bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical Simulation of Fretting Wear in Press-Fitted Shaft Considering the Running-In Period
Authors: Lee Dong Hyung , Kwon Seok Jin , You Won Hee
Published: October 2009

In this paper the fretting wear simulation technique with the press-fitted specimens have been developed, which can consider the running-in period of total wear process by adopting nonlinear wear coefficient. The amount of microslip and contact variable at press-fitted and at bending loaded condition of press-fitted shaft was analysed by applying finite element method. With the finite element analysis result, a numerical approach was applied to predict fretting wear based on modified Archard's equation and updating the change of contact pressure caused by local wear with influence function method. The predicted wear profiles of press-fitted specimens at the contact edge were compared with the experimental results obtained by rotating bending fatigue tests. It is shown that the predicted wear profiles considering the running-in period with nonlinear wear coefficent is consistent with experimental results than that with constant wear coefficient. Therefore, the fretting wear simulation technique proposed is feasible and efficient for numerical simulation of fretting wear on press fits at the initial stage of fatigue life.
Development of Cementless Fly Ash Based Alkali-Activated Mortar
Authors: Koh Kyung Taek , Kang Su Tae , Ryu Gum Sung , Kang Hyun Jin , Lee Jang Hwa
Published: October 2009

This study investigates the effects of alkaline activators and curing method on the compressive strength of mortar for the development of cementless alkali-activated concrete using 100% of fly ash as binder. Results reveal that the compressive strength improved according to the increase of the molar concentration of NaOH. In addition, molar ratio Na2O to SiO2 of 1.12 activated the reaction of fly ash with Si and Al constituents and resulted in the most remarkable development of strength. In the case of mortar requiring high strength at early age, higher curing temperatures appeared to be advantages. Curing at 60°C during 48 hours is recommended for requiring high strength at age 28days. Moreover, performing atmospheric curing after high temperature curing appeared to be more effective for the development of strength than water curing. Based on these results, it has been analyzed that alkaline activators fabricated with proportions of 1:1 of 9M NaOH and sodium silicate should be used and that atmospheric curing should be performed after curing at 60°C during 48 hours to produce high strength alkali-activated mortar exhibiting compressive strength of 70MPa at age 28 days.
Study on Recycled Aggregate Concrete Frame Joints with Method of Nonlinear Finite Element
Authors: Xiao Jian Zhuang , Tawana M.M. , Zhu Xiao Hui
Published: October 2009

With the achievements made in the research of mechanical properties for recycled aggregate concrete, this paper adopts the method of nonlinear finite element to analyze the seismic behavior of frame joints. The frame joints are made of recycled aggregate concrete. It also takes into account the bond behavior between steel bars and recycled aggregate concrete in the core area of the joints, and the force-displacement curve of the joints is calculated. Nonlinear finite element analysis shows that the results of the calculations are in accordance with the test results. It is concluded in this paper that, built models with nonlinear finite element method can be applied in simulating exactly the same seismic behavior of frame joints under low frequency reversed lateral loading.
Fatigue Life Enhancement of Welded Steel-Steel Composite during Crack Growth from Weak to Strong Steel: An Experimental Validation
Authors: Bhat Sunil , Ukadgaonker Vijay G.
Published: October 2009

Strength mismatch effect across weld interfaces, generated by welding weak and strong steels, influences fatigue and fracture properties of a welded bimetallic composite. Advancing fatigue crack tip in weak parent steel is shielded from the remote load when it reaches near the interface of ultra strong weld steel. Entry of crack tip plasticity into weld steel induces load transfer towards weld which dips crack growth rates thereby enhancing the fatigue life of the composite. A computational model for fatigue life prediction of strength mismatched welded composite under K dominant conditions is validated by experimental work in this paper. Notched bimetallic compact tension specimens, prepared by electron beam welding of weak alloy and strong maraging steels, are subjected to fatigue testing in high cycle regime.
Research on Waterproof-Adhesive Layer’s Shearing Strength in Cement Concrete Bridge Pavement
Authors: Wu Shao Peng , Wang Hong , Han Jun , Lin Jun Tao
Published: October 2009

The waterproof-adhesive layer plays an important role in cement concrete bridge pavement. The adhesive strength of the layer between the cement concrete deck and the asphalt pavement may affect the bridge’s service performance directly. In the study, the direct shearing-strength experiment between the asphalt pavement, waterproof adhesive layer and the cement concrete deck was done in a laboratory. Some testing parameters were considered, including different loading speed, surface processing mode of the cement concrete deck and adhesive materials. The result shows that the coarser the surface of the cement concrete deck is, the larger the shearing strength of the adhesive material is at the same temperature. The loading speed of the shearing test has important effect on the shearing strength. The rapid loading speed can cause high shearing strength. Especially, the experiment datum indicates that the relationship between the loading speed of the test and the shearing strength can be described using the power exponent. Ultimately, the study is aimed at providing bridge engineers with an efficient testing method that attempts to increase the prediction accuracy of adhesive strength for more reliable design.
Finite Element Prediction of Laser Shock Peened Surface Modifications in Ti-6Al-4V Alloy
Authors: Frija Mounir , Fathallah Raouf , Hassine T.
Published: October 2009

