bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of Idling Stop Technology for Servo Motors in Machine Tool Operations to Reduce Electric Power Consumption
Authors: Nagawaki Tomohiro , Hirogaki Toshiki , Aoyama Eiichhi , Ogawa Keiji
Published: May 2014

Recently, with regard to global warming energy shortage, the saving energy has become a global issue. The demand for variety, variable production, high speed, high accuracy, and complex processing in the manufacturing fields has been emerged. Furthermore, automatic extinction of computer numerical control (CNC) screens and automatically hold of oil pressure pump in idling has been raise to do on research. On the contrary, there are few reports dealing with reducing power consumption based on existing machining tools system. The method presented in this report can be applied to various size and weight of machining tools. The experimental result of standby power and minimum power with emergency stop circuit of various machining tools is discussed in this research work. To expand the stage of the proposed method, a brand new system is developed. As a result, power consumption of a machining tool with the phase of idling can be effectively reduced through emergency stop circuit. By activating emergency stop circuit, power consumption can be equalized with the condition of main power-ON only. The standby electric power increases along with increasing weight of machining tools. Through the proposed original system, it is possible to set switching of servo ON and OFF to each section. Consequently, the methodology would be applied into many fields of precision processing.
Finite Element Modeling of the Effect of Tool Rake Angle on Cutting Force and Tool Temperature during High Speed Machining of AISI 1045 Steel
Authors: Sulaiman Sreenivasan , Mohd Ariffin Mohd Khairol Anuar , Roshan A.
Published: May 2014

A finite element model (FEM) of an orthogonal metal-cutting process is used to study the influence of tool rake angle on the cutting force and tool temperature. The model involves Johnson-Cook material model and Coulomb’s friction law. A tool rake angle ranging from 0° to 20° and a cutting speed ranging from 300 to 600 m/min were considered in this simulation. The results of this simulation work are consistent optimum tool rake angle for high speed machining (HSM) of AISI 1045 medium carbon steel. It was observed that there was a suitable rake angle between 10° and 18° for cutting speeds of 300 and 433 m/min where cutting force and temperature were lowest. However, there was not optimum rake angle for cutting speeds of 550 and 600 m/min. This paper can contribute in optimization of cutting tool for metal cutting process.
Temperature Distribution of Micro Milling Process due to Uncut Chip Thickness
Authors: Baharudin B.T.H.T. , Ng Kooi Pin , Sulaiman S. , Samin R. , Ismail M.S
Published: May 2014

A simplified model for micro milling process is presented, as well as results on temperature on tool and work piece. The purpose is to investigate on finite element modelling of two flute micro end milling process of titanium alloy, Ti6Al4V with prediction of temperature distribution. ABAQUS/Explicit has been chosen as solver for the analysis. A thermo-mechanical analysis was performed. First model was created by selecting medium carbon steel, AISI1045, as workpiece material for model validation purpose. Second model was created by modifying the workpiece material from AISI1045 to Ti6Al4V. The model consists of two parts which are tungsten carbide micro tool and workpiece. Johnson-Cook law model has been applied as material constitutive properties for both materials due to its severe plastic deformation occur during machining. Prediction on forces was obtained during the analysis. Model validation was done by comparing results published by Woon et al. in 2008. The results showed a good agreement in cutting force. Once this was proved, the same model was then modified to simulate finite element analysis in micro milling of Ti6Al4V. Prediction of temperature distribution of micro end mill of Ti6Al4V was done in relation of different undeformed chip thickness. The findings showed that temperature increases as undeformed chip thickness increases. Temperature distribution of Ti6Al4V and AISI1045 under same machining conditions was compared. Results showed that the highest temperature was concentrated at tool edge for Ti6Al4V.
Effect of Optical Properties Characteristic Polymethylmethacrylate Using UV Laser Direct-Structuring
Authors: Chung Chien Kai , Hsaio Wen Tse , Tseng Shih Feng , Huang Kuo Cheng , Chen Ming Fei
Published: May 2014

