bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Interfacial Reaction on Joint Strength of Semiconductor Metallization and Sn-3Ag-0.5Cu Solder Ball
Authors: Yorita Chiko , Kobayashi Tatsuya , Shohji Ikuo
Published: January 2011

Semiconductor packages that use metallization and lead-free solders are increasingly being used in electronic products. In this study, interface reactions and joint-strength reliability were investigated for Sn-3W%Ag-0.5W%Cu solder ball joints joined to Cr/Cu and Cr/Ni-40W% metallization layers that were heat treated at 260°C. The strength of the joint with the Cr/Cu metallization layer decreased as the duration of the heat treatment increased. Sn and Cr interface reactive layers were generated after the loss of Cu in the Cr/Cu metallization layer, but the connection was maintained. By contrast, the connection of the joint to the Cr/Ni-40W metallization layer was relatively stable under the heat treatment conditions investigated.
Implementing an Open-Architecture Controller for a Tension-Compression Fatigue Test Machine
Authors: Imani B. Moetakef , Ghandehariun A. , Ghorashi H.
Published: January 2011

In this research, an enhanced force control unit is proposed and implemented on a hydraulic tension-compression fatigue test machine. In this regard, different sensory data, such as force, hydraulic pressure, displacement and oil temperature is acquired and conditioned for controlling different subsystems of the machine. First, the transfer function of the system is identified. Then, a control strategy for applying cyclic force on the specimen with prescribed amplitude and frequency is proposed. The performance of the whole system is examined for the working range of the excitation frequency. In addition, the developed open-architecture controller can be used for testing the real parts found in various branches of industry. It can also be upgraded to be used on a universal fatigue test machine. It is shown that the designed controller can improve the performance of the machine significantly.
Shrinkage Cracking of High Performance Concrete Mixed with Steel Slag Admixture
Authors: Li Yun Feng , Guo Hua Xun , Wang Ling Ling
Published: January 2011

Cracking due to the restrained shrinkage stress has been frequently observed at early age in concrete structures. Early-age deterioration of concrete due to cracking and higher maintenance cost for poor durability cause serious troubles to concrete structures. Steel slag includes a certain scale mineral such as C2S and C3S, and can be applied in cement and concrete as mineral admixtures. Two tests are outlined to quantify the behaviour of concrete under restrained shrinkage using plate and ring specimens. The results show that mineral admixtures can be used to reduce cracking in concrete. The risk of cracking can be estimated for steel slag concrete, so that it will improve the durability of concrete structures.
Flexibility Analysis of the Welded Metal Bellows of Mechanical Seal
Authors: Gheni Mamtimin , Musha Halida , Yusup Nijiat , Baki Kurban
Published: January 2011

In this study, the stiffness and the flexibility of welded metal bellows of mechanical seal is studied numerically by changing the number of bellows membrane and the loading condition. The relationship between the number of membrane and the displacement, the stress and the flexibility are analyzed. For further improved the axial displacement, overall stiffness and the flexibility of the welded metal bellows membrane, the finite element analysis are conducted. The numerical results show that the maximum stress keeps constant value with increasing the number of bellows membrane under the same loading condition. The relationship between number of bellows membrane and stiffness as will as the flexibility are obtained. It is shown, stiffness is decreased and flexibility is increased with increasing of the number of the bellows membrane.
Non-Destructive Techniques (NDT) in Composite Materials
Authors: Suriani M.J. , Ali Aidy , Sapuan S.M. , Khalina Abdan
Published: January 2011

The aim of this review is to gain the informations on applications and approaches that are presently available for non-destructive techniques (NDT) in composite materials. This review also will enhanced the knowledge in the NDT fields with available studies theories and research works done currently. Thus, it has been concluded the research that have been done in the past for military purpose but nowadays (NDT) technique is widely used in other various applications including composite materials, fire safety, land determine, food safety and quality and also famously practice in medical used.
Analysis of Coconut Carbon Fibers for Gas Diffusion Layer Material
Authors: Indayaningsih Nanik , Priadi Dedi , Zulfia Anne , Suprapedi
Published: January 2011

The main compound of natural fibers is a hydrocarbon. The heating of hydrocarbon in inert gas produces charcoal or carbon. Carbon materials are widely used for several purposes depending on the physical and electric properties, for example for hydrogen storage, conductive or reinforced plastics, catalyst supports, batteries and fuel cells. The main raw material of Gas diffusion Layer (GDL) of the Proton Exchange Membrane Fuel Cell (PEMFC) is a carbon. The properties of GDL are porous and electron-conductive material, because of the function of GDL is to distribute the gas as fuel and electricity conductors. This study aims to analyze the carbon fibers made from coconut fibers for the application of GDL materials. The carbon fiber was made using pyrolysis process in the inert gas (nitrogen) at a certain temperature according to the analysis of Differential Thermal Analysis (DTA) 3000C, 4000C, 5000C, 6000C, and 9000C. The crystalstructure, carbon content, powder density and morphology of carbon fibers were observed using X-Ray Diffraction (XRD), fixed carbon according to ASTM D 1762-64, Archimedes method (BS 19202 Part 1A), and Scanning Electron Microscope (SEM), respectively. The results showed that the structure of carbon was amorphous, and content of 51% ̶ 71%, powder density of 0.42g/cm3 ̶ 0.71g/cm3. The morphology having many parallel hollows like a tube that are close to each other with diameters of 2m ̶ 10m, and in the wall of tube there are some porous with sizes around 1m. According to this analysis, the coconut carbon fiber enables to be applied as candidate for a basic material of GDL.
Influence of Strength Level of Steels on Fatigue Strength and Fracture Morphology of Spot Welded Joints
Authors: Tohgo Keiichiro , Ohguma Tomoya , Shimamura Yoshinobu , Ojima Yoshifumi
Published: January 2011