This paper presents a numerical simulation of the Laser Shock Peening process (LSP) using ﬁnite element method. The majority of the controlling parameters of the process have been taken into account. The laser loading has been characterised by using a repetitive time Gaussian increment pressure applied uniformly at circular impacted zone. The behavior of the subjected material is supposed to be elasto-visco-plastic coupled with damage using the Johnson Cook law with his shear failure model. The proposed model leads to obtain the surface inducing modifications, which are classified in this work into three categories: (i) the in-depth residual stress profile, (ii) the induced plastic strains profile and (iii) also the superficial damage which can be induced in few cases where the operating conditions are not well chosen. An application on a laser shock peened super alloy Ti-6Al-4V has been carried out. The comparison of the residual stresses, obtained by X-ray diffraction method and by ﬁnite element calculation, shows a good correlation.
3D Numerical Simulation and Fatigue Life Prediction of High Strength Threaded Bolt
Authors: Zhao Li Bin , Liu Feng Rui , Zhang Jian Yu
Published: October 2009

An three-dimensional FE model of threaded connection is proposed by means of the general purpose program ANSYS. The model is accurately constructed according to the helical thread profiles. The mechanical behavior of each bolt subjected to eccentrically loading is investigated and the stress distribution is discussed detailedly. Based on the stress level, the fatigue life of threaded connection is predicted by the cumulative damage method. This work can provide a deeply understanding on the mechanics behavior of bolt connection in engineering, especially for its application on the appending equipments of airplane.
Damage Mechanical Analysis of Spherical Cavity Expansion
Authors: Wu Guo Hui , Wang Kun , Tang Li Qiang
Published: October 2009

In this paper, the method of continuum damage mechanics is used to construct the damage constitutive equations for the material, and governing equations are obtained based on the assumption of spherical symmetry. Then the stress value is taken as basic unknown parameter to solve these equations, the distribution of materials damage field was also obtained. Finally, the influence of different damage parameters on average distribution is discussed. Thus the paper lays a necessary foundation for research on materials damage evolution law.
Mathematical Modelling of Service Life Prediction as a Part of the Maintenance Process
Authors: Aberšek Boris , Flašker Jože
Published: October 2009

In this paper, the concepts of preventive maintenance are pres¬ented in first part, and second part of the paper present several mathematical models for prediction service life as a base for preventive maintenance forecasting. These models aid in determining the frequency of inspec¬tions that will allow the condition of a piece of equipment to be determined in order to plan an appropriate maintenance action.
The problem of determination of the service life is directly related to geometry, multiaxial loadings, materials and appropriate models for prediction of the failure propagation. The more precise modelling of these input parameters the more precise and reliable the results are. Therefore in the paper we will present models and procedures for calculations service life, remain service life and/or service control cycle.
Fracture Properties of Epoxy Asphalt Mixture
Authors: Chen Xian Hua , Li Hong Tao , Qian Zhen Dong
Published: October 2009

The fracture properties of the thermo-setting materials of epoxy asphalt mixture were evaluated based on J-integral concept and ultimate strength and compared to that of HMA with thermo-plastic binder materials. Totally 60 specimens cored from SGC with different notches were tested with SCB test under a temperature of -10°C and 20°C. The experimental results reveals that epoxy asphalt mixture has a super higher resistance of fracture at low temperature than thermo-plastic HMA due to its super high tensile strength and flexibility, and the influences of temperature on the fracture resistance of EAM is not so significant as that of thermo-plastic HMA. Good repeatability of SCB test results indicates the capability of the SCB test to be useful for measuring the fracture toughness of epoxy asphalt mixture.
Mixed-Mode Stress Intensity Factors by Mesh Free Galerkin Method
Authors: Wen P.H. , M.H.Aliabadi Ferri
Published: October 2009

An element-free Galerkin method is developed using radial basis interpolation functions to evaluate static and dynamic mixed-mode stress intensity factors. For dynamic problems, the Laplace transform technique is used to transform the time domain problem to frequency domain. The so-called enriched radial basis functions are introduced to accurately capture the singularity of stress at crack tip. The accuracy and convergence of mesh free Galerkin method with enriched radial basis functions for the two-dimensional static and dynamic fracture mechanics are demonstrated through several benchmark examples. Comparisons have been made with benchmarks and solutions obtained by the boundary element method.
Investigation of Cavity Wind Rotor with Three Blades Vertical Axis
Authors: Ma Wei , Wang Ji Guang , Li Ji Shun , Liu Yong Gang
Published: October 2009