Polymethylmethacrylate (PMMA) material has excellent characteristics, such as being light weight, low cost, ease of machining, and optical quality, which are useful in numerous applications such as backlit LCD display panels, lens optics, and other photoelectric fields. Laser machining of polymerization material results in a superior machining quality, high accuracy, high speed, and high reproducibility, produces a small variety of products, reduces mold costs, and enables the rapid manufacture of products based on complex graphics by processing different depths and widths of the 3D structure. This paper presents the fabrication of symmetrical array microstructures on PMMA material by using a UV laser system. The PMMA material dimensions and thickness were 20 x 20 mm and 1 mm, respectively. Regarding the machining quality, the laser pulse energy, pulse repetition frequency, and fill spacing were adjusted. For the experiments, a semiconductor laser source (635 nm/5 mW/TEM00) and a beam profiler were used to measure the characteristics of a laser beam passing through the microstructures. The microstructure pitches and morphologies also affected the light uniformity. After laser machining, the surface morphology and the light transmittance were measured using a spectrophotometer.
An Analytical Model for Deformation Path Design in Multistage Incremental Sheet Forming Process
Authors: Liu Zhao Bing , Li Yan Le , Daniel W.J.T. Bill , Meehan Paul
Published: May 2014

Incremental sheet forming (ISF) is a new promising technology due to its flexibility and low-cost tooling properties compared with conventional forming processes. However, a common technical problem encountered in ISF is non-uniform thickness variation of formed parts, particularly excessive thinning on severely sloped regions, which may lead to the part fracture and limit the process formability. Design of multistage deformation paths (intermediate shapes or preforms) before the final part is a desirable and practical way to control the material flow in order to obtain more uniform thickness distribution and avoid forming failure. Based on the shear deformation and the strain compensation idea, an analytical model for designing multistage deformation paths and predicting the thickness strain distribution is proposed. The feasibility of the proposed model is validated by the finite element analysis (FEA) and experimental tests in terms of the comparison of prediction, simulation and experimental results on the thickness strain distribution and the process formability.
Forming Limits of Several High-Strength Steel Sheets under Proportional/Non-Proportional Deformation Paths
Authors: Hino Ryutaro , Yasuhara Satoki , Fujii Yutaka , Hirahara Atsushi , Yoshida Fusahito
Published: May 2014

Forming limits of several high-strength steel (HSS) sheets under non-proportional deformation paths were examined experimentally and predicted analytically. Forming limit curves (FLCs) for 590MPa, 780MPa and 980MPa grade HSS sheets were obtained by performing stretch forming tests under proportional deformation and two types of non-proportional deformation. The experimental results showed strong path-dependent characteristics of FLCs of HSS sheets. Forming limits of equi-biaxially prestrained HSS sheets became markedly lower compared to the original FLCs under proportional deformation, while forming limits of uniaxially prestrained HSS sheets became partially higher than the original FLCs. It was confirmed that Marciniak-Kuczyński type analysis gave reasonably good predictions of forming limits under non-proportional deformation paths. Especially forming limit predictions of equi-biaxially-prestrained sheets showed good agreement with the corresponding experimental results.
A Study of Hole Flanging-Upsetting Process
Authors: Yan Guang Xu , Wang Xin Yun , Deng Lei , Jin Jun Song
Published: May 2014

A combined process of hole flanging and flange upsetting was proposed. Both elastic-plastic FEM and experiments were employed to analyze the process. A 2mm thick 08AL sheet with 120mm outer diameter and 24.6mm center hole diameter was used as the blank. The effect of the Rf and the Rc values on the flanging quality were analyzed, where Rf was defined as the ratio of the die fillet size to the workpiece thickness t and Rcwas defined as the ratio of the clearance C to the workpiece thickness t. Also the effect of Rf and Rc on upsetting ratio Ru which was defined as the ratio of thickness before and after upsetting were studied. The finite element results were validated by experimental results. Also a 2mm thick flange without thinning and defects was gained in a reasonable range of Rc and a certain value of Rf.
Comparison of Cast and Extruded Stock for the Forging of AA6082 Alloy Suspension Parts
Authors: Birol Yucel , Ilgaz Onur , Akdi Seracettin , Unuvar Erdem
Published: May 2014