In this paper, fatigue tests and finite element analyses are carried out on spot welded joints of mild steel (270MPa class) and ultra-high strength steel (980MPa class) in order to investigate the influence of strength level of base steels on fatigue strength and fracture morphology of spot welded joints. From the fatigue tests the following results are obtained: (1) Fatigue limit of spot welded joints is almost the same in both steels. (2) Fatigue fracture morphology of spot welded joints depends on the load level in the ultra-high strength steel, but not in the mild steel. From discussion based on the finite element analyses the following results are obtained: (3) The fatigue limit of spot welded joints can be predicted by stress intensity factors for a nugget edge, fracture criterion for a mixed mode crack and threshold value for fatigue crack growth in base steel. (4) Plastic deformation around a nugget in spot welded joints strongly affects the fatigue fracture morphology.
Effects of Different Die and Epoxy Thickness to the QFN Package
Authors: Abdullah Huda , Shaarani Muhd Fauzi Aminuddin Shazi
Published: January 2011

Quad Flat No-Lead or QFN is able to provide lighter, thinner and higher performance packaging requirement with its exposed pad and leads at the package bottom for better heat dissipation. However, QFN packages possess certain weaknesses. QFN package failures are related to crack and delaminating, such as die cracking, moulding compound and solder mask interfacial delaminating. From previous projects, the epoxy thickness and die thickness plays an important role in reducing failures in QFN package. The objective of this project is to observe the effects of die and epoxy thickness. The effects on QFN are measured in the die and lead frame part. Stress towards the die is also measured: including thermal, first principle and Von Misses stress. The structural optimization is based on the Finite Element Analysis (FEA). By using ANSYS 10.0, six models were constructed, where three models were built to analyse in thickness of epoxy, and another three to study the effects on die thickness. The effect was measured by the value stress (first principle stress and Von Misses stress) and thermal strain effect, which will lead to a result of how the dimensions of the packaging will give a better tolerance towards stress.
Durability of R/C Structures under Mechanical and Environmental Action
Authors: Giordano Luca , Mancini Giuseppe , Tondolo Francesco
Published: January 2011

In the present work, an experimental campaign on reinforced concrete elements subjected to simultaneous loading and degradation due to corrosion is presented. The specimens are loaded in tension and the cycling action is designed in order to simulate in terms of stress peak and stress variation, the effect of the passage of vehicles under fatigue design situations. The environmental action is simulated by means of corrosion induced with an electrochemical process; the corrosion rate is chosen in order to obtain about 27 years of equivalent carbonation attack within 25 days of test. In the mean time, 6.5·106 loading cycles are achieved. In addition to those standard tests, also other static tests were conducted in order to have a comprehensive analysis of the deterioration processes. Evolution of transversal crack due to loading and of longitudinal cracks due to corrosion is monitored. They can be related to the internal bond condition between steel and concrete. Results highlight the differences in terms of corroded and uncorroded specimens, static and cycling test and also different loading amplitude. Finally it can be observed as the growing of the damage is significantly different when a cycling action, combined with a chemical attack, is present.
Effect of Aging Treatment on Microstructure and Mechanical Properties of Al-Si Matrix Alloy Reinforced with High Purity Aluminum Nitride (AlN)
Authors: Wahab Mahamad Noor , Ghazali Mariyam Jameelah , Daud Abdul Razak
Published: January 2011

Microstructure and mechanical properties of heat treated Al-Si alloy containing up to 10 wt% aluminum nitride (AlN) particles were investigate. In this work high purity AlN powder with different weight percentage of 0, 5, 7 and 10 were calculated as reinforced material to the metal matrix composites. The Al-Si matrix was prepared by a bottom pour stir casting technique. Heat treatment was performed by soaking and followed by an aged treatment. It was found that the AlN particles were scattered randomly distributed in the matrix composite. Ageing induced Si grain transformation into to spheroid shapes while Al dendrites tend to become finer. Ultimate tensile strength (UTS) had improved drastically from to 125MPa to 306MPa for un-aged Al-Si alloy and aged AlN 7 wt%. Fracture morphologies showed a pronounced feature with small dimples, tear ridges and micro neck particularly in the aged samples leading to a higher tensile value and increase in ductility. The presence of AlN particles in the alloys had improved the tensile strength by slowing down the plastic deformation during tensile test.
Influences of Crack Face Bridging Stress and Microstructure on Fracture Toughness of Toughened Alumina Ceramics
Authors: Sakaida Yoshihisa , Yoshida Hajime , Mori Shotaro
Published: January 2011

