In this work, Shock wave passes through the intermittent blow-down wind tunnel at Mach=2,3,4 has been investigated. The shape of the nozzle contour for a given Mach number was determined using the method of characteristics. For this purpose MATLAB code was developed and this code was verified with Osher’s and AUSM methods, FORTRAN code and FLUENT software was used for these two methods, respectively. Dimensions of different parts of wind tunnel are determined and minimum pressure ratio for the starting condition has been founded using FLUENT software. Good agreement was considered compared with the data from eleven tunnels over their range of Mach number.
Influence of the Curved Ground Surface on the Lift of Flat Plate Airfoil
Authors: Chen Shi Shi , Xiong Fen Fen , Frolov Vladimir A. , Li Ke Yong
Published: November 2012

At present, only the flat ground surface problem is investigated in most studies on ground effect, which is not effective for practical applications due to the universal existence of curved ground surface. In this paper, the lift calculation of a two-dimensional flat plate airfoil placed near a curved ground surface is investigated. In order to calculate the complex velocity in the flow field, the complex variable function theory is employed. The conformal mapping method is applied to transform the flat plate airfoil to a cylinder in the uniform flow. Moreover, the discrete vortices method is modified to convert the curved ground surface to a series of discrete boundary elements. Two kinds of curved ground surfaces are considered: semicylindrical hollows and semicylindrical hills. It is shown that the lift fluctuation of flat plate airfoil located near a hollow or a hill is considerably serious, which should be considered during the design of flight vehicles flying near the ground surface.
Studies on Ignition Delay and Flame Spread in High-Performance Solid Rocket Motors
Authors: Aswin C. , Vishnu S. Srichand , Kumar D. Aravind , Deepthi S. , Kumaresh S.K. , Arun M. , Sanal Kumar V.R.
Published: November 2012

Accurate prediction of ignition delay and flame spread rate in solid propellant rocket motors is of great topical interest. In this paper using a standard k-ω turbulence model numerical studies have been carried out to examine the influence of solid rockets port geometry on ignition delay and the flame spread pattern. We observed that with the same inflow conditions and propellant properties heat flux histories and ignition time sequence are different for different port geometries. We conjectured from the numerical results that in solid rocket motors with highly loaded propellants, mass flux of the hot gases moving past the burning surface is large. Under these conditions, the convective flux to the surface of the propellant will be enhanced, which in turn enhance the local Reynolds number. This amounts a reduction in heat transfer film thickness and enhanced heat transfer to the propellant with consequent enhancement in the dynamic burn rate resulting the undesirable starting pressure transient. We concluded that, the more accurate description of gas phase to surface heat transfer process will give a better prediction and control of ignition delay and flame spread rate in solid propellant rockets.
Making an Outer Space Adventure by Means of the Periodic Return of Halley Comet
Authors: Zhu Yun Feng
Published: November 2012

The spacecraft-Pioneer 10 is the first man-made object which flew out of the solar system, you never get it back; the outer space adventure makes Human observe nine planets at close hand by means of the periodic return of Halley Comet, you may get it back. The outer space adventure by the Halley Comet which is safe, economic and environmental protection can explore extraterrestrial civilization.
A Fault Isolation Method Based on Analytical Redundancy Relations for Spacecraft Propulsion System
Authors: Peng Xiao Hui , Yan Zheng , Li Yan Jun , Wu Jian Jun
Published: November 2012

Based on time-varying characters of spacecraft propulsion system, which generates tremendous difficulty to establish diagnostic criteria artificially, the fault isolation method based on Analytical Redundancy Relations (ARRs) generating from Diagnostic Bond Graph (DBG) has been proposed. The ARRs for Spacecraft Propulsion System are built on time-invariant structural characters, which can overcome the challenges from artificially establishing time-varying diagnostic criteria beforehand. By the tendency analysis of the residuals of ARRs, the fault signature matrix can be established. Then faults are isolated by comparison of observed signature and fault signature. Through the analysis of isolation results of a spacecraft propulsion system, it shows that ARRs is valid and practicable at fault isolation with rapid rates.
Development of Efficient Tactile Sensing System for Humanoid Robotics
Authors: Khan Muhammad Imran , Khan Abdul Mannan , Saleem Muhammad Khurram , Nouman Ahmed
Published: November 2012