High-precision near-net shape parts with excellent surface qualities can be produced with the forging process with a minimum of finishing operations thanks to the good formability of aluminium alloys. There has been a rapid increase in the use of aluminium forgings predominantly in the automotive industry, where weight savings for reduced fuel consumption and exhaust emissions is mandated by legislation. Aluminium forgings provide, in addition to low weight, high strength, good corrosion resistance and a fibrous grain structure to improve fatigue resistance. Typical commercial forging stock is the round bars produced by the extrusion of cast billets. An alternative process route that has received increasing attention in recent years is the casting of forging stock by a horizontal direct chill casting technique to make smaller billets without the need for extrusion to reduce their diameter. The anisotropy imparted to the forging stock via extrusion, often regarded as useful for the forging, is certainly missing in the former. However, cast stock has been reported to be more resistant to the formation of coarse surface grains than the extruded counterpart. The present work was undertaken to compare the casting and extrusion routes for the manufacture of 6082 alloy forging stock.
A Structure and Morphology of Nanocomposites Composed of Carbon Nanotubes with a Varying Fraction of Platinum Nanoparticles
Authors: Dobrzańska-Danikiewicz Anna Danuta , Pawlyta Mirosława , Łukowiec Dariusz
Published: May 2014

A structure of nanocomposite materials consisting of carbon nanotubes with a varying fraction of platinum nanoparticles (5, 10 and 20 wt %) is compared in the paper. High-quality CNTs obtained in the CVD process, 100-200 mm long with a standard deviation of below 20% and with a diameter of 10-20 nm, with a standard deviation of below 30%, were used in the research. Raw CNTs did not contain metallic impurities or amorphous carbon deposits. An indirect method of bonding the earlier produced platinum nanoparticles to the surface of functionalised carbon nanotubes was employed to deposit platinum nanoparticles onto the surface of carbon nanotubes. A full array of changes in the loading of carbon nanotubes’ surface with platinum nanoparticles was achieved as a result of the experiments performed, starting with homogenous deposition to the clearly developed large agglomerations of platinum nanoparticles. The studies carried out using scanning electron microscopy, transmission electron microscopy, scanning transmission electron microscopy and X-ray structural analysis have confirmed differences in the morphology, homogeneity and density of coating the carbon nanotubes’ surface with variedly concentrated platinum nanoparticles. Differences were also revealed in the structure of the newly formed nanocomposites. A nanocomposite with a 5% fraction of platinum nanoparticles demonstrates the best structure-related properties for the materials obtained.
Experimental Study and Efficient Prediction on Forming Forces in Incremental Sheet Forming
Authors: Li Yan Le , Liu Zhao Bing , Lu Hai Bo , Daniel W.J.T. Bill , Meehan Paul A.
Published: May 2014

Incremental sheet forming (ISF) is a promising forming process in which complex 3D shapes are formed from a sheet of metal using a simple moving tool. The efficient prediction of contact forces in ISF is desirable to monitor the forming process, prevent failure, and implement on-line control and process optimization. However, traditional Finite Element (FE) simulation used for force prediction is significantly time-consuming for complex products. The purpose of this study is to investigate the ISF force prediction and characteristics under different forming conditions and build a potential efficient model.
In the present work, forces during the cone forming process with different wall angles and step down sizes were recorded and compared. Different force trends were identified and discussed with reference to bending and strain hardening mechanics. Influences of different parameters on designated formability were also qualified which should benefit the product design process. An efficient predictive model based on upper-bound approach was applied for force prediction in this case. Predicted tangential forces were then compared with the experimental results showing relatively good agreement. The limits of the proposed model were also identified and the potential of future improvements were suggested.
On Flow Layer Uniformity in the Co-Extrusion of Polymer Multilayer Film
Authors: Tzeng Guo Chiuan , Chen Ren Haw
Published: May 2014