Three types of polycrystalline alumina, one pressureless and two hot press sintered Al2O3, were used to examine the effects of the characteristics of microstructure and crack face bridging on fracture toughness. The crack opening displacements and microstructures along the pop-in crack of single edge precracked beam (SEPB) specimens were observed in situ at a constant applied stress intensity factor by scanning electron microscopy (SEM). The bridging stress distribution could be determined from the measured crack opening displacement by three-dimensional finite element analysis, and then the stress intensity factor and stress shielding effect at the crack tip could also be determined. Intergranular microcracks of toughened Al2O3 were deflected by a complicated microstructure, and crack closure due to bridging grains was observed near the crack tip. Bridging stress of Al2O3 was compressive perpendicular to the crack face and was distributed behind the crack tip. The maximum bridging stress of two hot press sintered Al2O3 was about twice as large as that of pressureless sintered Al2O3. The fracture toughness of hot press sintered Al2O3 was, therefore, higher than that of pressureless sintered Al2O3, because the total amount of bridging stress and stress shielding effect increased with increasing magnitude of microcrack deflection and the number of interlocking grains.
Study of Inner Micro Cracks on Rolling Contact Fatigue of Bearing Steels Using Ultrasonic Nano-Crystalline Surface Modification
Authors: Lee Chang Soon , Cho In Shik , Pyoun Young Shik , Park In Gyu
Published: January 2011

The purpose of this study is to analyze the effect of ultrasonic nano-crystalline surface modification (UNSM) treatment on rolling contact fatigue (RCF) characteristics of bearing steels. It was found that severe plastic deformation occurred at surface by over 100 µm after UNSM treatment. The micro surface hardness was increased by 18%, and the measured compressive residual stress was as high as -700~-900MPa. The polymet RCF-2 roller type RCF test showed over 2 times longer fatigue lifetime after UNSM treatment under Hertzian contact stress of 425.2kg/mm2 and 8,000 rpm. And SEM study showed a spalling phenomenon at the samples which went through the RCF test after UNSM treatment. Samples before UNSM treatment produced surface initiated spalls and multi shear lips by progressive spalling at the end along the rolling direction, but sub-surface initiated spalls were formed without multi shear lips after UNSM treatment. The spalling occurred at once, and the size and depth of spalls were larger than those before UNSM treatment. And micro cracks were found to form within the spallings after UNSM treatment, and stress distribution at the maximum Herzian shear stress through these micro cracks is thought to improve the fatigue lifetime of bearing materials.
Study on Numerical Simulation Method of Periodic Symmetric Struts Support Coupling with Heat Flow and Solid
Authors: Gheni Mamtimin , Li Zhen Shi , Cheng Wei , Liu Wei Bing , Yu Lie
Published: January 2011

In this paper, the fluid solid coupling method is used and the FE (Finite Element) analysis is conducted for the PSSS (Periodic Symmetric Struts Support) of the large scale GT(Gas Turbine), and the overall thermal stress and thermal deformation are obtained. From the structure feature of the gas turbine, the initial boundary conditions of the high-temperature gas flow field and thermal deformation are analyzed at first. Then the coupling relationship between fluid and solid two phases is expressed mathematically, and the thermal conductivity is considered for calculation of heat transfer process, and the overall temperature field is obtained. Finally the thermal boundary condition of PSSS is defined and the structural FE analysis is conducted. At the same time, the thermal stress field and thermal deformation field are discussed for overall PSSS structure.
Abrasion and Erosion-Corrosion Behavior of Al-Mn Alloy Matrix Composites Reinforced with Al2O3 Particulates
Authors: Li Xin Mei , Liu Bing , Sun Wen Lei , Jin A Fang , Liu Xiang
Published: January 2011

Al-2%Mn alloy matrix composites reinforced with Al2O3 particulates was fabricated by stirring cast, and the composites was characterized and analyzed by using a variety of analytical techniques, such as XRD, SEM, EDS, Brinell hardness tester, ring-on-block tribometer, and erosion-corrosion tester. The results show that the composites in as cast condition is mainly composed of Al,  -Al2O3, MnAl6 and Al11Mn4 phase, and the Al2O3 particles are dispersed uniformly in the Al matrix. Compared with the base aluminium and the Al-2%Mn alloy, the HB hardness of the composites is increased significantly, and the wear loss is far less under the SO4•Cl- Na•Ca• Mg corrosive alkalescent aqueous solution lubricated condition. The erosive-corrosive wear rates of the composites are lower than those of the Al-2%Mn alloy irrespective of the rotational speed or the size of grinding particles. The Al2O3 particulates reinforced Al-2%Mn alloy matrix composites possesses a good wear-resistance and erosion-corrosion resistance due to its higher hardness.
Synchronization Based Control for Walking Assist Suit-Evaluation on Synchronization and Assist Effect
Authors: Zhang Xia , Hashimoto Minoru
Published: January 2011

We propose a framework of realizing natural assist behavior with a walking assist suit inspired by human interaction. We look at the human interaction as a behavior of synchronization action, which is a common phenomenon in walking assist between human. To achieve this human-like walking assist, synchronization based control is adopted and applied to a walking assist suit. We use neural oscillators to entrain and synchronize the assist suit’s motion with that of human user. To determine the validity and feasibility, walking experiments have conducted with a 4-DOF walking assist suit. The results showed the validity of using synchronization based control for walking assist suit.
Real-Time Detection System of Soil Moisture Based on GPRS
Authors: Zhang Rong Biao , Guo Jing Jing , Wang Qi , Zhang Lei , Wang Xian Lin
Published: January 2011