A new type of resistance wind rotor with power-transmission cavity and three blades vertical axis is proposed. Computational Fluid Dynamics (CFD) is employed to numerically research the performance of blades in five typical rotation angles. The pressure of the wind rotor in the fluid field is got based on the static pressure contours of the blades in the five rotation angles. The simulation results show the positive pressure and the negative pressure appear around the blades in a cycle. Both of them can be motive power and resistance power to the wind rotor. The both power cancel out and the total torque output varies with the rotate location. Simulation results show that the largest torque appears at 90°while the least torque appears at 30°. Then, an instrument that measures torque output of wind rotor is designed. The torque output of the rotor in the five typed rotation angles is tested in a circle. The result indicates that distribution of the static torque output is like cosine wave in a cycle which is consistent with the results of the CFD. The studies provide the theory basis and the experimental introduction of the wind rotor designing.
A Contrast of Generation Sinusoidal Fringe Pattern Method Based on Phase Measurement Profilometry
Authors: He Wan Tao , Ren Wen Chao , Che Xiang Qian , Wang Shao Sheng
Published: October 2009

Optical 3D measurement systems are used in a lot of applications, for instance for quality control and reverse engineering. A structured light active optical 3D measurement method are very often based on projection sinusoidal fringe pattern on the object. The key element of such a shape measurement method is how to generate sinusoidal fringe pattern. The purpose of this paper is to review the method of generation sinusoidal fringe pattern and contrast the two chief method from the specific viewpoint based phase measurement profilmetry. Experiment verification of the performance of each generation method is provided and finally some suggestions on generation method for phase measurement profilometry applications is offered.
On the Biomechanical Design of the Walking Assistance Mechanism in Aided-Walking Wheelchair
Authors: Zhang Li Xun , Yi Lei , Wang Lan , Wang Kang
Published: October 2009

A new kind of walking assistance mechanism in aided-walking wheelchair is proposed to help stroke and cord injury patients on gait rehabilitation training and aided-walking indoor and outdoor. Each side of the walking assistance mechanism, which is a double-crank linkage mechanism actuated by one driver, assists the motion of thigh and shank synchronously. The mechanism can control the walking gait of both legs to assist the patients in walking and gait rehabilitation training. The mechanism is analyzed, and the optimal proportion of the structure dimension suitable for different person is obtained according to the clinical gait analysis data. The simulation results show that the walking assistance mechanism can simulate the nature gait during human walking and realize the walking assistance and gait rehabilitation training function.
Structural Design and the State of Motion Analyzes for Multi-Degree-of-Freedom Electro-Hydraulic Mix-Drive Motion Simulator
Authors: Zhou Yue Fa , Ji Xiang Chun , Li Hong Liang , Zhang Zhao Kui
Published: October 2009

This paper has designed a multi-degree-of-freedom electro-hydraulic mix- drive motion simulator, which could move and turn spatially. It has both the advantages of the parallel turnplate and the series turnplate. The homogeneous coordinate transformation matrix was used to analyze the simulator’s state of motion. The position and attitude matrix for describing the simulator movement has been obtained. The kinematics equation for showing the relation of the positions between hydraulic drive rod and the turnplate was given, thus provided the theory basis for the further research to the simulator.
Optimal Research of Actuator Placement for Piezoelectric Smart Structure
Authors: Wang Wei Yuan , Xue Kai , Shi Dong Yan
Published: October 2009

The purpose of this paper is to investigate the optimal placement of piezoelectric actuator for active vibration control of smart structure. The structures can be described in the modal space based on the independent modal space control method and dynamic equations derived from finite element model. The modal damping ratios are derived from modal equations and an optimal target is given by maximizing the modal damping ratios. Accumulation method is adopted to the optimization calculation. Simulations are carried out for active vibration control of a conical shell with distributed piezoelectric actuators. Control effects proved the validity of the optimal method above by compared with the non-optimal results. The optimal method in this paper gives a useful guide for quantity optimization of actuators to piezoelectric structures.
Design for Saving Energy Based on Energy Flow Analysis Method and CAE Technology
Authors: Wang Hong Lei , Xiang Dong , Duan Guang Hong
Published: October 2009

This paper presents the design method of electromechanical products for saving energy based on energy flow analysis. The energy transfer model and energy correlation model are built through analyzing the relation of energy flow and products performance in order to address the conflict between energy saving and performance optimization. Based on the energy transfer model, the performance pertinences and performance margins of electromechanical products are analyzed with CAE technology and value engineering theory. Finally, the split air-conditioner’s outdoor unit is studied and the design method for saving energy based on energy flow analysis is adopted to solve the conflict between air flow increasing and noise reduction.
Convective Heat Transfer Measurements of Die-Casting Heat Sinks
Authors: Jou Rong Yuan
Published: October 2009