In the multilayer co-extrusion process, two or more materials are simultaneously brought together and layered in a single extrusion process. When co-extruding two polymers with different rheological properties, uniformity control of the flow layer at and downstream of the confluence is vital for the quality of multilayered film products. This work aimed to investigate the effects of viscosity and elasticity of the co-extruding polymers on the layer uniformity at the confluence. We conducted a PC/PMMA/PC three-layer film co-extrusion experiment to observe the flow of polymer melts at the confluence in the die. The thickness variation of each layer along the flow was recorded through a viewing window structured on the die wall using a camera. In addition, the flow and stress field analyses of PC/PMMA/PC co-extrusion were performed using POLYFLOW software. The research results demonstrated that oscillation of flow velocity in machine direction along the PC/PMMA interface accompanying a wavy distribution of layer thickness along the flow may occur due to the differences of viscosity and elasticity between the PC and PMMA. Although slipping may occur at the PC/PMMA interface, which reduces the shear stress between the PC and the PMMA layer boundaries, the shear stress distribution crossing the PC/PMMA interface is not continuous. The imbalance of the shear stresses along the adjacent PC and PMMA boundaries expands with the extrusion rate, which can cause the interface to distort. To avoid the occurrence of interfacial instability, the length of die channel downstream the confluence must be shortened as much as possible, and the extrusion rate must be lowered.
Effect of Interference-Fit on Fatigue Life for Composite Lap Joints
Authors: Xue Hong Qian , Tao Qian , Bayraktar Emin
Published: May 2014

The aim of this study is to examine the effect of the clearance and interference-fit on the fatigue life of composite lap joints in double shear, 3D finite element simulations have been performed to obtain stress (or strain) distributions around the hole due to interference fit using FEM package, Non-linear contact analyses are performed to examine the effects of the clearance and interference for titanium and composite lap joint. Fatigue tests were conducted for the titanium and composite lap joints with clearance fit and interference fit with 0.5, 1, and 1.5% nominal interference fit levels at different cyclic loads. The results shows that interference fit increases fatigue life compared to clearance fit specimens, the titanium and composite lap joint with 1% interference fit level has the better fatigue life.
Development of Looper Shape Meter and Verification Test Results in Hot Rolling
Authors: Furumoto Hideaki , Kinose Ryohei , Maniwa Shuji , Takao Owada , Hayashi Kanji , Kanemori Shinya , Sueda Shigeki
Published: May 2014

The harder and thinner strips, such as high strength steel and so on, have been needed to be rolled. When the rolled strip becomes thinner and harder, the unstable state rolling and tail end pinching might occur and so the strip shape measurement during rolling is strongly required under the condition that tension is applied to the strip. Visual-type shape meter, which has been already used, could not measure the strip shape when tension is applied to the strip. Looper Shape Meter, hereinafter referred as LSM, has been developed which could measure the strip shape under the tension. LSM is installed between mill stands and consists of 7 segment rolls along the width direction and a segment roll has two torque meters. LSM could accurately measure the tension distribution along the width direction without hysteresis and is protected with purge air and internal cooling system against severe environment in hot rolling. In order to verify the performance of LSM, the verification test was carried out in laboratory and production line. As a result, enough durability and good results of measured strip shape are obtained. LSM is easily replaced with existing conventional looper and it is expected that LSM contributes to the stable rolling and improve the productivity of rolling.
Effect of Temperature on Cyclic Behavior of AZ31 Mg Alloy Sheet
Authors: Katahira Takashi , Hosokawa Syohei , Naka Tetsuo , Kohzu Masahide , Adachi Hiroki , Yoshida Fusahito
Published: May 2014