Real-time monitoring of soil moisture is essential for agricultural production. In this paper, an improved system is designed based on GPRS technology for real-time detecting soil moisture, a salinity calibration model is established based on Least Squares Support Vector Machines on MatLAB (LS-SVMlab) for improving detection precision. The transmission of soil moisture information is the key technology of the system, by software and hardware design we have solved the problems of data congestion, off-line, and moving the monitoring terminal at any time, which still restrict the application of GPRS in soil moisture detection. Field tests show that the system can realize seamless connection between the collection nodes and remote host, and acquire soil moisture accurately. Simultaneously, the time of re-networking has been shortened greatly.
An Efficient Slicing Algorithm for Asynchronous Linear Hotwire Cutting System of Expandable Polystyrene Foam
Authors: Hao Jing Bin , Fang Liang , Wang Jing Ya
Published: January 2011

The asynchronous linear hotwire cutting (ALHC) system of expandable polystyrene (EPS) foam is a new rapid prototyping (RP) technology, which uses the asynchronous linear hotwire cutter and EPS foam to fabricate the part. The efficiency and capacity of ALHC system depends significantly on the pre-process of STL model. This paper presents an original algorithm for adaptively decomposing a STL model into a set of variable slices, which can be efficiently fabricated by ALHC system. A large complex model is first partitioned into several smaller and simpler sub-models by using the curvature-based partitioning. Then, these sub-models are sliced into layers with different thickness based on feature facets. Several experimental results demonstrate the reliability and efficiency of the slicing algorithm.
Mechanical Properties Evaluation of Nanofiber/Webs
Authors: Enomoto Yuji , Kim Ick Soo
Published: January 2011

Recently ultrafine fibers of nanometer size and their fabrics are growingly interested not only in textile industry but also in non-textile industry, as they have excellent properties of lightness, high strength, comfort, function and etc as compared to those of conventional fibers. Evaluation of the mechanical properties is, then, important in connection with the reliability and durability of the products. Since commercialized machines are not always conventionally designed for mechanical property evaluation of nanofiber in any environments; air or fluids. We have, therefore, conducted to develop versatile testers including tension tester for strength measurement and friction tester for handle measurement. In this note, we present typical results for evaluation of mechanical properties of nanofiber/ web fabricated by means of an electrospining method.
Research on Navigation and Obstacle Avoidance Algorithm for Autonomous Mobile Robot in Narrow Area
Authors: Li Huan Xun , Shen Jun Jie , Guo Shuai
Published: January 2011

In order to improve the accuracy and security when autonomous mobile robot moves in narrow area, a real-time navigation and obstacle avoidance algorithm is put forward. The feature extraction method is used to search for the path points, and the angle potential field method is used to search for the target angle. Based on the two methods more accurate environment modeling and navigation for mobile robot in narrow area is realized. The algorithm has been used successfully in the household robot, and the experiment results show it’s accurate and real-time.
FEM Simulation of a Twin-Island Structure Chip in Piezoresistive Pressure Sensor
Authors: Pan Hai Bin , Ding Jian Ning , Cheng Guang Gui , Fan Hui Juan
Published: January 2011

In this paper a twin-island structure in piezoresistive pressure sensor based on MEMS technology has been presented, and a finite element mechanical model has been developed to simulate the static mechanical behavior of this twin-island structure sensor chip, especially the stress distributions in diaphragm of the sensor chip, which has a vital significance on piezoresistive pressure sensors’ sensitivity. The possible impacts of twin-island’s location and twin-island’s width on the stress distributions, as well as the maximum value of compressive stress and tensile stress, have been investigated based on numerical simulation with Finite Element Method (FEM). The simulation results show that twin-island’s location has great effect on the stress distributions in sensor chips’ diaphragms and the sensitivity of piezoresistive pressure sensors, compared with the twin-island’s width.
Tolerance & Fit Query and Dimensioning Program Development in AutoCAD
Authors: Pan Ying Hui
Published: January 2011

For the flaws of query and dimensioning of AutoCAD tolerance & fit, this paper uses Access database and VBA software technology for the secondary development to achieve tolerance & fit automatic inquiry, annotation and updating, so that the designers can quickly carry out the tolerance mark design without the mechanical design manual, consequently improving the drawing efficiency.
Large Sized Workpiece Measurement Based on SIFT
Authors: Xu Zhen Ying , Xu Ran Ran , Cao Dan Dan
Published: January 2011

A measuring method of large sized workpiece based on SIFT algorithm is proposed in this paper. After the different image matching algorithms are compared, SIFT algorithm, which has much more robust, is introduced in detail. Then measuring platform is built, and large sized workpiece is measured by SIFT image stitching and image processing. The experiment proves that SIFT algorithm is viable and advantageous in the measurement of large sized workpiece. At last, the precision and affecting factors are analyzed.
RTCP Function in Five-Axis Machining
Authors: Fan Shu Tian , Yang Wei Ping , Dong Chao Jie
Published: January 2011