For applications of high-power LED illumination and advanced CPU electronic cooling, since the traditional plate heat sinks by aluminum extrusion are simple geometry only and with limited thermal performance, a new design and new fabrication process of heat sink for high-density heat flux applications is inevitable. In this study, a heat sink fabricated by vacuum die-casting is analyzed. To evaluate the thermal performance of this heat sink, two experiments, free convection measurements in an enclosure and forced convection measurements in a wind tunnel, are conducted by two experimental methods of thermocouples and IR thermograph. As to free convection experiments, compared to the free convection over a plate, temperature decrement by the attached casting of pin-fin heat sink is 46.2% for the input power of 10W. In the case of 15W heating power, temperature distribution along center pin shows uniformly distributed temperature along length direction, but there is a temperature difference of 9.5°C,varied from 86.9°C to 77.4°C, at outer pin. As to the case of 10W heating power, there is a temperature difference of 6.5°C, varied from 69.2.9°C to 62.6°C, at the outer pin. Furthermore, forced convection experiments show that resistances of heat-sink casting are decreased when Reynolds numbers are increased, and a linear relationship between pressure drop and Reynolds number is noticed. Base on the measurement results, this heat sink casting can be a feasible thermal solution of LED and high-power chip products.
A Study on Ultrasonic Vibration Milling of Inconel 718
Authors: Hsu Chun Yao , Tsao Chung Chen , Huang C.H. , Lin Yu Cheng
Published: October 2009

Increasing the productivity and the quality of the machined parts are the main challenges of manufacturing industry, in particular for difficult-to-machine materials, such as Inconel 718, employed in aeronautic and aerospace applications. A L18 (2×37) orthogonal array (OA) and signal-to-noise (S/N) were employed to analyze the effect of mill parameters when milling Inconel 718. Experimental results indicated that the cutting tool, depth of cut, cutting speed, feed rate, frequency and coolant have statistical and physical significance on the flank wear, surface roughness and cutting force obtained, respectively.
Experimental and Structural Analysis on Strength of Thermit Welding
Authors: He Bo , Sun Chang Qing
Published: October 2009

War-broken parts could be repaired quickly without power and gas in the field by using the thermit welding technology. In this paper, experimental and structural analysis on strength of thermit welding was made. According to orthogonal experiments, the pressure mode was found to influence tensile stress most, then the warm-up temperature and the welding line clearance. By quadratic general revolving combination design, the mathematics equation indicating the relation of welding tensile stress, warm-up temperature, pressing time and welding line clearance was obtained, and the optimized welding parameters to achieve the best tensile strength were decided as well. By further analysis on microstructures and fractures of welded seam, fusion zone and HAZ of thermit steel, conclusion was made that it was of vital significance to adopt welding-after-peening method for improving the strength of the welded seam.
A Semantic Gateway Architecture for System Integration in Networked Manufacturing
Authors: Song Yu Chuan , Lei Qi , Liu Fei
Published: October 2009

Intense competition drives the need for dynamic and flexible integration of dispersed and heterogeneous information systems. This paper proposes a semantic gateway architecture for system integration in networked manufacturing to solve the semantic heterogeneity problems. The system integration mode based on semantic gateway is set up to enable unified expression and analysis of the information to be integrated, so that the flexibility and transparency of integration between heterogeneous systems are significantly improved.
Application of Rigid/Visco-Plastic Element Free Galerkin Method in Three-Dimensional Bulk Metal Forming Processes
Authors: Lu Ping , Wu Xin , Zhao Guo Qun , Jiang Kai Yong , Guan Yan Jin
Published: October 2009

Combining element free Galerkin method with rigid/visco-plastic flow theory, the paper establishes the three-dimensional rigid/visco-plastic element free Galerkin method, and introduces it to analyze three-dimensional bulk metal forming processes. The velocity field is approximated by MLS method. Employing the incomplete generalized variation principle, stiffness matrix equation and solution formulas are derived. And STL format discrete triangular patches are used to describe the mould cavity. An analysis program for simulating three-dimensional bulk metal forming processes is developed. The program is capable of simulating three-dimensional unsteady bulk metal forming processes with severe deformation and arbitrarily shaped dies. A numerical example is analyzed. Numerical results such as material flow patterns and distributions of the effective stress are obtained. The effectiveness and validity of the proposed method and techniques are demonstrated by comparing with results obtained by using commercial finite element software.
Soy-Based Polyurethane Foam Reinforced with Carbon Nanotubes
Authors: Liang Kai Wen , Shi Sheldon Q.
Published: October 2009

The objective of this research is to develop soy-based polyurethane (PU) foam product reinforced with carbon nanotubes. The shortage of petroleum and the increasing concern on environmental issues have resulted in an interest in using renewable substances as building blocks for polymer applications. Multi-walled carbon nanotube (MWNT) was used in this study to reinforce the soy-based polyurethane foam. The compressive and mechanical properties of the composites were enhanced with adding carbon nanotubes. Neat polyurethane was used as a control. Soy-based polyurethane / carbon nanotubes composites with loadings of 0.5 and 1.0 wt% were fabricated. The compressive, flexural, and tensile properties of MWNTs-PU foams were improved by 24, 30 and 30 %, respectively, as compared with the neat PU foam. The greatest enhancements on compressive and flexural properties were shown at the 0.5 wt% MWNT loading, while the highest tensile stress enhancement of PU foam was shown at 1 wt% MWNT loading.
Material Point Method in Impact Engineering Problems
Authors: Chen Wei Dong , Zhang Zhong
Published: October 2009

