bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Study on the Cutting Performance of Ultra-Precision Micro Milling Machine
Authors: Zhang Peng , Lu Li Hua , Wang Bo , Liang Ying Chun
Published: March 2010

To meet the requirement for the machining of the ultra-precision, ultra-smooth and micro-structure surface, an ultra-precision three axes micro milling machine was developed with the positioning accuracy better than ±0.25μm and the repetitive positioning accuracy better than ±0.2μm of all the three axes. The machine is proved to achieve the nanometer scale step response. Through milling experiments with micro-diameter tungsten carbide milling tool, the cutting performance has been further proved: the milling accuracy of 50μm-high step on the workpiece of aluminum alloy is better than ±0.3μm; and the 3D surface of pure copper workpiece is as smooth as mirror, with a roughness reaching 40nm. At last, the thin-walled structure of 10μm thickness on the workpiece of aluminum alloy is milled.
Investigation on Thermomechanical Treatment of PM FGH4096 Superalloy
Authors: Ning Yong Quan , Yao Ze Kun , Xie Xing Hua , Guo Hong Zhen
Published: March 2010

Thermomechanical treatment (TMT) of PM FGH4096 superalloy were carried out to futher improve the mechanical strength and refine the γ’ particle, and this processing route as follows: near-isothrmal forged at deformation temperature of 1130°C and strain rate of 0.1 s-1, followed by subsequence oil quenching, and then held at 760°C for 16 h. OM, SEM and TEM were used to investigate the microstructure of TMTed alloy. It was found that the advanced mechanical strength originated form the dispersion strengthening of fine γ’ particle and stain hardening reserved from deformation after TMT. But TMT had no obvious effect on improving the chemical segregation of original materials. Fracture analysis of TMTed alloy shown that cracks origined from Ti and Nb chemical segregation and presented rose-pattern and ladder-pattern at room temperature and 750°C temperature.
Finite Element Simulation of Temperature Field in Fused Deposition Modeling
Authors: Ji Liang Bo , Zhou Tian Rui
Published: March 2010

Taking into account temperature-dependent thermal conduction and heat capacity, based in the research on the physical property of the material of Acrylonitrile Butadiene Styrene (ABS), a three-dimensional transient thermal finite element model has been developed in Fused Deposition Modeling (FDM). The moving material of ABS by the sprayer on the mold equipment is simulated with the employment of ANSYS parametric design language (APDL) and latent heat is considered by using enthalpy. By the technique of element live and die on ANSYS software and using the nonlinear finite element method, several conclusions according to the simulation results were produced, first of all, the simulation result shows that the temperature field distribution likes an ellipse; secondly, comparing with the previous track, the latter one has larger heat affected region and larger inhomogeneous temperature distribution; the greatest temperature gradient takes place near the edges of deposited part where the sprayer scanning direction changes.
Investigation on the Formability of Tailor-Welded Blanks
Authors: Tian Hao Bin , Liu Xiao Hang , Lin Jian Ping
Published: March 2010

Tailor-welded blanks (TWB) have been widely used in automobile industry. In this paper, expanding experiments are carried out for tailor-welded blanks both with curved seams and straight seams, and the formability of tailor-welded blanks with curved seams has been studied and compared with tailor-welded blanks with straight seams. The effects of thickness ratios and seam radius on the formability of tailor-welded blanks with curved seams and straight seams are deduced, separately. In the end, the relationships between the shapes of welding seams and forming heights, and relationships between the thickness ratios and forming heights are given, which are valued to the designers and processers of tailor-welded blanks.
Analysis of Assembling and Working Stress of Compound Rings High-Pressure Vessel of 5GPa
Authors: Rao Jian Hua , Shen Q.F. , Wang C.
Published: March 2010

To improve the working performance of the compound rings high-pressure vessel, the different assembly and structural parameters during the process of radial and axial preloading have been analyzed with the finite element method. The simulation analysis on the assembly process of room temperature press-fitting has been carried out based on the theory of contact problem with friction, and it is found that the tangential compressive prestress is uneven under the influence of friction coefficient and conicity of fitting surfaces. The main effect factors of horizontal fracture of cemented carbide core are also analyzed. Furthermore, the results of reducing the axial stress of core by different ways of applying end pressure are compared. These studies provide the guidance for the improvement in design and manufacture of compound rings.
Effects of Opening Hole Geometric Parameters on Hole-Edge Stress Field of Plates According to a Complex Variable Function Model
Authors: Li Cheng , Tie Ying , Zheng Yan Ping
Published: March 2010

Mapping functions of various ellipses are gained by complex function theory. Applying stress function with complex variables, a mechanical model of the stress field and the stress components near the hole is presented. The influences of three different geometric parameters of elliptic hole on stress around hole are discussed subject to bending moment. The results show that the length of long axis and short axis is more uniform, the peak stress around hole edge is greater. The work above will provide theory references on choosing hole shape in practical engineering.
Simulation and Optimization on the Injection Molding for Auto-Bumper
Authors: Geng Tie , Zhang Jia Min , Wu Rong Ren , Shan Yan
Published: March 2010