This paper is related to the development of ASIC for tactile sensing system in humanoid robots. First of all, it is necessary to choose the best sensor for tactile sensing in humanoid robots. A large number of sensors like capacitive, resistive, piezoresistive, tunnel effective, optical, ultrasonic, magnetism based, piezoelectric sensors are available in market for tactile sensing. Not all the sensors are suitable for tactile sensing at all locations of humanoid robotics. We need to use different sensors for different locations in humanoid robotics like fingerprints and belly. Fingerprints of robot are most important part where we need a huge number of sensors on a limited place. As we need a large amount of data for exact modeling of properties contact surface so we require data from a large number of tactile sensors and hence we need to develop an array of tactile sensors.
Robot Manipulators: Modeling, Simulation and Optimal Multi-Variable Control
Authors: Jamali Pouya , Shirazi Kourosh H.
Published: November 2012

In this paper, virtual prototype modeling, simulation and optimization of a 3 DOF SCARA robot as an example of robot manipulators, based on using software packages are presented. The softwares, Solidworks, Matlab and specially its module, Simmechanics, are used for robot modeling and thenMulti-Variable control process is performed with PID controller for controlling the robot. After modeling error RMS is defined as optimization objective function and the controller is optimized by Genetic algorithm. In this way, online kinematics solution in Simmechanics is introduced to avoid mathematical modeling of inverse kinematics problem. The strong point of this work is to facilitate modeling of complex mechatronical systems for engineers and virtual motion visualization of the mechanisms helps the engineers to have better understanding of systems behavior. Using exact numeric prototype of the robot in optimization problem, make it possible to use optimized controller for the actual robot.
A Homogenization Procedure for Nonlinear Free Vibration Analysis of Functionally Graded Beams Resting on Nonlinear Elastic Foundations
Authors: Zerkane Ahmed , El Bikri Khalid , Benamar Rhali
Published: November 2012

The present work deals with a homogenization procedure (HP), which is developed to reduce the problem of geometrically nonlinear free vibrations of functionally graded beams (FGB) resting on elastic nonlinear foundation with immovable ends to that of isotropic homogeneous beams with effective bending stiffness and axial stiffness parameters. The material properties of the functionally graded composites examined are assumed to be graded in the thickness direction and estimated through the rule of mixture. The theoretical model is based on the Euler-Bernouilli beam theory and the Von Kármán geometrical nonlinearity assumptions. Hamilton’s principle is applied and a multimode approach is derived to calculate the fundamental nonlinear frequency parameters, which are found to be in a good agreement with the published results.
Simulation and Optimization Analysis of External Spur-Gear Pump Shell
Authors: Wang Hui , Hou Jing , Sha Yong Dong
Published: November 2012

In order to research the external spur-gear pump shell, use of ANSYS software to make strength analysis, through the simulation to get displacement deformation clouds and equivalent stress clouds,and find shell the maximum displacement deformation position and the maximum stress position.The optimization results show that in the shell security meet conditions, its quality was reduced by 5.9%, the stiffness of the shell has been improved greatly.At the same time,noise of the pump has been reduced, extending the service life of the pump. The study conclusion for improving the gear pump structure design and perfecting its mechanical performance provides theory basis.
Numerical Simulation of Gel Propellant Droplet Breakup in Airflow
Authors: Liu Ze Jun , He Zhen , Wu Jian Jun , Hu Xiao Ping
Published: November 2012

The droplet breakup is of importance in variety of spay combustion field. In order to investigate gel propellant droplet breakup in a gaseous phase, the Navier-Stokes equations in their axi-symmetric form was solved using the finite volume technique, and the Volume of Fluid method (VOF) was employed for tracking the free liquid-gas interface during process of droplet breakup. The results were compared with available published experimental data for Newtonian droplet, and validated the numerical model. The results show that increasing Weber number (We) can accelerate drop breakup; under the low shear rate, increasing K leads to droplet more resistant to breakup, drop breakup is dominated by K value; under the high shear rate, reducing n value results in stronger the shear-thinning behavior, and a decrease in resistant to breakup, n value governs the droplet breakup.
An Empirical Model of Ribbed Cylindrical Glass Reinforced Plastic Tanks
Authors: Noroozi Siamak , Vinney John , Sewell Philip , Khandan Rasoul
Published: November 2012