Magnesium alloy sheets have a potential to be widely used in many fields of industry due to their excellent lightweight property. Although magnesium alloys have low ductility at the room temperature due to their hexagonal close-packed structure, their formability can be improved at elevated temperatures. Therefore, warm press-forming of magnesium alloy sheets is an attractive technology. The objective of the present work is to investigate the cyclic plasticity behavior of an AZ31 sheet at elevated temperatures by performing cyclic tension-compression experiments. The cyclic deformation mechanism is examined by measuring the crystallographic orientation distributions by means of X-ray diffraction method at each stage of the cyclic deformation. The present findings are summarized as follows: (1) Stress-strain responses of an AZ31 sheet were investigated at various temperatures (R.T, 100, 150 and 200°C) at strain rates of 0.001, 0.01 and 0.05 s-1. The flow stresses were insensitive to the strain rate at the room temperature, however the strain rate dependency of the flow stress becomes dominant at elevated temperatures of over 100 °C.(2) Cyclic plasticity behavior of the sheet at various elevated temperatures (R.T, 100, 150 and 200 °C) at strain rates of 0.001, 0.01 and 0.05 s-1 were investigated by performing warm in-plane cyclic compression-tension test. Similarly to the uniaxial tension test, apparent temperature and strain rate dependencies of the flow stress were observed at temperatures of over 100 °C. (3) At the room temperature an unusual cyclic stress-strain curve, which is very different from that of bcc and fcc metals, was observed. From the texture measurement it was found that such a specific stress-strain characteristic is due to its twinning and detwinning deformation mechanism.(4) In contrast, at an elevated temperature of 200 °C, the usual cyclic stress-strain response, which is similar to one appearing in most of metallic materials, was observed. This is because the major deformation mechanism at an elevated temperature is the slip, rather than twinning/detwinning, since the CRSS decreases drastically with increasing temperature.
Development of a Self-Propelled Multi-Jet Polishing Tool for Ultra Precision Polishing
Authors: Tsegaw Assefa Asmare , Shiou Fang Jung
Published: May 2014

As the needs of optical glasses are on the rise, the precision on shape, form, surface qualities and the scaling down of sizes are rising, too. The standards and surface finish of reference mirrors used in measuring appliances are crucial; hence, enhancement of the surface finish is indispensable in manufacturing industries. This paper proposes a self-propelled multi jet polishing technique for ultra precision polishing process in which bladeless Tesla turbine was used as a prime mover. The turbine is characterized by high swirling velocity at the outlet; therefore, high kinetic energy in the course of away from the turbine was used as polishing energy. Simulation of the flow of the field of turbine blades using computational fluid dynamics software (CFD) has also been presented. With a newly designed and manufactured polishing tool, this paper investigates the optimal polishing parameters for surface roughness improvement of crown optical glasses using Taguchis experimental approach; signal-to-nose (S/N) ratio and ANOVA analysis was also carried out to determine the effect of main factors on the surface roughness. Consequently, a 2.5μm size of Al2O3 abrasive, 10wt% abrasive concentration, 80rpm of polishing head, 6 numbers of nozzles, 6 kg/cm2 of pressure, and 45min. of polishing time have been found to be the optimal parameters. It was observed that about 94.44% improvements on surface roughness; Ra, from 0.360μm to 0.020μm has been achieved using the optimal parameters. In addition to this; angular speed of polishing head, pressure and polishing time were found to have significant effect on surface roughness improvement.
Surface Roughness Measurements of a Narrow Borehole — Development of Stylus with Cylindrical Mirror and Lensed Fiber
Authors: Okuyama Eiki , Yoshinari Wataru , Suzuki Yuichi , Yoshida Riku , Yoshida Ichiro , Iwakata Masashi
Published: May 2014

In various industrial fields, it is frequently necessary to measure surface roughness in confined spaces such as boreholes and grooves. However, using a small stylus, the surface roughness of a narrow borehole can be directly measured only a few millimeters from its end; alternatively, destructive measurements must be performed. This major disadvantage of conventional stylus-based surface profilometers is mainly due to an inductive pick-up that is connected to the stylus used to detect the surface roughness. In this paper, we propose a novel surface roughness measurement sensor. To make the surface roughness sensor small, we used a stylus with a cylindrical mirror and a lensed fiber instead of a conventional inductive pick-up. The proposed sensor converts the signal obtained by measuring the surface roughness of a borehole into an optical signal, which is transferred outside the borehole by an optical fiber. Experimental results demonstrate that this system has a measurement range of 8 μm and a sensitivity of 19 nm. Surface profiles were measured by the proposed sensor and by a conventional surface profiler and the results were found to be very similar.
The Numerical Research of Drag Reduction over Bionic Fluctuation-Adaptive Non-Smooth Surface
Authors: Hu Ya Lun , Zhu Meng Lei , Xiao Jun , Wang Xing Zhen , Xu Zhong
Published: May 2014