The structure and process of the injection mould for the front-bumper of a car were optimized with the domestic 3D flowing simulation software HSCAE3D. Through the analysis and comparison of several different schemes, optimal design is achieved.
Simulation Study on Magnetic Field Characteristics of High Magnetic Field Intensity Permanent Magnet Magnetic Filter
Authors: Jiao Hong Guang , Liu Peng , Tie Zhan Xu
Published: March 2010

To solve the conflict between separation space and magnetic field intensity, an original magnetic circuit structure system of permanent magnet magnetic filter is designed by utilizing multi-dimensional magnet extrusion technologies, with multi-block NdFeB magnets of different structures and magnetization directions. The inside diameter of the ring magnets and ring soft iron is taken as separating space. To inspect the distribution of the magnetic field characteristics of magnetic circuit system, mathematical model is established, and the designed magnetic circuit system is simulated, taking advantage of the electromagnetic software Magnet. The simulation results show that a larger separating space and higher background magnetic density can be achieved simultaneously by means of the organic magnetic circuit system design, when the thickness of ring soft iron is 4mm and the diameter ratio (outside diameter to the diameter) of ring magnets is 10/3. The highest magnetic induction intensity of 29.2 mm separating space is 1.5T, which provides the basis for permanent magnet magnetic circuit design.
Springback Prediction of Axial Symmetry Sheet Part Drawing
Authors: Guo Mei Ling , Wang Xin Yun , Luo Jian Cheng , Xia Ju Chen
Published: March 2010

Springback in drawing of an axial symmetry sheet metal part was studied. First of all, according to a springback formula of simple bending, the moment was modified by concerning of axial symmetry shape of part to construct a formula for predicting the springback. Then, springback process was analyzed with FE software Dynaform. Finally, drawing experiment was carried out. Use the reverse engineering and software Geomagic to obtain the shape and springback of the part. Excluding errors of measurement and simulation, the results of experiment and finite element simulation and predictive model were compared, and it shows that the predictive model works well.
Higher Order Harmonic Wave and its Effect on Thermosonic Bond System
Authors: Li Zhan Hui , Wu Yun Xin , Long Zhi Li
Published: March 2010

Thermosonic bond is widely used in package of semiconductor chip due to its advantages, such as simple process, high efficiency, and no pollution. Ultrasonic play important role inspired interconnection interface atomic energy and soften metallic materials in thermosonic bond. The vibration of bond tool is nonlinear and bond strength is unstable with contact interface condition changing due to discontinuity characteristic parameters of contact interfaces. In order to improve bond strength of chip, model of ultrasonic propagation across a rough contact interface was established. Aluminium wire bond was performed on a thermosonic bond test platform. The harmonic waves of bond tool and the bond strength were measured. The experiment results show that the best bond strength and the less higher order harmonic is achieve when the contact interface pressure is in moderate range.
The Fatigue Life Prediction of Pistons Based on the Cumulate Damage
Authors: Wang Yan Xia , Liu Yong Qi , Shi H.Y.
Published: March 2010

In this study, the FEA static and dynamic analysis for one type of piston are carried out by using software ANSYS to obtained the cranny origin position and stress range value of the dangerous part of the piston, respectively. The critical crack length is analyzed based on the fatigue theory; the stress intensity factors (SIF) are computed, and the expression of the shape geometry factor of the piston is obtained according to the least squares method. An estimated formula of the fatigue life is developed by amending the Paris formula on the basis of studying the fatigue behavior of pistons. Finally, the fatigue cracked life of the piston is calculated using these parameters and the Amending Paris formula.
Research on the Fault Diagnosis of Trenchless Drilling Pneumatic Impact Device Based on Grey Relational Theory
Authors: Zhang Jian , Rui Yan Nian , Chen Jie , Duan Xiao Ren
Published: March 2010

Recently the technology of the trenchless drilling of road construction is developing fast as a new technology. However the problem of fault diagnosis in the trenchless drilling pneumatic impact device which works under ground puzzles users frequently. Combined the traditional vibration diagnosis technology with the grey relational theory, a novel grey fault diagnosis approach is presented. With the grey relational degree used to make cluster analysis, the on-line monitoring and diagnosis is realized. The experiment results show that this method is highly reliable and the stucture is very simple.
Study on On-Machine Measurement of Rotating Tools Based on Image Processing
Authors: Zhao Wen Hui , Duan Zhen Yun , Zhao Wen Zhen , Liu She
Published: March 2010

It is necessary to develop an on-machine measurement system of cutting tools with high precision and high efficiency on the NC machining, so that it can decrease non-production time and improve machining efficiency. A system for high precision measurement of rotating tools on the basis of image processing is described in this paper. Images are acquired from a digital camera and transmitted into a computer. The working profile of rotating tools and geometrical parameters are extracted accurately through image processing technology. Depending on theoretical analysis and experiments, this system can be widely applied to tool offset and NC programming based on working profile of the tools.
The Series-Parallel Robot Coordinates Polishing System Based on the Multi-Agent
Authors: Yu Miao , Ma Shi Qiang
Published: March 2010