The basic theory of material point method (MPM), which is a new meshfree method,was briefly introduced in this paper.MPM takes advantage of both Eurlerian and Lagrangian methods. It avoids the mesh distortion and tangling issues associated with Lagrangian methods and the advection errors associated with Eulerian methods. A MPM computational code called MPM-EXPLICIT with the Von-mises material strength model and Shock equation of state was developed in FORTRAN 90, and was used to compute various impact problems. The calculated result and experimental result were compared to confirm the accuracy of the code. The results obtained by using the MPM, FEM and SPH were compared. It shows that MPM possesses many prominent features. This study indicates that the material point method is an efficient and promising method for simulating the impact problems.
Analysis on Microstructure of AlSi7Cu5 Alloy by Slope Near-Liquidus Method
Authors: Xie Shi Kun , Zheng Xiao Qiu , Yi Rong Xi , Pan Xiao Liang , Guo Xiu Yan
Published: October 2009

SSM(Semi-solid metal) forming has been developed to become a novel technology in the 21st century for the formation of near net shape components, competing with conventional casting and forging technologies. In this paper, the casting microstructure and its change during remelting of AlSi7Cu5 alloy casting by slope near-liquidus method were researched. Experiments show that it has a significant impact on microstructure by cooling method, the thermal conductivity of the casting mold and casting method. The microstructure of AlSi7Cu5 alloy obtained by slope near-liquidus method at 600°C is uniform and small equiaxed Its average grain diameter is about 55.2um, and its average grain size roundness is about 2.13. The reheated microstructure which can be applied in thixo-forming preferable will be obtained by keeping constant temperature 25min at 580°C.
Structure and Properties of TaCx Coating on Biomedical 316L Stainless Steel by RF Magnetron Sputtering
Authors: Ding Ming Hui , Wang Ben Li , Li Li , Zheng Yu Feng
Published: October 2009

In this paper, the TaCx coating with thickness around 1.2 μm was prepared by radio frequency magnetron sputtering technique on the 316L stainless steel substrate to improve its hemocompatibility. The structure and morphology of the coating were characterized by XRD and SEM. The XRD results indicated that TaCx, as a new species, appeared on the surface of the 316L stainless steel substrate. SEM images showed that the surface morphology of the TaCx coating was uniform and dense. The mechanical characteristics of the coating were measured by nanoindentation, giving a nanohardness of 13 GPa and a Young’s modulus of 210 GPa. The adhesion strength of the TaCx coating to 316L stainless steel depended on the sputtering bias voltages and increased for a higher bias voltage. The hemocompatibility of the TaCx coating, as evaluated by platelet adhesion tests, was compared to that of the bare 316L stainless steel. The results indicated that the hemocompatibility of 316L stainless steel with TaCx coating was significantly improved as compared to the original one.
Experimental Research on Diamond String Bead Wire Cutting the Steel-Based Material
Authors: Zhang Lan , Lu Ze Sheng , Meng Qing Xin , Wang Li Quan , Gong Hai Xia
Published: October 2009

Diamond wire saw was a tool which is used to cut the steel-based material, its grinding mechanism was researched in the paper. Based on technical characteristic of the diamond wire, a string of diamond beads in the cutting moment was detected by using the electron microscope. Wear figuration and invalidation reason of the diamond beads was analyzed, and mathematic relation among wear rate, feed velocity and cutting velocity of the diamond wire were educed, and reasonable cutting parameters were received. In order to validate the mathematic model, the experiment was finished. When the diamomd wire saw is used to cut the steel-based material, its two experiential formulas of radial feed force and tangent cutting force are educed by using the orthogonal regression method. In the formula, radial force and cutting force is increasing with augment of the workpiece breadth, ridial feed velocity and cutting velocity, and influence of the workpiece breadth to the cutting force is more than to the radial force. Meanwhile, experiment show yet that error between theory cutting(or feed) force and actual cutting(or feed) force is in the reasonable scope.
Image Processing Algorithm for Tracking and Picking an Object for an Open Platform Mobile Robot
Authors: Ho Chao Ching
Published: October 2009

Designing a visual tracking system to pick-and-place an object is a complex task because a large amount of video data must be transmitted and processed in real time. In this work, a mobile robot visual control system is proposed which uses a stereo vision to acquire the 3D positions of a target color ball and to control an end-effector to pick the ball up and place it in the specified location. This mobile robotic system is based on the Open Source Computer Vision Library for programming framework with portable components, off-the-shelf commercial hardware, and minimal programming. Two calibrated web cameras are used to track the color ball and a 2-axis end-effector is controlled to pick up the tracked color ball. The visual tracking and servo system as designed in this work is less sensitive to lighting influences and thus performs more efficiently. Experimental results show that the open platform based robot vision system successfully finishes the pick-and-place task and could be scalable to many diverse areas of robotics research
On the Firing Test Properties of Thinfilm Metallic Initiators
Authors: Shyu Jenq Huey , Lai I Tsung , Chang Ta , Wang Yun Cheng , Wu Yan Chyuan , Lu Hao Yi
Published: October 2009