Ribbed cylindrical Glass Reinforced Plastic (GRP) tanks are currently designed using simplified theory the results of which are then verified by extensive destructive testing. This approach is expensive and can only generate non-optimal design solutions. In addition, there is often a high degree of discrepancy between theoretical and experimental results which necessitates the use of undesirably high factors of safety, which in turn results in the excessive use of material with the concomitant increase in cost, weight and manufacturing time. The primary aim of this investigative research was to develop a more deterministic and accurate design method of predicting the structural integrity and performance of underground cylindrical GRP tanks using non-destructive testing. Linear and non-linear Finite Element Analysis (FEA) techniques, validated against experimental results, were used to analyze a large number of underground ribbed cylindrical GRP tanks. The outcome of which was then expressed in the form of an empirical ‘Design Formula’ which provides a comprehensive solution to ribbed cylindrical GRP tank design for a wide range of tank sizes, laminate lay-ups and material properties. It is intended that the application of this method will eliminate the need for the expensive field tests that are currently required by design codes and standards.
Pressure Control Characteristics Simulation Research of Electro-Hydraulic Proportional Variable Pump
Authors: Wang Hui , Xu Zhuo , Meng Fan Long
Published: November 2012

Based on the theoretical analysis on working principle and motion of the electro-hydraulic proportional variable piston pump, it created and simulated the model in the AMESIM software. The influences of main structural parameters of variable pump on system output dynamic characteristics were revealed after simulating analysis results of pressure control characteristics. And the steady state output of system pressure is proportional to the input voltage of amplifier. The overshoot decreases with the increasing of input voltage, and the response get faster. The damping aperture of proportional reversing valve and core diameter of control plunger have a greater influence on the dynamic response of system.
Tube Hydroforming Analysis Based on Ansys
Authors: Yang Xiao Yu
Published: November 2012

This paper briefly introduces some problems of tube hydroforming process, at the same time, also uses Ansys software to simulate in tube hydroforming process. And draw an conclusion，To avoid defects in tube hydroforming process, the applied internal pressure must be high enough to suppress buckling but not too high to cause bursting.
Research and Simulation on Optimization of Phase Noise in Crystal Oscillators
Authors: Wang Yan , Huang Xian He
Published: November 2012

The methods to reduce phase noise of crystal oscillators based on Leeson model are presented in the paper. According to analysis of Leeson formula, phase noise has a direct relation with noise factor, corner frequency and loaded quality factor. It can be seen that optimization of phase noise can be realized form these three aspects. The feasibility of these methods to reduce phase noise is analyzed. Based on the method of reducing phase noise by improving loaded quality factor, calculation of loaded quality factor is carried out and phase noise of a Butler crystal oscillator is simulated by the Agilent Advanced Design System (ADS). The simulation results prove that this method to reduce phase noise based on improving loaded quality factor is feasible and effective.
Predictions of Scratch Characters for Engineering Material by Using FEM and Abductive Network
Authors: Yang Tung Sheng , Chang Sheng Yi , Chou Jian Chang
Published: November 2012

Scratch test is mainly used to study mechanical properties of materials near their surface. This study applies the finite element method (FEM) in conjunction with an abductive network to predict the scratch character such as rear contact angle, shape ratio and hardness for strain hardening bulk material of scratch process. To verify the prediction of FEM simulation of scratch process, the experimental data are compared with the results of current simulation. A finite element analysis is also utilized to investigate the material properties on side view contour, rear contact angle, hardness and shape ratio. Additionally, the abductive network was applied to synthesize the data sets obtained from the numerical simulation. The prediction models are then established for the rear contact angle, hardness and shape ratio of nanoscratch process under a suitable range of material parameters.
Magnesium Alloy Stent Expansion Behavior Simulated by Finite Element Method
Authors: Iqbal Sabir Muhammad , Liu Er Bao , Li Zhen , Zheng Yu Feng , Li Li
Published: November 2012