This paper puts forward a multi-Agent alliance control model that is made up of the series robot Agent, the parallel moving platform Agent and the polishing tool system Agent and so on by organically introducing the MAS (Multi-Agent System) theory into the polishing. Through the introduction of point-curve constraint, the dynamics equation of the constraint multi-body for the polishing system is established in order to accurately program the moving track of the robots. Meanwhile, the control parameters during the polishing can be optimized and the foundation can be afforded for carrying out the collocation of the optimal parameters with the series-parallel coordinates polishing and programming the optimal path on the free-form surface.
Analytical Model of Thermal Stress for Encapsulation and Service Process of Solar Cell Module
Authors: Sun Guo Hui , Yan Shi Lin , Chen Gang
Published: March 2010

A significant challenge in encapsulation process of solar cell module is to reduce breakage rates. In encapsulation and service process of the solar cell module, since the mismatch of heat expansion coefficients of various materials, and temperature difference of material interface in service of module, the residual stresses is caused in each material layer of solar cell module. Analytical model was established to analyze the distribution of temperature and residual stress in encapsulation and service process of the solar cell module. The validity of the analytical model is verified by comparing with finite element method (FEM) results. The residual stresses are obtained during encapsulation of solar cell module, and the thermal stress is reverse in encapsulation and service process of the solar cell module. The effect of thermal stress on structure strength of solar cell module is discussed in detail.
Dynamic Decoupling Control of Electro-Spindle Supported by AC Hybrid Magnetic Bearings Based on Neural Network Inverse Method
Authors: Zhang Wei Yu , Zhu Huang Qiu , Yang Ze Bin
Published: March 2010

A dynamic decoupling control method based on neural network inverse system theory is developed for the 5 degrees of freedom (5-DOF) rotor system. The rotor system suspended by AC hybrid magnetic bearings (HMBs) is a multivariable, nonlinear and strong coupled system. Firstly, the configuration of 5-DOF HMBs and the mathematical equations of suspension forces are set up. Secondly, it is demonstrated the system is reversible by analyzing mathematical model. On the basis, the neural network inverse system which is composed of the static neural networks and integrators, and original system are in series to constitute pseudo linear systems. Finally, linear system theory is applied to these linearization subsystems for designing close-loop controllers. The simulation results show that this kind of control strategy can realize dynamic decoupling control, and control system obtains good dynamic and static performances.
Strength Analysis of Coiled Tubing in the Injector
Authors: Liang Zheng , Mao Huai Xin , Zhao Guang Hui , Jiang Fa Guang
Published: March 2010

Coiled tubing (CT) injector head is a key part of CT unit. Friction between gripper blocks and CT offers axial force that runs and retrieves the CT into or out of the wellbore. The CT held by the gripper blocks is loaded by axial force, pressure of inner fluid and gripping force, and is in a complex forcing state. Here it was assumed that all stresses were invariable longitudinally and could be simplified as problem of plane strain. The gripping force acted on the outer surface of CT was set as sinusoidal function along circumference. Stress function was employed to deduce the stress state of CT in gripper blocks. The effects of gripping force, inner pressure and axial force on CT strength were studied, and yield limit curves of the CT were presented by Mises yield criterion. These results offer referring data for minimizes the risk of scarring or mashing the CT.
Mathematical Model for Closed-Form Solution of Parameters of Cylinder Exhaust Port in Variable-Stroke Engine
Authors: Di Li Ming , Yang Chun Jing , Zhao Yong Sheng
Published: March 2010

A mathematical model for getting the closed-form solution of main parameters of cylinder exhaust port is present, based on a few known parameters of variable-stroke engine (VSE). Considering lack of parameters in the initial stage of design, empirical formula is applied to solve the initial specific time-area value of exhaust port, and the initial port timing angle is solved by using logarithmic alignment method, thereby height and width of the exhaust port can be solved, then the precise specific time-area value and port timing angle are solved by using the coefficient calculation method and logarithmic alignment method respectively, so that the relative errors between initial and precise values of specific time-area value and port timing angle are defined as the relative errors of the mathematical model. Application examples show that the relative errors of the model is less than 3%.
Digital Manufacturing System of Aircraft Wing Integral Panel
Authors: Liu Chuang , Wang Jun Biao , Zhang Xian Jie
Published: March 2010

The function model of digital manufacturing system of aircraft wing integral panel is proposed using IDEF0. The digital integral panel manufacturing subsystems including process design, manufacturing model definition, tooling design and manufacturing, process information management, fabrication and inspection are described. In this system, the integral panel is formed by shot peen forming process, and the corresponding approach to solve some key manufacturing problems is described. The part manufacturing model is presented to represent the intermediate part in the fabrication process. The information flow model of the system is built. The application of the system into engineering is analyzed, and it is shown that digital manufacturing of wing integral panel can shorten the cycle, lower the cost and improve quality.
Effects of the Gear Tooth Modification on the Nonlinear Dynamics of Gear Transmission System
Authors: Chen Si Yu , Tang Jin Yuan , Luo C.W.
Published: March 2010