Because of the rotate kinematics, the machining of 5-axis brings up the non-linear error. The RTCP (Rotation Tool Center Point) function can always make the interpolated point on the programming track by a real-time linear compensation of CNC system for motion of the rotary axes. Based on detailed analysis of the kinematics principle of 5-axis machine with dual rotary tables, a new design of interpolated algorithm integrated with RTCP function is presented which is simulated in MATLAB, and the result indicates that the algorithm can reduce the non-linear error effectively.
Study on Forecast of Forming Temperature of ABS Resin during Fused Deposition Manufacturing by Fuzzy Comprehensive Evaluation
Authors: Li Chun Ling , Fu Ge Yan , Guo Kai Bo
Published: January 2011

The principle of fused deposition modeling was described, and significant dependence of product quality on nozzle temperature was discussed. The range of forming temperature of ABS resin was investigated by fuzzy comprehensive evaluation, and the optimized theoretical forming temperature was determined to be 216 oC which was very close to the actual value. The progress has important reference value to optimize some other extrusion parameters for technology on FDM machine, thus it underlies fused deposition manufacturing process for functional materials.
Experiment and Analysis of Squirrel Cage Asynchronous Magnetic Coupling
Authors: Yang Chao Jun , Gu Hong Wei , Wang Jing Jing , Ma Ru Yu , Li Zhi Teng , Jiang Sheng Fa
Published: January 2011

Transmission performances of some squirrel cage magnetic couplings, which were different in magnet pole number, slot number, slot depth or slot area, were tested. Experimental results and analysis indicate that these parameters (magnet pole number, slot number, slot depth and slot area) all affect transmission performance of a squirrel cage magnetic coupling. In these factors, deep slot can not only increase slot area to improve a squirrel cage magnetic coupling’s transmission performance, but also can make skin effect on conducting bars more obvious to further improve the transmission performance. Therefore, slot depth affects transmission performance of a squirrel cage magnetic coupling greatly. The experimental results show that a deep slot squirrel cage magnetic coupling’s transmission performance is much better than a common one.
Modal Analysis of Ball Screw Drive System by Finite Element Method
Authors: Zhang Ya Wei , Zhang Wei Min
Published: January 2011

Due to raising ability of five-axis CNC machine tools to machine geometrically complex work pieces efficiently and with higher dimensional accuracy, it is necessary to research its mechanical eigenfrequence of mechanical transmission system. Considering the CNC machine tool’s work table runs slowly and has little damp, the system is considered as an invariable system and the whole system is nearly taken as structure in place of mechanism into account; The Finite Element method(FEM) in ANSYS software is presented in this paper to be used for the solution of the modal analysis of screw drive system for CNC machine, an FEM structural model in ANSYS for the system is developed to estimate the modal characteristics effectively and properly here, the results illuminate that vibration forms of the system and the proportional Gain factor in the position control of CNC drive system is estimated.
Application of Genetic Algorithm in the Structural Optimization of Parallel Sensor
Authors: Liu Fang Hua , Wu Hong Tao
Published: January 2011

The parallel structure of the sensor, which based on Stewart platform, has a direct impact on the technical quota. This article uses Genetic Algorithm to parameterize the model of the sensor. Take the isotropy target of the sensor as objective function, and take five basic structural parameters of the Stewart platform as design variables. Then it optimizes the structure of the sensor. Then apply the virtual prototype technology of ADAMS to simulate. At last, it found the transformation relation between the isotropy target of the sensor and each parameter. It can offer an important gist for optimizing the structure of the sensor.
Fuzzy-Comprehensive Evaluation of Use Reliability of CNC Machine Tools
Authors: Yang Zhao Jun , Zhu Xiao Cui , Jia Ya Zhou , Wang Li Ding , Xu Bin Bin , Li Xiao Bing , Lu Jian Wei
Published: January 2011

This paper chose multi-index to provide a comprehensive evaluation model to evaluate the use reliability of CNC machine tools as a single assessment indicator is biased. As the number of evaluation factors is huge and it is difficult to get the exact values, a fuzzy theory is applied. Reliability mathematical model and maintainability mathematical model were established based on failure data selected from filed test and calculated the estimation values of reliability indexes. Subsequently, a fuzzy comprehensive evaluation mathematical model of CNC machine tools was constructed which combined fuzzy with comprehensive evaluation theory. Using this model could evaluate reliability level of CNC machine tools accurately and integrative.
Research on Mathematical Model of Grinding Force in Gear Form Grinding
Authors: Ren Xiao Zhong , Ding Jun Peng , Su Jian Xin , Du Xiao Yang
Published: January 2011

Based on grinding force formation theory and the surface grinding force formula, the formula of gear form grinding force is obtained by integrating the grinding force in unit width along the involute direction. Simulation analysis and inspection result show that the mathematical model of gear form grinding force is validated. This research is helpful for selecting the technological parameters rationaly in gear form grinding, controlling the wheel dressing and ensuring gear grinding quality.
Numerical Simulation on Temperature Field of the Molten Pool under the Variable Duty Ratio Laser with the Inner Coaxial Powder Feeding
Authors: Shi Gao Lian , Shi Shi Hong , Wu Shao Hua , Wang Yong Kang
Published: January 2011