The aim of this study was to investigate the firing test properties of NiCr alloy thin film bridge electro-initiators(detonators). The function time of firing test was characterized in terms of their area, shape, resistance, and thickness of thin film bridge electro-initiators(detonators). It is found that samples with small film bridge area show profound and positive influence on the function time of firing test. The shortest function time is 120 μs（3.165 Ω）.
Facility Planning for TFT-LCD Array Fab
Authors: Chen James C. , Hu Shu Jen , Chen Yu Hsin , Yang C.L. , Sun Cheng Ju , Chen C.W.
Published: October 2009

Facility planning is crucial to the performance of array fabs in Thin Film Transistor - Liquid Crystal Display (TFT-LCD) industry. In order to avoid costly changes and modifications of fab layouts at the installation or production stages, the designers should carefully evaluate design alternatives and then select the best one during the design stage. A TFT-LCD manufacturing process consists of four basic processes: array, color filter, cell, and module. This research proposes an Array Fab Design Procedure (AFDP) to conduct quick calculations to develop and evaluate initial design alternatives for TFT-LCD array fabs. A series of practical formulae are presented to sequentially determine the related design parameters. The proposed AFDP provides a basis for rapid modeling and evaluation of array fab designs. AFDP is developed in Microsoft Visual Basic and data from real array fabs are used to demonstrate its effectiveness and efficiency. Results indicate that AFDP can quickly calculate the related fab design parameters. “Job shop with small bays” leads to the least average sheet moving distance. With AFDP as a tool, fab designers can evaluate design alternatives and conduct what-if analysis in the initial phase of fab design.
A Novel 3D Mesh Segmentation Method of Algebraic Models in Reverse Engineering
Authors: Liu Peng Xin , Wang Yang
Published: October 2009

Conventional engineering parts usually composed by algebraic surfaces are important investigation objects of reverse engineering. In this paper a step segmentation method for algebraic models is proposed. The mesh normals and curvedness of every vertex are estimated as a shape descriptor. In the first segmentation fourteen directions are chosen initially, and a k-means algorithm according to the normal vectors is used, then the surface is divided to form patches by a region-growing scheme, as well as some sharp edges or flat areas are detected. In order to identify algebraic surface, curvedness of a patch is set as the criterion by which the surface merged into near constant curvedness region. Especially a novel mean shift algorithm is adopted in this method, that a powerful technique for clustering in image process, and is extended to normal filtering while preserving the features to increase robustness of the method. Experimental evaluations using scan data or noise data demonstrate the efficiency of the proposed method.
Research on Simulation System of the Interfacing Apparatus of Underwater Vehicle Based on VR
Authors: Chang Yan Yan , Meng Qing Xin , Wang He Chun
Published: October 2009

Underwater interfacing technique is the key technique of the underwater vehicle. Now the technique is mainly used in the submarine rescue. Based on the structural characteristics of the model of BSAV-Ⅰand the interfacing apparatus with the manipulators which are made by Harbin Engineering University, a group of equations were defined and solved based on the six freedom motion of the model. The software Creator and Vega were used to build virtual ocean geographic environment and the deep submergence rescue vehicle(DSRV), the virtual simulation system is created，with which the virtual simulation of the docking process of DSRV and the disable marine is done. Except this, the research on simulation system of the interfacing apparatus of the underwater vehicle based on VR can test the docking strategy, find the problems in docking and improve the structure of the interfacing apparatus.
Multi-Axis EDM CNC System Based on RT-Linux
Authors: Huang Hai Peng , Chi Guan Xin , Wang Zhen Long
Published: October 2009

In order to manufacture geometrically complex or hard material parts, a new kind of multi-axis electro-discharge machining (EDM) computer numerical control (CNC) system, which is based on RT-Linux platform, was presented. Dual-kernel structure of System is adopted: Linux and RT-Linux are used to realize Time-sharing tasks and Real-time tasks separately. The system is divided macroscopically into two parts: Real-time part and Time-sharing part, microcosmically into three modules: Real-time Control Module, Drive Module and CNC User Module. Through the communications among them, three modules construct the whole system. Rimed Turbine Blisk was experimentalized to validate the performance of the system. The process and the results implied that the system is Real-time, stable and reliable.
Study on Computer-Aided Optimizing Milling Parameters of Numerical Control Machine
Authors: Zhao Yu Xia , Xu Hong Hai , Gao De Wen
Published: October 2009

In this paper, the modern theory of milling and the optimization technique are applied to the establishment of the mathematical model of face milling to obtain the optimum face milling parameters, in which the highest productivity is the optimizing objective，and many constraints are taking into consideration．The optimization is programmed based on the complex form method and castigatory function method．And a optimization system is established, the system which is composed of optimizing calculation module, special milling parameters database and man-machine interface．And it is programmed by adopting Visual Basic．The NC milling example is optimized，the validity and practicability of optimizing mathematic model is proved，and the base of the optimization of the NC machining process is established．
A Method for Numerical Solutions to Problems with Pipes under Unknown Forces and Constraint Conditions
Authors: Shi Dong Yan , Xia Ku Ang , Lin Hua Chun
Published: October 2009