The effects of tooth modification on the nonlinear dynamic behaviors are studied in this paper. Firstly, the static transmission error under load combined with misalignment error and modification are deduced. These effects can be introduced directly in the meshing stiffness and static transmission error models. Then the effect of two different type of tooth modification combined with misalignment error on the dynamic responses are investigated by using numerical simulation method. The numerical results show that the misalignment error has a significant effect on the static transmission error. The tooth crowning modification is generally preferred for absorbing the misalignment error by comparing with the tip and root relief. The tip and root relief can not resolve the vibration problem induced by misalignment error but the crowning modification can reduce the vibration significantly.
The Numerical Simulation of Air Bulge Forming of Profiled Can
Authors: Jin Jie , He Xin
Published: March 2010

Air bulge forming is a forming process where an inner pressure deforms the material to the shape of a die cavity. The main concerns about such a process of profiled cans are to avoid wall thickness reduction, wrinkling and bursting. The success of this process strongly depends on the choice of process parameters, i.e. the properties of material, thickness and inner pressure. By transforming the problem into a deformation controlled rather than a force controlled process, the results from the process parameter estimation become more reliable but on the other hand less intuitive. In this context, the influence of materials, friction coefficient, transitional fillet radius, thickness and bulging load are studied and some suited technological parameters and forming rules are obtained. The most important point is that the simulation and results of experiments are probably consistent.
The Crystal Structural Properties of Sputtered ZnO Films Containing Internal Stress
Authors: Huang Bo , He Guan Nan , Yang Hui Dong
Published: March 2010

The ZnO films were deposited on Si substrate by radio frequency (RF) magnetron sputtering. The effects of the Ar/O2 ratios on the structural characteristics and the internal stress in the ZnO films have been studied. The SEM images shows that the ZnO grains are nano-sized and tightly packed. The ZnO films are highly c-axis oriented with the (002) plane parallel to the substrate. The samples has a stress of the order of 1.0 × 1010 dyn/cm2. It is found that the size of ZnO crystal grains distinctly depends on the stress in the ZnO films. In order to deposite ZnO films with good crystalline quality, the stress caused by the growth process can be depressed by adjusting the Ar/O2 ratios.
Research & Realization on Neural Network for Forecast of AM Automatic Logistics Information-System
Authors: Wei Wei , Song Chong Zhi
Published: March 2010

This paper gives research on Neural Network for AM Automatic Logistics information System’s Modeling, Simulation and algorithm, contrasted to traditional methods of forecast. In order to raise the design efficiency and get the most excellent design effect, this paper combined Ant Colony Optimization (ACO) algorithm and neural networks, which based on ACO algorithm and the implementing framework of ACO. It gives the basic theory and steps; which proved research on Neural Network for AM Automatic Logistics information-System has good ability of non-linear function’s approach and latent feedback’s dynamic data processing, study online time short, parameter convergence swift, self-adapt ability good, can study and adapt to severity uncertainly dynamic system’s tract, forecast precision is high.
Simulation Based Model Experimentation with Minimum Solving Strategy
Authors: Jiang Zhan Si , Jiang Hui , Wu Yi Zhong , Xiang Jia Wei
Published: March 2010

The process of model experimentation can be regarded as repeatedly evaluating simulation models by varying parameters of the model. At present, the solvers of simulation tools usually need to calculate all the coupling blocks during every simulating run after parameters varying. In order to greatly improve the efficiency of the process of repetitious simulation, a new method named minimum solving strategy is proposed and implemented. By this method, carrying out model experimentation with different parameters values only need to calculate the solving sequence influenced by parameters altering.
Effect of Process Routing on Machining Deformation for Multi-Frame Double Sided Monolithic Components
Authors: Tang Zhi Tao , Liu Zhan Qiang , Xu Li Qiang
Published: March 2010

When machining aerospace monolithic components, a severe deformation can be observed due to the release and redistribution of the original residual stresses, together with the action of cutting loads and clamping force. In this paper, a finite element model predicting machining deformation was developed considering the above mentioned multi-factors coupling effects. Based on the model, the effect of process routing on machining deformation for multi-frame double sided monolithic components was studied. To validate the FE model, true frame components were machined and deformations were measured on a Coordinate Measuring Machine. The result revealed that the prediction model is credible. At last the paper puts forwards optimal process routing based on minimizing the machining deformation.
Effect of Diesel Nozzle Geometry on Internal Cavitating Flow
Authors: He Zhi Xia , Mu Qing Mu , Wang Qian , Yuan Jian Ping
Published: March 2010

The presence of cavitation and turbulence in a diesel injector nozzle has significant effect on the subsequent spray characteristics. However, the mechanism of the cavitating flow and its effect on the subsequent spray is unclear. The initiation, development and collapse of the cavity are strongly influenced not only by the injection pressure and back pressure but also by the nozzle geometry. The numerical simulation of cavitating flow in nozzle holes of a vertical multi-hole injector with mixture multi-phase cavitating flow model was carried out. The effects of sac geometry, hole entrance curvature radius and hole inclination angle on the cavitating flow in nozzle holes were investigated. It is finally concluded that the performance of IMPROVED nozzle is better than that of STD nozzle and VCO nozzle and small inlet turning angle of the orifice can enhance the atomization of the spray.
Influence Factors on Finishing Temperature of Plate Rolling
Authors: Zhao Zhong , Hu Xian Lei , Wang Guo Dong
Published: March 2010