Aimed at the process of laser rapid prototyping with inner coaxial powder feeding, the finite element model on the transient temperature field of the molten pool is built and the transient temperature field of the molten pool under the laser with variable duty ratio is simulated numerically. The results show that the duty ratio of the laser affects the shape, dimension and power distribution of the molten pool. With the processing parameters: laser power (P)=3000W, outer diameter(d2)=4mm, scanning speed(V=5mm/s), the ideal value of ratio duty(K) is from 0.35 to 0.6. The shape of the molten pool is saddle shape or crescent. The position of the molten pool falls behind the center of the laser beam with the deviation to the both sides. Through shooting the molten pool with the high speed CCD camera, we find the experiments show that the images are close to the numerical simulation nephograms and then demonstrate that the numerical simulations are right.
Research of Special-Shaped Membrane Electrode Assembly for Direct Methanol Fuel Cell
Authors: Wang Xing Xing , Ni Hong Jun , Zhu Yu , Huang Ming Yu , Liao Ping
Published: January 2011

In order to reduce the costs, improve the performances and promote the industry process, basing on calculus and finite element thinking, conceptual design of special-shaped membrane electrode assembly (S-MEA) was proposed, including six shapes. S-MEA size was determined by calculating, admeasuring and devising elaborately, whose basic parameter was gained from experiment datum. S-MEA was made up of titanium mesh anode layer, anode catalyst layer, Nafion membrane layer, cathode catalyst layer, gas diffusion layer and titanium mesh cathode layer in turn, which was different from MEA of the fluid field bipolar plates in the macro-structure but had the same micro-mechanism. Three-dimensional model was devised through Pro/E, planar diagrammatic drawing was created by the software also, and detail drawing was designed further with CAD. The process of preparing S-MEA was researched basing on the design. Then three typical S-MEA prototypes were made by bend-hot-pressing with home-made molds and precision hydraulic machine, including open triangular cross-section MEA, circular cross-section MEA and square cross-section MEA.
Analysis and Development of the Experimental Apparatus of the Laser-Induced Plasma Spectrum
Authors: Meng Chun Mei , Yao Hong Bing , Zhang Yong Kang , Tong Yan Qun
Published: January 2011

This paper mostly summarizes experimental device of laser-induced plasma and taking pictures of plasma plume. The progress in the experimental study on laser-induced plasma was discussed. The experimental apparatus include the laser、delay device; The system of the plasma radiation gathered and radiation received were reviewed. In addition, photos of plasma plume were discussed; at last, dynamic process of laser-induced plasma plume explosion was discussed.
High-Performance Heat-Insulated Coating Fabric and its Technology for Producing
Authors: Qian Yong Ming , Wu Qiang , Zhou Yi Dan
Published: January 2011

A kind of multilayered heat-insulated coating fabric, which can efficiently cuts off the heat generated by sunlight, is made by coating multilayered materials with different functions on fabric surface. Coating material composition, coating process and compatible equipment based on heat-insulated theory are all researched. The result shows that heat-insulated coating fabric bears good heat insulation effect, and the temperature difference between the surface of heat-insulated coating fabric and its inner environment reaches up to over 15 Celsius.
Study on Micstructure and Properties of Ceramic- Lined Composite Steel Pipes Produced by Centrifugal-SHS Process
Authors: Zhu Yu , Sun Shu Gang , Ni Hong Jun , Huang Ming Yu
Published: January 2011

The Al2O3 ceramic-lined steel pipes were made by SHS centrifugal process. The microstructure and phases in ceramic layer were investigated by SEM and X-ray diffraction, microstructure of the ceramic was observed with metallurgical microscope and compression-shear strength of the ceramic was tested by electronic universal testing machine, respectively. The results show that composite steel pipe is composed of three layers, including inner ceramic layer, transition iron layer and outer metal wall, compression-shear strength of the ceramic layer is up to 23 MPa. The percentage of porosity was tested by archimedes principle, it shows that porosity of ceramic was 5%; corrosion resistance of ceramic was tested by mass-loss method, corrosion resistance of ceramic coating is 0.95g/(h•m2).
Study on the Formability of Square Box Deep Drawing of Tailor Rolling Blanks
Authors: Jiang Yin Fang , Fang Lei , Li Zhi Fei , Tang Zhen Zhou
Published: January 2011

As a new lightweight structural sheet metal, tailor rolled blanks has a good prospect in the future development of the automobile industry, and its formability is the current research focus. We use ABAQUS software to analyze the impacts of blank holder force, thickness ratio, die radius, shape and size of sheet metal on the movement of the transition zone and thickness direction strain on the formability of square box of tailor rolled blanks in deep drawing. The results show that, generally, in the punch and side wall corner, where thinning is more serious is a dangerous rupture area, while the inner edge of flange part is prone to wrinkle. When the BHF is 140kN, the connection between the thin side and the transition zone where thinning is severe is also a dangerous area, and even more serious, likewise when the blank thickness ratio arrives at 1.4mm/0.8mm, or the blank size 260mm*260mm, thinning is very serious at the connection between the thin side and the transition zone which is a dangerous rupture area.
Artificial Neural Network versus Similarity Method for Tire Model
Authors: Huang Chen , Long Chen , Jiang Hao Bin
Published: January 2011