Biodegradable magnesium alloy stents have gained increasing interest in the past years due to their potential prospect. Magnesium alloy is brittle compared with stainless steel. This means it has less elongation than other stent materials and it may cause strut break under large deformation. In this paper, a finite element model for magnesium alloy stent is studied to simulate the mechanical behavior of the stent. It is composed of 1.5mm in inner diameter, 7mm length, 80µm thickness and 110µm in cross-sectional width. Six mechanical properties have been studied by mathematical modeling with determination of: (1) stent deployment pressure; (2) the intrinsic elastic recoil of the material used; (3) the stent foreshortening; (4) the stent coverage area, (5) the stent flexibility; and (6) the stress maps.
Data Acquisition and Power Forecasting of Trans-Regional Wind Farm
Authors: Wang S.X. , Lv D. , Liu Z.Y. , He F.
Published: November 2012

For the geographical dispersion of wind farms, an effective and reliable platform of data transmission and storage based on VPN private tunnel and PI database is built to solve information sharing and centralized power forecasting. Then the real-time data which wind speed is predicted by ARMA model and predictive power through the wind-power model is built by neural networks is published. The simulation results indicate the forecasting system is conducive to ensuring the stable and secure running of the grid and improving the utilization rate of wind power.
A New Approach about Heat Transfer of Hot-Wire Anemometer
Authors: Manshadi Mojtaba Dehghan , Esfeh Mohamad Kazemi
Published: November 2012

The hot-wire anemometer is a famous thermal transducer for turbulence measurements. The fundamental principle of hot-wire anemometer is based on the convective heat transfer, since the heat transfer is directly proportional to the temperature difference between the sensor and the fluid, hence ambient temperature variations are one of the most important error sources in the measurements with the hot-wire anemometers. Many methods have been proposed to compensate for the ambient temperature variations. In such methods the effect of temperature drift is only considered and the effect of Nusselt number is ignored. In the present research the effect of air flow temperature variations on the response of constant temperature anemometer has been studied experimentally. Furthermore, with the basis of air flow velocity and ambient temperature variations, the percentage errors in velocity measurements have been estimated. Finally, based on achieved results, an accurate method has been proposed to compensate the air flow temperature variations.
Study of Hydrogen-Air Flame Stability with Different Initial Pressure
Authors: Liu Xing Hua , Liang Hong , Fan Zhi Qiang , Wang Dao Jing
Published: November 2012

Hydrogen-air flame stability with different initial pressures is studied in a constant volume combustion cell. The schlieren flame images and the pressure curves are obtained under various initial pressures, equivalence ratios and initial temperatures. The results show that the time of the laminar flame stage is decreasing with the increasing initial pressure. The main reason of the rapid increasing pressure is whether the squish flame appears. The squish flame stage does not occur when the value of the initial pressure is very low. At this time, the varibility of the pressure is very low. The pressure oscillation occurs when the squish flame or the main flame transmits to the under wall surface. Meanwhile, under the different initial conditions, the time of the mixture combustion process stages is often different, and the flame stability is different. At the same time, the flame crtical radius is decreasing when the initial pressure is increasing.
Analysis of a Roll Cage Design against Various Impact Load and Longitudinal Torsion for Safety
Authors: Naiju C.D. , Annamalai K. , Nikhil Prakash , Bevin Babu
Published: November 2012

This study is aimed at carrying out a finite element analysis on a roll cage of a vehicle used for student competitions around the world. The design process was carried out using a CAD package and analysis was done using finite element analysis software, ANSYS. Impact test was carried out on the roll cage under different conditions and the effect on the structural members are studied and discussed. The results are very much helpful and assure that the car is in safe condition in case of a crash or accident. Finite Element Analysis (FEA) is also carried out with the frame against torsional loading. Two different materials were considered for the analysis. The results of displacement of frame, nodal solution, element solution and bending moment are discussed.
Knowledge Based Engineering Optimization and Interoperability: An Automotive Case-Study
Authors: Danesi Frederic , Gardan Nicolas , Kwassi Elvis
Published: November 2012