Based on the character of plate rolling, the temperature model was developed by considering the influence of radiation, convection, water descaling, and roll conductivity and deformation energy. The factors affect the finishing temperature of the plate were analyzed, including the holding time during control rolling, rolling speed, slab temperature and pass number. Holding time, rolling speed and slab temperature have significant influence on finishing temperature, and pass number has great influence on finishing temperature of thick plate, but has little on finishing temperature of media plate.
Formation Mechanism and Simulation of Oxide Film in Electrodeless ELID Grinding
Authors: Tang Kun , Yin Shao Hui , Fan Yu Feng , Zhu Yong Jian , Zeng Xian Liang
Published: March 2010

This paper reports a study on oxide film formation mechanism in electrodeless ELID grinding. The formation mechanism of oxide film was analyzed based on electrochemical principles, its formation model was built and the growth process was also simulated. The simulation results showed that the oxide film thickness h and its growth rate g are nonlinear functions of time t, voltage and duty cycle are important factors which take effect on g and h, and the electrodeless ELID grinding is a process of weak electrolysis and suitable to use micro wheel.
Crawler Cranes Modeling Method Based on OGRE
Authors: Wu Di , Li Xiao Yan , Gao Shun De , Lin Yuan Shan , Wang Xin
Published: March 2010

According to the crawler crane’s structure and the scene management principle of OGRE (Object-Oriented Graphics Rendering Engine), this paper presents a new 3D parameterized modeling method of crawler cranes. By integrating the interactive modeling using 3DSMAX and the geometrical graphics modeling, the new method can solve the problem about rendering speed, vivid and parameterized models and how to obtain the position of key points. A case is described in order to demonstrate the use of the developed method and to illustrate its reliability.
Numerical Simulation of Double Rollers Clamping Spinning Process for Flanging
Authors: Zhao Sheng Dun , Fan S.Q. , Zhang Q. , Wang C.H.
Published: March 2010

Double rollers clamping spinning (DRCS) is a new process to form thin-walled rotary shell parts with complex flange, which adopts two rollers to clamp the workpiece in the forming. Using FE simulation code ABAQUS/Explicit, the 3D simulation model of DRCS process for flanging is established, and the whole DRCS process and material deformation have been simulated. Distribution of equivalent stress, equivalent strain and wall thickness of flange in the DRCS process are obtained. And then, the effects of roller feed rate and flange length on the formed flange part are studied. Results show that equivalent stress, equivalent strain and reduction in wall thickness increase with the decrease of roller feed rate, while increase with the increase of flange length. The results obtained in this paper can provide the references to determine and optimize the new spinning process parameters.
On the Control System for Blank-Holder Force in Deep Drawing Based on Self-Tuning Fuzzy-PID Controller
Authors: Cao Chun Ping , Sun Yu
Published: March 2010

Blank-holder Force (BHF) control technology is an important guarantee for the quality of parts forming. Taking YJ28E—1000/1600Q hydraulic press as object, a hydraulic fuzzy control model based on self-tuning fuzzy-PID is built to deal with the undesirable dynamic response and the low steady-state precision of the hydraulic control system. The look-up table for optimal control parameters is generated from MATLAB Toolbox. A simulation study of the system shows that the dynamic response and steady-state precision is improved greatly by adopting this kind of self-adaptive fuzzy-PID controller.
Blade Diamond Disk for Conditioning CMP Polishing Pad
Authors: Tsai Ming Yi
Published: March 2010

A diamond conditioner or dresser is needed to regenerate the asperity structure of the pad and recover its designed ability in chemical mechanical polishing (CMP) process. In this paper a new design of diamond conditioner is made by shaping a sintered matrix of polycrystalline diamond (PCD) to form teethed blades. These blades are arranged and embedded in epoxy resin to make a designed penetration angle, called the blade diamond disk. The dressing characteristics of pad surface textures are studied by comparison with conventional diamond conditioner. It is found that the height variation of the diamond tip of blade diamond disk is significantly smaller than the conventional diamond disk. The dressing rate of blade diamond disk is lower than that of the conventional diamond disk, and hence the pad life is prolonged. As a result, reduction of the cost CMP is expected. In addition the pad surface roughness Ra of about 3.79μm is less than Ra of about 4.15μm obtained after dressing using a conventional diamond disk.
A Finite Element Analysis for the Characteristics of Cutting Parameters in 3D Oblique Milling Process
Authors: Qin Guo Hua , Xin S.Q. , Lu Dong , Rong Yi Ming
Published: March 2010

In the field of aeronautical and astronautical manufacturing, milling is a basic machining process by which a surface is generated by progressive chip removal. Therefore, this paper reports a complete procedure of the finite element model for the 3D oblique milling process using the commercial software package ABAQUS. Effect of various parameters on cutting forces is mainly discussed. The model correctly exhibits the observed transition from small to large force with increasing cutting speed and cutting depth.
Simulation and Experimental Investigation for the End Milling Process of 7075-T7451 Aluminum Alloy
Authors: Wang Cong Kang , Qin Guo Hua , Lu Dong , Xin S.Q.
Published: March 2010