For the solutions to engineering equipment with pipes, unknown forces and unclear constraint conditions on the pipes result in the analysis limitation due to the high temperature and fluid pressure to pipes. In this paper, a new method for determining the loads is established to problems with many pipes. In the method, based on the combination of FEM and Successive Approximation Approach, pipes forces on the equipment are analyzed. By the analysis of suitable forces, the relationship between forces and stress can be obtained. The cycling process of “loading-solving-determining-adjusting” is carried out to approaching destinations based on hundreds of numerical results. Moreover, an evaluation scheme is built to evaluate groups of forces and guarantee equipment to work normally under some certain forces. The constraint condition from groups of forces can be also confirmed. A case study gave the verification of the method.
Research on Multi-Actuators Speed Control Methods in Large-Scale Vessel
Authors: Wan Hui Xiong , Huang Hui , Huang Hai Bo
Published: October 2009

For multi-actuators speed control system driven by single pump, several effective control methods have been proposed, such as flow feedback control, etc. These methods are effective only to the engineering equipment with fewer actuators. As for large vessels with more than ten actuators required for speed control, using traditional control methods will result in that costs much, the structure of the hydraulic system is very complicated, even unable to realize. In order to meet the coordinate action of many actuators, two ways based on throttle control and pressure compensation control are introduced in this paper. The research results based on the theoretical analysis of speed control error and adaptability, simulation research and experimental confirmation indicate that the throttle control method is limited by the number of actuators, load size and the speed error, but the pressure compensation control method is helpful to enhance rationality and the coordination of flow distribution between various actuators.
Microstructure and Micro Mechanical Property of Part Formed by GMAW Surfacing Rapid Prototyping
Authors: Zhu Sheng , Li Chao , Shen Can Duo , Liu Jian
Published: October 2009

The self-made metal cored wires with Fe-Si-Mn-Ti-B microalloyed series were adopted to directly form a part by gas metal arc welding (GMAW) surfacing rapid prototyping technology. The microstructure and microhardness of the part are both investigated. Its continuous metallographic microstructure along and vertical to the deposition direction shows layered characteristic, due to the special thermal cycles and cooling conditions. The microhardness values of intermediate sections of the part are much higher and stabler than those of surface sections. It is necessary to deposit a wear-resistant metal layer for enhancing the surface abradability. Among the microstructures of the part, the average nanohardness of acicular ferrite is 1.28 times than that of massive ferrite, but their Young’s modulus values are almost equivalent, which indicates acicular ferrite possesses excellent mechanical property. Therefore, achieving acicular ferrite microstructures is an appropriate means to enhance the combination property of the formed parts.
The Impact of Rising Ni and V Impurity Levels in Smelter Grade Aluminium and Potential Control Strategies
Authors: Grandfield John F. , Taylor John A.
Published: October 2009

The technology for controlling smelter metal impurities post reduction has steadily improved. For example, control of sodium has seen the reduction and, in some plants, the elimination of chlorine gas from the casthouse. However, changes in the purity of cell feed materials such as anodes are giving rise to new challenges in impurity control; vanadium and nickel levels are an emerging problem. This paper briefly reviews the important impurities and their effects on downstream casting, forming and final application properties. Particular emphasis is given to nickel and vanadium. Strategies for controlling these impurities are also discussed and areas where new technology is needed are also highlighted. In some cases it is not known what the tolerable limits of impurities are. There are a plethora of metal refining techniques used in the extraction of other metals which could be investigated for the control of impurities in smelter grade aluminium.
Downstream Considerations of Fusion Clad Casting
Authors: Wagstaff Robert B. , Bischoff Todd F. , Sinden Dave
Published: October 2009

Fusion casting has been commercially available for over 3 years. Although there are many interesting points to casting, there are several downstream considerations such as scalping, preheat and rolling. Quality rolled clad sheet needs to have a consistent clad thickness. Appropriately varying the geometry of the clad layer during the transient portions of casting results in consistent clad thickness from head to butt. Controlling the edge wipe during rolling off does the same from edge to edge. The severity of edge wipe off can be predicted from relative flow stresses at rolling temperatures and guides the choice of alloy combinations.
Grain Refinement and Hot Tearing of Aluminium Alloys - How to Optimise and Minimise
Authors: Easton Mark , StJohn David H. , Sweet Lisa
Published: October 2009

Grain refinement and hot tearing are important key factors affecting the quality of castings. There have been substantial advances in the understanding of both of these phenomena over the last two decades. The paper discusses strategies for obtaining the lowest cost grain refiner addition and provides an explanation for how the refinement of equiaxed grains leads to a reduction in hot tear susceptibility. However, it also provides a warning that adding more grain refiner may not be better for reducing hot tear susceptibility. Alloy factors affecting hot tearing are also discussed. Finally, a list of six key considerations is provided to help casthouse and foundry engineers when trying to optimise grain refinement and reduce hot tearing.
Adaptive Composite Materials with Novel Architectures
Authors: Silvain Jean François , Denis-Lutard Valérie , Geffroy Pierre Marie , Heintz Jean Marc
Published: October 2009