This article focuses on the optimization of a design process, in the context of automotive subcontracting opportunity. This optimization is guided by the underlying manufacturing process and by the industrial knowledge. We first show that the actual design studies are biased by the final goal (a formal design) and do not take into account early industrial needs (a draft design to draw up an estimate). We then demonstrate how an automaker subcontractor optimizes the early design process thanks to industrial knowledge.
Reconfiguration of a Milling Machine to Achieve Friction Stir Welds
Authors: Akinlabi Esther Titilayo , Madyira Daniel Makundwaneyi , Akinlabi Stephen A.
Published: November 2012

This paper reports on the reconfiguration of a milling machine to produce friction stir welds of aluminium and copper and friction stir processing of 6086 aluminium alloy. Friction stir welding tools were designed and manufactured from tool steel. The tools were inserted into the chuck of the milling machine. A backing plate was also specially designed and manufacturedfrom mild steel to protect the milling machine table and was placed on the bed with the use of T-nuts. The plates were secured firmly on the backing plate with the use of specially designed clamping fixtures. The varied welding speeds and the rotational speeds were achieved using the control system on the vertical milling machine. The reconfigured milling machine was successfully employed to produce friction stir processing of aluminium and friction stir welds of aluminium and copper. An optimum joint strength of 74% was achieved.
Analysis of Companding Techniques Applied to Onboard Telemetry Systems
Authors: Lucks Marcio Barbosa , Procópio Heuller A.C.
Published: November 2012

In order to increase the dynamic range and the signal-to-quantization noise ratio (SQNR) of telecommunication systems, companding techniques were developed, such as the μ-law and the A-law. These techniques allow a non-uniform quantization of the signal using a compressor circuit followed by a uniform quantizer in the transmitter and the reconstruction of the original signal on the receiver by means of an expander circuit. Some types of signals monitored during the flight of sounding vehicles and satellite launchers have a very wide dynamic range. In this paper, we propose and analyze the use of companding techniques in order to improve the SQNR of onboard telemetry systems.
Quasi Static Fracture – Global Minimizer of the Regularized Energy
Authors: Hentati Hamdi , Abdelmoula Radhi , Maalej Aref , Maalej Khalil
Published: November 2012

Fracture mechanics has been revisited aimed at modeling brittle fracture based on Griffith viewpoint. The purpose of this work is to present a numerical computational method for solving the quasi static crack propagation based on the variational theory. It requires no prior knowledge of the crack path or of its topology. Moreover, it is capable of modeling crack initiation. At the numerical level, we use a standard linear (P1) Lagrange finite element method for space discretization. We perform numerical simulations of a piece of brittle material without initial crack. We show also the necessity of adding the backtracking algorithm to alternate minimizations algorithm to ensure the convergence of the alternate minimizations algorithm to a global minimizer.
Numerical Simulation and Design of Flow Field of Water-Cooled Roller Based on FLUENT
Authors: Zhou Xiong , Wan Er Ping , Zhang Peng
Published: November 2012

Water-cooled roller is the core component of the production of negative plate of electrolytic lead, and the thickness and uniformity of negative plate of electrolytic lead is determined by flow field of internal cooling water of water-cooled roller. In order to catch the distribution of flow field inside of water-cooled roller and guide the design, the moving reference frame technology in fluent software is used to numerically simulate the 3d flow in water-cooled roller and display the characteristics and state of the flow inside the water-cooled roller Intuitive. The optimal aperture of water hole is obtained through the contrastive analysis of simulation of different apertures of water holes. The performance of water-cooled prototype meets the requirements of field investigation, also the thickness and uniformity of negative plate of electrolytic lead meet production requirement.
DSPACE Implication of HILS for Mill Control System
Authors: Zhang Wei , Wang Yu Ming
Published: November 2012

Dspace HILS platform is used to realize the real-time test of the mill control system.In this platform, a real controller is the part of the control system. DSPACE real-time simulation and computer real-time running control the object model to virtual out a rolling mill, which realizes the mill the real-time closed-loop test of control system.Yanshan University 300 reversible rolling mill as the object of experimental platform is established and verifies the feasibility and validity of the simulation platform.
Simulation and Analysis on Main Synchronized Hydraulic Cylinder of Huge Hydraulic Press
Authors: Yu Jin , Fan Ming Zhen , Huang Guo Qin , Yu Min
Published: November 2012