During the milling operation, milling forces are the main factor to cause the machining deformation of the workpiece. The flow stress of Al 7075-T7451 was first described as a function of strain, stain rate and temperature in order to obtain the true behavior in machining process. Second, a finite element method of milling process of Al 7075-T7451 was developed to obtain milling force simulations. Finally, simulated results are compared with experimental data and are shown to be in good agreement with each other.
The Algorithm of Acoustic Location for Boiler Tube Leakage
Authors: Tong Peng , An Lian Suo , Jiang Gen Shan , Wang Yu Qing
Published: March 2010

The time delay estimation algorithm based on generalized cross correlation, can suppress the noise power effectively. More accurate result can be gotten by this method of time delay estimation. It is proved by simulation and experimentation that the estimated value of time delay given by generalized cross correlation method is more accurate than which is given by basic correlation method when the signal and noise ratio is stationary, thus the location result based on the time delay is more accurate.
Optimization of Surface Roughness Based on Multi-Linear Regression Model and Genetic Algorithm
Authors: Pan Yong Zhi , Zhao Jun , Fu Xiu Li , Ai Xing
Published: March 2010

During the high-speed milling operations of 7050-T7451 aluminum alloy using solid carbide end mills, helical angle, axial and radial depth-of-cut have significant effects on the milling uniformity. A surface roughness predictive model of work-piece was developed by using a full-factorial experimental design and multi-linear regression technology. Genetic algorithm was utilized to optimize the helical angle and cutting parameters by means of a series of operations of selection, crossover and mutation based on genetics. The result shows that it is possible to select optimum axial depth-of-cut, radial depth-of-cut and helical angle for obtaining minimum cutting force and reasonably good metal removal rate.
A New Ultraprecision Machining Method with Softness Abrasive Flow Based on Discrete Phase Model
Authors: Ji Shi Ming , Xiao Feng Qing , Tan Da Peng
Published: March 2010

Considering the demand of precision in mould structural surface polishing method, a new method based on soft abrasive flow machining(SAFM) was proposed, which was supposed to achieve polydirectional and multi-angle cutting acting on the surface of the workpiece by utilizing the irregular motion of both wear particles and the media in turbulence flow. Thus as the monodirectional marks on the machined surfaces was eliminated, the disadvantage in machining precision in conventional abrasive flow machining(AFM) method would be overcome. According to the particle distribution characteristics of SAFM, a two-phase dynamic model of abrasive flow oriented to SAFM combined with Discrete Phase Model(DPM) was built to analog simulation with the software Fluent. Sequently the mechanism of ultraprecision machining towards mould structural surface was analyzed briefly. Simulation results show that the abrasive efficiency along the flow passage can be influenced by the development of turbulence and the distribution of dispersed phase. Thus there a specific region can be obtained in the passage in which the abrasive efficiency is relatively stable.
Research on Precision Forming Technology of Car Steering Knuckle
Authors: Zhao De Ying , Zhang Lian Dong , Sun Hui Xue , Sun Li Na
Published: March 2010

Steering knuckle is the key part of vehicle steering system, and its mechanical properties and surface qualities are very strict. The current production technologies of branch-like steering knuckle are obsolete, which become the restriction of increasing productivity and improving the quality. Aiming at Jetta steering knuckle, the technology of two forging steps in one heat is presented. This technology is mainly composed of a closed die extrusion with the extrusion belt and open finish-forging. Experimental researches and numerical analysis show that the new technology is feasible and the mechanical property of the forging piece can be improved.
Finite Element Analysis on the Roll Milling Process of Twisted Oblate Tube
Authors: Yang Sheng , Zhang Li , Xu Hong , Zhao Li Wei
Published: March 2010

The roll milling process for manufacturing a twisted oblate tube was presented and applied in the forming of twisted oblate copper tube successfully. A finite element simulation of the roll milling process for forming a twisted oblate 1010 steel tube was implemented on the basis of the elastic-plastic explicit dynamic finite element method under the ANSYS/LS-DYNA environment. The simulation accuracy was verified by comparing the forming force from simulation with the experimental results. The forming effect, change curve of forming force, tube stress distribution and influences of forming parameters on forming force were investigated. The simulation results can be guidance to the manufacturing process improvement and manufacturing equipment design of the twisted oblate steel tube.
Mechanical Analysis on the Inner Surface Crack of Modified 9Cr-1Mo Seamless Steel Tubes Rolled by Mandrel Mill
Authors: Li Sheng Zhi , Xu Jie , Yin Yuan De , Su Hui Chao
Published: March 2010