Today, there is a strong push to improve the thermal management of electronic components in order to increase the performance and the reliability of electronic devices. Up to now, most of the heat sinks are mainly made of Copper that presents a good thermal conductivity (TC) but a coefficient of thermal expansion (CTE) much higher than the ceramic of the DBC (direct bonding Copper). It induces interfacial thermal stresses and indeed it decreases the reliability of the global electronic system. Therefore, there is a strong need for the development of novel heat dissipation material having low CTE combined with high TC. Carbon fibres reinforced copper matrix offers a good compromise between thermo mechanical properties (i.e. CTE) and medium TC. In order to increase surface TC, pure Copper can be added on the top surface and/or on the bottom one of the composite heat sink playing the role of heat spreader for hot spots linked with the Si components. The fabrication technique of these materials is based on powder metallurgy technique. The thermal properties of adaptive materials, TC and CTE, have been measured for different Copper thicknesses and architectures ([C/Cu], [Cu – C/Cu] and [Cu – C/Cu – Cu]). Simulation of the TC and CTE have been performed and compared to the experimental results.
Thermal Stress Analysis of an FGM Cylinder under the Effect of Convection and Radially Varying Temperature Distribution
Authors: Topal Serra , Gulgec Mufit
Published: October 2009

The plane strain problem for a functionally graded solid cylinder with thermal energy generation under the effect of convective heat transfer is considered. In previous studies on FGM cylinders in the literature, the modulus of elasticity, the thermal conductivity and the thermal expansion coefficient are represented by using either exponential or power functions. However, this study considers different functions for these material properties, which results in a more realistic representation of the problem. The stress and strain components are evaluated analytically and their dependencies on the radially varying material parameters are presented at the elastic state. Critical values of the volumetric thermal energy generation evaluated for a homogeneous solid cylinder and for an FGM cylinder are compared by using the Tresca’s Yield Criterion. Numerical results are generated by considering a W/Cu FGM solid cylinder which has potential applications as an International Thermonuclear Experimental Reactor (ITER) component.
Terahertz Wave Properties of Ceramic Photonic Crystals with Graded Structure Fabricated by Using Micro-Stereolithography
Authors: Kirihara Soshu , Niki Toshiki , Kaneko Masaru
Published: October 2009

Fabrication and terahertz wave properties of alumina micro photonic crystals with a diamond structure were investigated. The three-dimensional diamond structure was designed on a computer using 3D-CAD software. Acrylic diamond structures with alumina particles dispersion were formed by using micro-stereolithography. Fabricated precursors were dewaxed and sintered in the air. The electromagnetic wave properties were measured by terahertz time-domain spectroscopy. A complete photonic band gap was observed at the frequency range from 0.40 to 0.47 THz, and showed good agreement with the simulation results calculated by the plane wave expansion method. Moreover, a localized mode was obtained by introducing a plane defect between twinned diamond structures. The one-way transmission of the electromagnetic wave was realized by using this twinned photonic crystal with the graded diamond structure. They corresponded to the simulation by the transmission line modeling (TLM) method.
Computational Evaluation of Effective Conductivity of Particulate Composites with Imperfect Interfaces
Authors: Zhang M. , Zhai Peng Cheng , Zhang Qing Jie
Published: October 2009

This paper is aimed to numerically evaluate the effective thermal conductivity of randomly distributed spherical particle composite with imperfect interface between the constituents. A numerical homogenization technique based on the finite element method (FEM) with representative volume element (RVE) was used to evaluate the effective properties with periodic boundary conditions. Modified random sequential adsorption algorithm (RSA) is applied to generate the three dimensional RVE models of randomly distributed spheres of identical size with the volume fractions up to 50%. Several investigations have been conducted to estimate the influence of the imperfect interfaces on the effective conductivity of particulate composite. Numerical results reveal that for the given composite, due to the existence of an interfacial thermal barrier resistance, the effective thermal conductivity depends not only on the volume fractions of the particle but on the particle size.
Investigation on the Effect of Test Parameters on Small Punch Creep Tests by Finite Element Method
Authors: Wang Jian Ping , Chen Gang , Zhai Peng Cheng , Zhang Qing Jie
Published: October 2009

The small punch creep (SP-C) test technique is a new method which is applied to evaluate the high temperature creep properties of materials by using miniature specimen. In the present paper, the Finite Element Method (FEM) is employed to simulate the SP-C test in order to investigate the effects of test parameters on testing results of the SP-C test. In this attempt, we perform systematic numerical simulations of SP-C tests by changing friction coefficient, specimen thickness, the diameter of punch ball and the inner diameter of lower die, and discuss the effects of the variation of test parameters on test results in detail. The resulting regression equations for assessing the effects of testing parameters on test results are obtained. It is found that the test results are influenced significantly by the specimen thickness, the diameter of punch ball and the inner diameter of lower die. However, the effects of friction coefficient on the results of the SP-C test can be neglected.