Nowadays, huge hydraulic press plays an important role in the heavy industry. The synchronized hydraulic cylinder is the key component, which will affect the performance of the press. Thus, a thorough investigation to the main cylinder is required. In this paper, a mathematical model was built for the position closed-loop control of active synchronous hydraulic cylinders, and transfer function of the corresponding single cylinder was deduced. Simulation and calibration of the working cylinder servo position control system was accomplished with MATLAB, so as to improve the response speed and stability of the single working cylinder system. The results showed that a single hydraulic piston cylinder had a better position control features, which offered a theory basis for the design of the main drivers of forging hydraulic machine synchronization system.
The Modeling and Simulation of Water Hydraulic Overflow Valve with Giant Magnetostrictive Actuator
Authors: Zhang Yi Bo , He Zu Shun , Yuan Rui Bo , Zhang Li
Published: November 2012

This paper puts forward the structure of water hydraulic overflow valve with Giant Magnetostrictive Actuator. In the condition of ignoring magnetic leakage and magnetic force uneven, we deduced the static output displacement and force equation of the GMA. By establishing a mathematical model, we get the dynamic response of the time and output force in the rated electricity flowing down with the simulation. GMA has the simple structure, good linear, enough output force and displacement, and high response speed and other significant advantages.
Mechanical Model of Nonmagnetic Mineral Particles in Magneto Hydrostatic Static Separation
Authors: Zhang Ying Qiang , Wei Jing Tao , Wang Ting You , Wu Zhang Yong
Published: November 2012

Base on the fluid dynamics，electromagnetism，Newton’s law and some other basic theories，the paper analyses the equations of motion and Bernoulli for nonmagnetic mineral particles in magnetic fluid. And apply these theories to establish the mechanical model for the nonmagnetic mineral particles in magneto hydrostatic static separation (MHSS). In MHSS, the particles would be stressed by gravity force, magnetic buoyancy, ordinary buoyancy, etc. The wedge-shaped magnetic poles can set up the magnetic buoyancy of which direction is straight up, and the levitation force could be stronger in ferromagnetic fluid. And it can be calculated equating normal buoyant weight to the magnetic buoyant force that any nonmagnetic substance can be floated in magnetic fluid. The paper also analyses some parameters that affect the separation result, such as the magnetic field intensity and the magnetic field gradient. These tasks may give some supports for MHSS applied in industrial.
Optimal Design for the Hydraulic AGC System of Thick Steel Plate Miller
Authors: Ding You Qing , Wang Pei Feng
Published: November 2012

This paper briefly describes the affecting factors and the key features of the hydraulic AGC system of thick steel plate miller. According to the research on the use and maintenance of the hydraulic AGC system of thick steel plate miller, the optimal design about the AGC servo cylinder, the system power source and the AGC servo control section of the hydraulic AGC system of thick steel plate miller has been given.
Research on Intake System of Motorcycle Engine to Obtain High Torque at Low and Medium Speed
Authors: Huang Qi , Li Yun Qing , Liu Cheng Kei , Lai Xiao Li
Published: November 2012

The new intake system is designed and the intake pipe is changed in order to get high torque at low and medium speed. After the intake parameters are changed, the intake dynamic effect is utilized to increase volumetric efficiency and torque at the low and medium speed by theory analyses. Through further research, it is found that intake pipe length has a quite great influence on torque characteristic. Extending intake pipe length can improve engine torque at low and medium speed and its maximum torque point is shifted from high speed scope to low and medium speed scope.
Application of DC Motor Digital Speed Control System in Submerged Arc Welding Machine
Authors: Zhang Gang , Zhu Jian Qu
Published: November 2012