This paper does some research about the drag reduction mechanism of dolphins soft and adaptive skin in view of bionics. The study shows that dolphin skin is very sensitive to pressure changed by external flow field, and can do a wave-like movement with the uneven pressure, resulting in a traveling wave of the non-smooth surface which reducing frictional resistance on the wall surface in the turbulent flow field. Based on Karman vortex street and momentum theory, we described the relationship between the geometry of traveling wave and the drag reduction efficiency, and with the help of numerical simulations of traveling wave surface using RNG k-ε model and a series of experiments, we get the friction coefficient near the wall boundary, the turbulence intensity, and the distribution of the velocity field. The results show that, compared with smooth surface, the non-smooth surface of traveling wave reduces frictional resistance of the adhesion surface owing to changing the fluid flow state. Moreover, the non-smooth surface of traveling wave shows significant drag reduction effect at the stream velocity about 6 m / s.
A Study on the Warm Forging-Flaring Process of Brass Tube
Authors: Liu Chun Ho , Wang A Cheng , Lee Cheng Han , Huang You Min
Published: May 2014

At present, quite a lot of enterprises, small or medium-sized, are engaged in developing the various necessaries of livelihood. And, the forming processes are generally adopted for the methods of parts manufacture. Though various forming technology progress rather well, but the warm working process often cannot obtain fine finished products in the process of manufacturing. The warm working process still needs more adequate techniques. This study is focused on the analyzing of the warm forging-flaring process of brass tube, and the improving of the die design and the working procedures. In this paper, two sets of forging and flaring die are designed for experimental works. The results of simulation are compared with the experiments, the formability of brass tube showed a good agreement. Therefore, we suggest a multi-pass of forging process instead of single-pass process. The stress distributions and loading history in forming processes are also assessed in details. The method used in this study is available in the relative warm forming processes and die design. It is helpful to increase the additional value of products and promote the level of competition in manufacturing industry.
Effects of Scoring Depth, Tracking Angle, Rubbering on Bending-Moment Relaxation of Creased Paperboard
Authors: Nagasawa Shigeru , Shiga Yoshiaki , Fukuzawa Yasushi
Published: May 2014

This work deals with the time-dependent creasing characteristics of coated paperboard. The correlation between the bending strength (resistance) and time-dependent problems on the actual processing phenomenon has not been sufficiently discussed in the past. It is difficult to estimate various time-dependent responses from the initial strength of the creased part, such as the maximum bending moment and the initial gradient of bending moment. In this study, therefore, a prototype testing apparatus has been applied to investigate about the dynamic relaxation of bending moment. In order to reveal the relaxation characteristics of the bending resistance during the folding motion from an initial position up to various tracking angles, a white-coated paperboard of 0.3 mm thickness was scored with a creasing rule and a grooved counter face plate under a specified feed velocity, and then the bending test was carried out by varying the tracking angle. Through this work, the followings were obtained: (1) The relaxation of the bending moment was characterized by an exponential coefficient which was independent to the nominal shear strain and the tracking angle. (2) The relaxation depends on the rubbering condition.
Investigation of Drilling Conditions of Printed Circuit Board Based on Data Mining Method from Tool Catalog Data-Base
Authors: Haneda Hisaya , Kodama Hiroyuki , Hirogaki Toshiki , Aoyama Eiichi , Ogawa Keiji
Published: May 2014

Data-mining methods using hierarchical and non-hierarchical clustering are proposed that will help engineers determine appropriate drilling conditions. We have constructed a system that uses clustering techniques and tool catalog data to support the determination of drilling conditions for printed wiring boards (PWBs). Variable cluster analysis and the K-means method were used together to identify tool shape parameters that have a linear relationship with the drilling conditions listed in the catalogs. The response surface method and significant tool shape parameters obtained by clustering were used to derive drilling condition decision equations, which were used to determine the indicative drilling conditions for PWBs. Comparison of the conditions recommended by toolmakers demonstrated that our proposed system can be used to determine the drilling condition for PWBs. We carried out the drilling experiments in accordance with the catalog conditions and mining conditions, and estimated the board temperature around a drilled hole, the drilling forces, and the roughness of the drilled hole wall.
Prediction of Maximum Forging Load and Billet Volume Using FEM of a Near Net-Shaped Helical-Bevel Gear Forging
Authors: Yang Tung Sheng , Liang Jia Hua , Chang Jie
Published: May 2014