The inner surface crack (ISC) defect easily occurs in seamless modified 9Cr-1Mo steel tubes rolled by the mandrel mill with high production efficiency. The reason for the formation of the ISC lies in both the properties of deformed material and rolling conditions. With the aid of commercial FE code MSC.SuperForm, the rolling process of modified 9Cr-1Mo seamless steel tube produced by the Mandrel Mill of Bao Steel in China was simulated, focusing on mechanical analysis of deformed metal. It was found from the simulation that the metal on the inner surface of the tube, in the position of 0 or 90 of the roll pass, experiences strong tensile stresses, especially the circumferential stress, which is closely related .to the strain behavior governed by the two-high pass caliber of the mandrel mill. Therefore an optimal design of the roll pass can be realized to decrease the tensile stress so as to relax the tendency to the ISC, which has been confirmed by the tests in Steel Tube & Pipe Company of Bao Steel.
Finite Element Simulation of the Effects of Mould Angle on the Equal Channel Angular Pressing for Al-Zn-Mg-Cu Alloy
Authors: Cai Gang Yi , Liu Xiao Xia
Published: March 2010

Finite element simulation of the effects of mould angle on the equal channel angular pressing (ECAP) for Al-Zn-Mg-Cu aluminum alloy was investigated by using DEFORM-3D program. The results show that the work load ascended with the increasing of the mould angle and was divided into five stages including rapid increasing stage, steady stage, rapid increasing stage, steady stage and rapid drop stage. When the angle decreased from 150° to 90°, the maximum load increased by 2.87 times and the energy consuming increased by 2.36 times. In addition, with the decreasing of mould angle, the average effective strain increased after single extrusion, while the degree of effective strain uniformity of the sample decreased. There were greater strain grads between inner and surface part. As mentioned above, large angle mould should be adopted on ECAP for Al-Zn-Mg-Cu aluminum alloy in order to ensure extrusion smoothly and attain homogeneous fine grain.
Research on the Temperature Properties of Plate during the Laminar Cooling Process
Authors: Wang Jun , Wang Bing Xing , Huo Wen Feng , Chen Xiao Lin
Published: March 2010

For the purpose of realizing high-precision control of temperature profile during laminar cooling process after hot rolling, the characters of temperature variation inside hot plate are analyzed with the finite element method. The temperature properties of the plate, including the temperature drop, the temperature difference in the plate thickness direction, the cooling rate, and the red-back process, is researched under different cooling conditions. The law of the temperature properties variation with the plate thickness and the flow rate is obtained.
The Forming Scheme of a Silencer Cover in Progressive Die
Authors: Liu Ming Jun , Liu Bai , Tang Fei
Published: March 2010

The drawing scheme of a silencer cover in the progressive die was studied. This cover was formerly processed by several single punching dies and now was produced by a progressive die. The drawing scheme was hard to determine. Therefore, the explicit dynamic software DYNAFORM was applied to make simulations about the drawing process. According to comparisons between the simulation and experiment results, the optimized drawing scheme, blank layout, blank size, binding force and some other process parameters were determined. The defects were eliminated after the proper drawbead was set. Experiments showed that numerical simulation provided an efficient way for the optimization of the forming scheme in the progressive die production.
Transmission Ratio Analysis and Controllable Tooth Profile Modeling for the Nutation Drive with Double Circular-Arc External and Internal Spiral Bevel Gears
Authors: Lin Zheng , Yao Li Gang , Huang Shu Juan
Published: March 2010

This paper proposes an approach for calculating the transmission ratio of nutation drive based on the working principle of the nutation movements. Then, the analysis of the influences for the nutation angle on the transmission ratio is carried out. The controllable tooth profile modelling for external and internal spiral bevel gears with double circular-arc is proposed. Based on the proposed tooth profile modeling, the three dimensional modeling and virtual assembly of the nutation drive have been further completed. Finally, the kinematical simulation is preceded in the simulating system and the comparative results have been accomplished between the simulation results and the theoretical ones of the transmission ratio.
Application of Finite Difference Method in Billet Gradient Cooling Employed in Isothermal Extrusion
Authors: Li Jing Yuan , Yang Guang Tu , Lin Chun Kun , Meng Fan Wang
Published: March 2010

In the present work, a finite difference model (FDM) is built to predict the transient temperature field of the aluminum billet in the gradient cooling process. The billet is divided in 5 segments, each of which is corresponding with one water cooling ring, and all of which are water-cooled for different times respectively in order to obtain the target temperature gradient. On the following air cooling stage, the temperature of the outer layers, especially the surface, rises first, then falls slowly. With the rising of the surface temperature, the temperature deviation from the center to the surface is narrowed intensively. In comparison with the commercial finite element method (FEM) software, Deform 3D, the FDM model gets nearly the same prediction results as FEM simulation does.
A Mathematical Model for Predicting Residual Stresses in Pre-Stretched Aluminum Alloy Plate
Authors: Zhang Shu Yuan , Wu Yun Xin
Published: March 2010