Abstract: In the current domestic control system of submerged arc welding machine, most walking DC motor speed control uses the method of analog control pulse width modulation (PWM), which has a complex circuit, high failure rate and is inconvenient to use. For this phenomenon, DSP (TMS320F2812) disc is used to build a digital control system, and replace the traditional analog controller, allowing the weld control system more simple and practical. The main content of this paper is the hardware circuit design and software algorithms programming of digital control DC speed control system. Tested by experiment, this digital control system can replace the weld analog control system, enabling the motor to have good control performance at low speed thereby enhancing the welding effect of submerged arc welding machine.
Optimization on Engine Mounting Based on Energy Decoupling Technique
Authors: Zhang Yan Fang
Published: November 2012

Decoupling analysis on engine mounting is based on energy decoupling technique, and optimization program is proposed by adjust mounting position and stiffness. The results showed that decoupling of after optimization is better than that before optimization, which is a basis for further improving on isolation performance.
Simulation of Utilisation of Pressure Propagation for Increased Efficiency of Secondary Controlled Discrete Displacement Cylinders
Authors: Hansen Rico H. , Hansen Anders , Andersen Torben O.
Published: November 2012

A key component of upcoming secondary controlled fluid-power systems for e.g. wave energy is the implementation of discrete force control of cylinders by discrete variation of the cylinder displacement. However, as the discrete control is implemented by shifting between fixed system pressures in multiple cylinder chambers using on/off valves, the energy efficiency of the performed shifts is essential for the total system efficiency. However, pressure shifting on a volume, where the dynamics of pressure propagation in the pipelines is negligible have been proved to have an unavoidable minimum loss due to the compressibility of the fluid. This paper performs a simulation study, showing that an improved energy efficient shift may be implemented by utilising the pressure propagation in the line between valve and cylinder chamber.
The Optimization Design of Brake System in Mine Dump Truck
Authors: Zhao Jing Yi , Zhang Chun Hui , Guo Rui , Han De Cai , Wang Yong Chang
Published: November 2012

On the base of introducing the principle of the brake system of mine dump truck,the in fluence factors of the brake performance are analysed.In order to further reduce the brake distance to meet the requirements of actual use,the improvement plan is presented for brake system opti mization and the field test is made.The results show that the brake duration of the brake system is re duced after the optimization and the performance is improved which is of great practical significance.
Prediction of High Temperature Flow Stress for AISI 4120 Steel during Hot Compression
Authors: Zou Ming Ping , Xu Wu Jiao , Wang Peng Cheng
Published: November 2012

To investigate the hot deformation behaviors of AISI 4120 steel, isothermal compression tests were conducted using Gleeble-1500 thermal-mechanical simulator in the temperature range of 1073-1373K with the strain rate of 0.01-10s-1. The hyperbolic sine law in Arrhenius type is used in the constitutive modeling for AISI 4120. The influence of strain is incorporated in constitutive analysis by considering the effect of strain on material constants α, n, Q and ln A. The flow stress values predicted by the developed constitutive equations show a good agreement with experimental results, which reveals that the developed constitutive equations could give an accurate and precise prediction for the high temperature flow behaviors of AISI 4120 steel. The predictability of developed constitutive equation was further quantified in terms of correlation coefficient (R) and average absolute relative error (AARE). The R and AARE were found to be 0.9847 and 8.0372% respectively, which reflects the good prediction capabilities of the developed constitutive equation.
The Research of Industrial Robots Design Based on Synchronous Technology
Authors: Wang Xue Jun , Chi Yi Lin , Li Fu Yu , Gao Li , Peng Yong Xin
Published: November 2012

Industrial robots are widely applied in all kinds of automatic production line. It is the most important members in the family of robots. To improve the product quality and the precision of the robots, in addition to control strictly the production techniques and monitor its manufacturing process, the most important is to improve the design level and the design efficiency. In this paper, a new type of automatic four degrees of freedom industrial robots will be studied by using Solid Edge ST4 3 d synchronous modeling technology. In the process of design, synchronous modeling, parallel design, cooperative modeling technique and Top-down Assembly Modeling technology are combined with during the design. The whole product modeling design has included module and subsystem, has accomplished chassis module, and turn arm module and grab module design. The key point in this paper is that synchronous modeling technology is used in the three dimensional modeling the design application, and shows that the technology in different modules and the union between different designers. The results show that all the technical application above can improve the design efficiency, reduce design error and design iterative process, thus greatly improve the product quality and production efficiency
Modeling and Simulation of Hydraulic Wind Turbine
Authors: Zhang Yin , Kong Xiang Dong , Ai Chao , Cai Wen Jian
Published: November 2012