This study applies the finite element method (FEM) to predict maximum forging load, billet volume and effective strain in near net-shaped helical-bevel gear forging. Finite element analysis is also applied when designing the near net-shape of a helical-bevel gear, a reverse forming approach to acquire the initial dimensions of the billet based on the forward forging of the helical-bevel gear. Maximum forging load, billet volume and effective strain are determined for different process parameters, such as modules, number of teeth, helix angle and workpiece temperature of the helical bevel gear forging, using the FEM. Finally, the prediction of the power requirement and billet dimensions for the helical-bevel gear warm forging are determined.
The Development of a Cross-Flow Fan for Electronic Devices Cooling with a Focus on Laptop Computers
Authors: Li Ai Tsung , Hsu Ray Quen
Published: May 2014

The directive is to develop a new type of cross-flow fan for cooling electronic devices. First, the module is based on the 60X60X6mm fan and attempts to use several parameters to enhance the fan’s performance. The parameters considered here include blade number, angle of the blade, impeller diameter, divergent structure, and outlet area. Both numerical and experimental analyses are carried out on the cross-flow fan which was oriented horizontally. The ANSYS Fluent software is used in a 2D simulation to predict the heat transfer coefficient and the flow fields. Next, the flow and acoustic noise measurements are carried out at different parameters with the aid of AMCA and semi-anechoic chambers. The results show that when the outlet vent size is 70% of fan outside diameter the outcome is an enhanced fan performance of 12%. The optimal number of blades is 37. A block is inserted below the fan blade to improve the fan performance by 8%. The numerical and experimental values of air flow were plotted and found to be consistent. In summary, this study provides a systematic process to develop a cross-flow fan that can meet the requirements for thin and light laptop computers.
The Study on the Boltzmann Distribution of Ideal Gas under Gravitational Field by Computer Simulation
Authors: Huang Jen Ching , Cheng Fu Jen
Published: May 2014

In this paper, it based on the ideal gas conditions in the Maxwell velocity distribution and considering only the elastic collisions between gas molecules to study the distribution of gas molecules in the gravity field as a means of computer simulation. The simulation results show the process of molecular movement and distribution patterns. And it can be found that the distribution of gas molecules in the gravity field distribution is determined by the frequent collisions between molecules and it has nothing to do with the velocity and the initial position of molecules.
In addition, the simulation also reveals the Boltzmann distribution law is a statistical regularity in terms of the large number of particles. The ideal gas elastic collision simulation software can increase intuitive awareness of students on the knowledge, and to provide an effective adjunct to consolidate what they have learned.
Development of an Advanced Semi-Active Damper Using Smart Fluid
Authors: Ferdaus Mohammad Meftahul , Rashid Muhammad Mahbubur , Bhuiyan M.M.I.
Published: May 2014

In this paper an advanced semi-active damper is designed and experimentally studied to investigate and establish its behavior. A prototype Magneto-rheological fluid Damper is designed as advanced semi-active damper due to its huge advantages. Magneto-rheological fluid with improved dispersion stability is prepared here as smart fluid. The relation between force and displacement for various current has been established to develop the semi-active damper model. In this study a fuzzy tuned PID controller is opted to achieve better response for a various frequency input. The proposed MR damper can be applied to vehicle syspension system and other suspension mitigation system widely. Moreover, the identified behaviour can help in further development of MR damper technology. The characteristics obtained from of MR damper is more realistic as it is obtained from experiments.
Development and Optimization of a Low Normal Force Contact
Authors: Bhuiyan M.M.I. , Bin Alamgir Tarik , Rashid Muhammad Mahbubur
Published: May 2014