Traditionally, similarity method is used to predict the tire forces and moments at the tire/road interface. Because of advances in computer science, students have had an alternative method, the artificial neural net works, to the similarity method. Based on data from a set of experimental available data, we compared the prediction of the similarity model and the neural network model by genetic algorithm. The latter showed a slightly (about 9%, 18%) but significantly better performance. The accuracy of both approaches was low at the population level, but both models may be used to estimate longitudinal and lateral tire tread and sidewall deflections during braking, traction and cornering.
Friction Behaviors of SiC Particle-Reinforced Cu Matrix Composites
Authors: Dai Feng Ze , Xu Xiao Jing , Lu J.Z. , Zhang Y.K. , Cai Lan
Published: January 2011

SiC particle reinforced Cu composite was fabricated by powder metallurgy and hot extrusion process. The friction behaviour of pure Cu, braze and composites was studied on a block-on-ring test. The blocks were slid against 40Cr steel rings under the lubrication of 232# machinery oil. It shows that the wear rate of pure Cu is about then times of the 5 vol.% Cu composite at a normal load of 300 N. The satisfied wear resistance prove the SiC is a promising reinforcement material for Cu matrix composite. However, the 20 vol.% SiC did not exhibit prospected wear resistance. The discussion of this phenomenon was conducted.
Optimization Methods of High-Speed Machining Processing Based on Fuzzy Neural Network
Authors: Sun Quan Ping
Published: January 2011

A model of five layers of fuzzy neural network which is appropriate for high-speed machining (HSM) processing optimization is proposed to fully exert the advantages of HSM. This model built a mapping relationship among the credibility of three-optimization objective "efficiency priority", "quality priority" and "precision priority”, material removal rate, cutter rigidity, machine-tool precision, and the smooth degree and fitting error of tool path. Gradient descent method is used to conduct training of network on the basis of orthogonal test. The constraints are also given in the HSM processing optimization objective. A prototype system of HSM processing optimization is developed based on fuzzy neural network. The result of test shows that not only the systems runs reliably and steady, but also the processing scheme optimized is economic and reasonable.
Investigation of Laser Shock Processing on the Key Weld Zone of Offshore Platform
Authors: Liang Guo Ming , Zhang Zhao Yang , Chen Yong Ming , Xu Zhi Min
Published: January 2011

Effects of laser power and spot diameter on residual stress and micro-hardness of the welding of ship plate (ASTM A 131) by laser shock processing (LSP) has been investigated. While laser power is 45.9J, spot diameter less thanφ3 mm, the distribution of residual stress in welding line occurs obvious variation, which residual stress compressive increase obviously with spot diameter decrease. When power density is bigger than 1.2×1010 W/cm2, the surface residual stresses and micro-hardness of the welded specimen occur change by LSP. The results show that mechanical properties of the welded joints will be improved by LSP. Laser shock processing produced a residual compressive stress layer on the surface of the target, which is an effective method for protecting the welded steel structures against stress corrosion.
No-Excess Block Construction in Oil Drilling Platform Sevan Driller
Authors: Zhang Yong Kang , Yang Chao Jun , Guan Chun Song , Ni Tao , Zhuang Jian Jun
Published: January 2011

The technique of hull block accuracy control is the main concern for modern shipbuilding. The method of no-excess block construction is introduced in Sevan Driller, the world’s first cylindrical ultra-deep offshore drilling platform. According to the structural characteristics of the drilling platform and production capacity, the partition and construction programs of the hull blocks are proposed. Modeling and drawing for platform in the design stage is analyzed. In the manufacturing stage, the factors affecting the block accuracy include plate-cutting, plate alignment, marking, assembling and welding. Additionally, the range of accuracy controlling aspect and compensation values are confirmed. The application of no-excess block construction in this drilling platform results in the improved quality of the drilling platform, reduced shipbuilding costs and the shortened shipbuilding cycle.
Fatigue Crack Propagation Experiment and Simulation on 7050 Aluminum Alloy
Authors: Ren Xu Dong , Huangfu Yong Zhuo , Zhang Yong Kang , Jiang Da Wei , Zhang Tian
Published: January 2011

In this paper, an experiment of fatigue crack propagation in 7050 aluminum alloy was presented. Laser shock processing (LSP) is used to shock the crack surface. Compared with the specimen without LSP, the fatigue life after LSP increased greatly. The simulation of the fatigue crack growth in 7050 aluminum alloy is implemented in FRANC2D. Simulating result is in accordance with the result of the experiment well. Laser shock processing increases the fatigue life and reduce fatigue crack growth rate, it has good prospect on the study of crack arrestment.
The Investigation of the First Order Size Effect in Micro-Plastic Forming
Authors: Wang Yun , Wang Jing Jing , Wang Jia Xi , Xu Zhen Ying , Dong Pei Long
Published: January 2011