A mathematical model has been developed to predict the residual stresses level in pre-stretched aluminum alloy plate. This is based on force balances of the residual stress, theory of plastoelasticity and a new conception of free length. The model is relatively simple because only rolling direction residual stress is taken into account, but provides a clear illustration of stress relief mechanism in stretching process. With this model, residual stress distributions of stretched beam can be determined directly by knowing the specimen dimensions, material properties and the original stress. The model offers an useful tool to show the effect of varying tension ratio on the final residual stress level, thus makes it possible to predict stress relief and control residual stresses. An example of using the model is presented by applying published data while showing mechanism of stress relief during stretching. Analysis indicates that it is stretch-caused convergence of the free lengths of strips in beam that lead to reduction in the residual stresses.
Plastic Deformation Characteristics Analysis in Rotary-Draw Bending Process of Thin-Walled Rectangular Tube
Authors: Zhao Gang Yao , Liu Yu Li , Yang He
Published: March 2010

The rotary-draw bending process of thin-walled rectangular tube is a complex process with large deformation, large displacement and finite strain which makes the defects, such as wrinkling, distortion and crack be easily produced. To study the complex plastic deformation characteristics, a 3D-FE model for the process was built and validated by experiments. Then simulation and analysis of complex plastic deformation characteristics of the process were carried out. The results show that the distributions of stress and strain are symmetric, and its peak values appear in the edges of tube. With the increase of bending angle, the equivalent stress and equivalent strain initially increase and then reach at a stable value, whereas the fluctuant phenomenon of tangent stress is produced. The moving of the neutral plane of stress can be ignored; however, the moving of neutral plane of strain is more obviously.
Modeling of Mircrostructure Evolution in Directional Solidification of Ni-Based Superalloy Turbine Blade
Authors: Pan Dong , Xu Qing Yan , Liu Bai Cheng
Published: March 2010

Directional solidified turbine blades of Ni-based superalloy are widely used as key parts of the gas turbine engines. The mechanical properties of the blade are greatly influenced by the final microstructure. In this paper, a mathematic model was proposed for the three dimensional simulation of microstructure evolution in directional solidification. Based on the thermo model of heat transfer, the grain growth within the blade and the microstructure morphology were simulated via a Cellular Automaton method. Validation experiments were carried out. The simulated cooling curves and microstructures corresponded well with the experimental results.
Stability Margin Sensitivity Analysis of a Multi-Rotor System Geared by Spiral Bevel Gear Pairs
Authors: Fan Ye Sen , Wang San Min , Yang Zhen
Published: March 2010

To study the stability margin sensitivity to the parameters of the geared rotor system is prerequisite to carry on structure optimization design and vibration control. The global dynamic equations of the geared two rotor system are set up through the coupled matrix of the spiral bevel gear pairs, and the stability margin is obtained by analyzing the global dynamic equations. To enhance the damping of the bearings and to enhance the module and mesh damping of the gear pairs can improve the stability margin of the geared rotor system. The method for the stability margin sensitivity analysis of the geared multi-rotor system is feasible. The conclusions from the numerical example are useful to improve the stability margin of the geared multi-rotor systems.
The Influence of Interfacial Thermal Contact Conductance on Resistance Spot Weld Nugget Formation
Authors: Li Yong Bing , Lai Xin Min , Chen Guan Long
Published: March 2010

Resistance spot welding process is strongly related to interfacial contact behaviors. The effects of thermal contact is rarely investigated so far and generally ignored in numerical models. In this work, a parametric FE model, which considers the variation of the surface roughness of the electrodes and workpieces, has been developed to investigate the effects of thermal contact on weld nugget formation. With the parametric model, four cases, e.g. ideal smooth surface, minimal roughness surface and maximum roughness surface for steel sheets and electrodes of as-received condition, and highly rough electrode surface, are investigated. Researches show that when the surface roughness of the electrodes exceeds some limit, the thermal contact conductance will substantially affect the weld nugget formation, therefore, must be considered in numerical models to precisely predict welding process.
A New Miniaturized CNC Machine Tool
Authors: Zhang Lin , Liao Wen He , Yang Hui
Published: March 2010

A miniaturized CNC (Computerized Numerical Control) milling machining equipment was mentioned for micro milling processing. The equipment has a highest spindle speed of 90000rpm and the positioning accuracy of submicron. Furthermore, it described the design of CNC servo system of precision stage driven by linear motor. The servo experiments results verified the excellent static and dynamic performance of the system. The machining tests included a plane with a surface roughness of 215nm using a end milling cutter of Φ0.2μm, micro straight slots with a dimension error range of 1-2μm using a ball-end cutter of Φ0.2μm and some complex structures. The analysis results of these tests show that the system is able to fulfill the micro milling machining of micro components.
The Effect of Bending Rigidity on Measuring the Adhesion Work of Membrane
Authors: Wang Shi Ji , Li Xian
Published: March 2010

A theoretical model is developed to examine the effect of bending rigidity on measuring the adhesion work between a flat punch and a flexible membrane by pull-off test. The validity of this model is certified by the theoretical analysis. It can be used in the future experiments to analyze the experimental data when the bending rigidity of the membrane cannot be ignored. From our quantitative analysis, the effect is remarkable and sensitive to the bending rigidity. The effect of bending rigidity should not be neglected unless the membrane is very soft or the membrane is very thin. The elastic modulus of membrane should be less than 1.6MPa when the thickness of the membrane is less than 10μm. Moreover, it is obviously that the thickness plays a key role in the bending rigidity.