The wind energy can be transferred through an intermediate medium such as hydraulic fluids. In this paper a hydraulic system is utilized to transfer the wind energy from a wind turbine to a synchronous generator. A close loop hydraulic transfer system with fixed displacement pump and variable displacement motor is introduced and the mathematical model is obtained. The simulation of the hydraulic wind turbine is derived by using the SimHydraulics toolbox of MATLAB and AMESim. The simulation results demonstrate the effectiveness of the modeling and are useful to design the control system.
Analysis of Water Jacket Furnace Air Coil Blockage
Authors: Chen Yu , He Yun Bing , Wang Tao
Published: November 2012

Water Jacket Furnace is a kind of indispensable equipment in the process of oil and gas field production, gathering and transportation. It is mainly responsible for the warming and energy supply of gathering and transportation system. After production, the oil of natural gas firstly enters the Water Jacket Furnace for pressure regulation, thermal insulation and then received the processing of separation, filtration, pressure regulation and metering; natural gas containing more impurities will gradually form sediment and eventually block the snakelike coil, resulting in Water Jacket Furnace heat exchange failure; with the continuous development of the oilfield construction, the application of Water Jacket Furnace continues to increase, and the blockage phenomenon gradually increases in correspondence; under the circumstance of being unable to solve the Water Jacket Furnace blockage by high pressure differential, this paper presents the operation method of blockage solution via fresh water injection for discussion.
The Research on Material Balance Considering In-Seam and Intrabed Water
Authors: Yu Xi Nan , Liu Hong , Cao Ji Hua , Pang Jin
Published: November 2012

The material balance equation of water-drive gas reservoir does not study the effect of in-seam and intrabed water,which results the distortion of reserve.If we take acount of the effect of in-seam and intrabed water,the slope of material balance equation curve is over the back-face,and the dynamic reserve is lower than ignoring the effect of in-seam and intrabed water,the average value of dynamic reserve drops 12.16%,so we must take acount of the effect of in-seam and intrabed water to the dynamic reserve.
Development Practices of the Pump Performance Test Bed for Agricultural Sprayers
Authors: Yang Meng Tao , Jin Hong Wei , Wang Xiao Mei , Yang Yong Gang
Published: November 2012

Based on the development practice of the pump performance test bed for the agricultural sprayer, a new program is proposed to cover the integrated mechanical structure of the pump performance test bed. Analysis was given to the various performance parameters of the pump test with regard to their testing methods, and specific methods of work performance test and inhalation performance test were also discussed to explore the test results. Finally, the issues that need to be focused were raised on the design and manufacture of pump performance test for the sprayer.
Dual-Pump Hydraulic Hybrid Excavator with Combined Common Pressure Rail and Valve-Controlled System
Authors: Shen Wei , Jiang Ji Hai
Published: November 2012

To solve the low efficiency problem of hydraulic excavator, one type of Dual-Pump hydraulic architecture with combined Common Pressure Rail (CPR) and traditional valve controlled system is presented. Firstly, we analyze the energy consumption of excavator during one cycle to know the energy distribution among each actuator. Then, the Dual-Pump system is explained to design an easy to modify, cost efficient hydraulic hybrid excavator. Moreover, we focus on the boom system and construct the model. Finally, a simulation is created and the results illustrate that the proposed system can satisfy the design requirement.
Study on Variable Universe Fuzzy PID Control for Landing Gear Based on MRF (Magneto-Rheological Fluid) Damper
Authors: Zhu Shi Xing , Chen Chan Juan
Published: November 2012

Aircraft landing gear shock system model was established, The system vibration differential equation and state-space equation were deserved。Based on the general fuzzy PID controller, the idea of fuzzy PID controller and its application in shock absorber system were studied. Based on MATLAB, the system simulation model was established, and the fuzzy PID control of semi-active suspension is analyzed compared to variable universe fuzzy PID control. The results show that the variable universe fuzzy PID control had better control effect.