With the rapid development of MEMS and electronic industry, the demands for micro-parts are increasing gradually. However, size effects make the traditional forming theories and deformation mechanism not suitable in micro forming field. In this paper, we introduced the classification of the size effects. It pointed out that the size effects can be divided into the first order and the second order size effects in the micro-forming. For the first order size effects, the theory model was established based on the surface layer model. It also clarified the phenomenon that flow stress of the blank reduced with the increase of the ratio of grain size and thickness (t decreases or d increases). Finally, the model was verified with the experimental results of the first order size effects in the references, confirming the effectiveness of the theoretical model. It provides a method to theoretically and experimentally study the micro-plastic forming.
An Efficient and Accurate Method of Relief Segmentation
Authors: Xiang Bo , An Lu Ling , Sun Jin Hu , Zhou Lai Shui
Published: January 2011

Authors create a relief segmentation method on point cloud model, and solve such problems as how to store the point cloud data, how to obtain the final contour, how to define Snakes energy term and how to acquire region from its contour. Firstly, the point cloud data is resampled by applying Z-MAP grid data structure. Then initial contour is drawn by interaction, and the total energy of the contour is computed to optimize the contour to the energy-minimizing position by iterations. Finally, the contour is scattered as points, and the points are mapped to Z-MAP grids for projection points. According to these projection points, the region is obtained.
Study of the Produce Technology and its Material Characteristic of Cold-Roll Twisted Steel
Authors: Xing Bang Sheng , Du Changlun , Wang Xue Feng
Published: January 2011

The article is about the produce technology and its demands of the cold-rolled twist steel, together with the details of its experimental methods. It places great emphrasis on the study of the characteristics of the micro-organization, science of the motion and force, the patterns of the elasticity, as well as the loading characteristic of prestressed disc. It also discusses the economic benefits of the application of the cold-roll, coming to the conclusion that the technology above is simple in design and production, and that the product is to be a new sort of constructural materials with higher benefit, greater strength, better toughness, and better gripping power.
Mechanism Research of Low-Stress Threshold of Plastic Accumulation under Super-Low Repeated Impact Stress
Authors: Fu Ge Yan , Shi Shi Hong
Published: January 2011

It is discovered that, if material has been applied with super-low impact stress that for certain times, macroscopic plastic deformation may be happen. The stress can be far below the static yield limit of material. The strain rate will decrease with impact times and distance from the surface. For exploring the micro-mechanism of the new deformation phenomena, the paper presents the theory of dislocation slip based on the principle of superposed dislocation vibration and the microscopic dislocation slip model under low-stress repeated impact. Analysis showed that the stress threshold is related to not only material damping, but also the frequency of repeated impact. Lower material damping and higher frequency of repeated impact are favorable to dislocation slip and, consequently, favorable to macroscopic plastic accumulation. Stress threshold being closely related to impact frequency is an important feature of repeated-impact plastic accumulation.
Study on the VF-DPC-SVM Strategy for Three-Level Rectifier
Authors: Tan Guo Jun , Zhao Zhang Fei , Ye Zong Bin , Liu Yi
Published: January 2011

In this paper, a constant switching frequency direct power control strategy based on the virtual line-flux-linkage oriented system for three-level PWM rectifier using space vector modulation (VF-DPC-SVM) is proposed, which is on the basis of the mathematic model of the PWM rectifier, the instantaneous reactive power and the vector control theory. Compared with the traditional control strategy, the proposed VF-DPC-SVM method guarantees a fixed switching frequency and realizes a better dynamic performance. The simulations and experiments indicate that the system has a better dynamic performance with lower harmonic current by use of the control strategy and can achieve the decoupling control of the active and reactive power.
Laser Cladding of Ni-Based Hardfacing Alloy Replacing Stellite06
Authors: Liu Shuang , Shi Shi Hong , Fu Ge Yan , Wei Hong Pu
Published: January 2011

For the disadvantages of Co element, such as rarity, high price and nuclear pollution, the Co-based materials will be eliminated in the valves which are used in the third and fourth-generation nuclear plants. In this paper, the composition of a Co-free Ni-based alloy was designed. With laser cladding technology, the Ni-based coatings were obtained. Microstructure of the coatings was characterized by optical microscopy (OM) and scanning electron microscopy (SEM). The phases in the surface layer were identified by X-ray diffraction (XRD) and energy-dispersive spectrometer (EDS). And the wear resistance of the coatings were tested and compared with Co-based alloy. The results showed that the coatings were mainly made of dendrite phases and interdendritic constituents. The dendrites were characterized of primary dendrites M7C3 and M23(CB)6 and some Ni3Al round particles uniformly dispersed in the γ-Ni matrix. There were a bit of Ni3B and Ni3Si phases in the coatings. The wear volume loss of Ni-based alloy was close to of Co-based alloy.
Structural Topology Optimization for Street Lamp Bracket
Authors: Wang Yong , Zhu Guo Niu , Zhu Zheng Wei
Published: January 2011

Structural topology optimization has got a general acceptance in recent years in mechanical design due to its powerful technique for conceptual design. The shortcoming of current development process of mechanical design is discussed and a new approach with structural topology optimization is put forward. The application of the method demonstrates that through innovative utilization of the topology optimization techniques, a multitude of conceptual design proposals based on the design space and design targets can be obtained and then a CAD model with high quality which has a positive impact on the development process is also available.