Throughout the technological advancements, electronic devices are getting high dense and less expensive in day by bay. Thus, significantly reducing the production cost is the vital issue in order to produce more competitive device with maintaining its standard in all expect. Therefore, introducing new compact contact in high-Hertz stress with low normal force (LNF) will be a key technology to achieve the future goal. In this research, it is identified that only a 5μm radial tip with 0.1N force contact provides an excellent electrical performance which is much sharper than conventional connectors. This invention gives a big hope to produce less expensive and high dense Low Normal Force contact. The contacts durability test were also successfully passed 0.30 million cycles of uses while the contact resistance were ≦50mΩ.
Mechanism of TiO2 Nanotubes Formation on the Surface of Pure Ti and Ti-6Al-4V Alloy
Authors: Dikova Tsanka D. , Hahm Myang G. , Hashim Daniel P. , Narayanan Narayanan T. , Vajtai Robert , Ajayan Pulickel M.
Published: May 2014

The present paper deals with the investigation of the mechanisms of TiO2 nanotubes formation on titanium surfaces during anodization process. The samples were made of pure Ti Grade-2 and Ti-6Al-4V alloy. They were grinded, etched with 0,5 wt. % HF acid and anodized. The anodization was done in electrolyte containing 0,5 wt. % HF acid using DC power supply with graphite electrode as cathode. The samples were investigated by SEM, EDAX and XRD analysis.
The results show two different mechanisms of formation of TiO2 nanotubes on the surfaces of both materials. During the anodization process the oxide formations, obtained on the pure Ti surface after etching, are oxidized to nanorods; the area between them is also oxidized and connects them. This thin oxide layer grows in the metal depth while the nanorods are dissolved thus forming the porous sponge-like structure which is further transformed in tubular. While on the surface of Ti-6Al-4V alloy oxide nanonuclei originate which transform their shape from nanoseed to bowl-like with clearly pronounced bottom and walls, growing in tubular structures.
The type of the material defines the surface morphology after etching. Thus obtained morphology influences on the processes running rate in different micro-regions determining origination of the titanium nanotubes on different stage as well as by different mechanism. The field-enhanced oxidation and field-enhanced dissolution are the main processes for formation of TiO2 nanotubes during anodization. In the regions with prevalent oxidation processes the TiO2 nanotubes are formed earlier while in the regions with dominant dissolution processes the TiO2 nanotubes are formed on the later stage.
New Design of Aluminium Based Composites through Combined Method of Powder Metallurgy and Thixoforming
Authors: Ferreira Lygia Maria Policarpio , Robert Maria Helena , Bayraktar Emin , Zaimova Diana
Published: May 2014

The present study deals with a new design of aluminium alloy based composites reinforced with SiC particles and Si/Al2O3 powders through combined methods of powder metallurgy and thixoforming. Moreover, recycled machining chips are used as raw material, specifically AA7075 chips generated in the aeronautical industry. The proposed method is based on forming at high temperatures a compacted mixture of metal chips and reinforcing particles, with the metal in thixotropic semi-solid condition. Composites containing different SiC weight fractions (10, 20 and 30%) were produced and had their microstructure analyzed. Mechanical properties were evaluated by means of micro-indentation tests. General results show the feasibility of producing composites by the proposed route. Products with good mechanical properties could be obtained. The process, even still not completely optimized as some improvement still must be achieved, can bring a new possibility for the production of a noble material from recycled wastes, particularly important in the high energy spending Al industries.
Research of Large-Area Electrical Discharge Machining for Insulating Si3N4 Ceramics with the Assisting Electrode Method
Authors: Hanaoka D. , Fukuzawa Y. , Yamashita K.
Published: May 2014

Generally, all insulating materials were regarded as the non machinable workpiece for the electrical discharge machining (EDM) method. About twenty years ago, many insulating ceramics turned to the machinable materials for EDM using the assisting electrode method which was proposed by our research group. The machining mechanism was already explained with the surface adhesion phenomena [1]. In this process, many unstable discharge phenomena occurred such as concentrate, short circle and long pulse. It was clarified that they generated frequently on the high electrical resistance surface. The EDMed surface became rough and uneven on the unstable discharged area. In this paper, to obtain the good and even EDMed surface on the large removal area same as small area machining for Sinking-EDM, the effects of electrode size and shape were investigated. Considering the path of discharge supply energy on the high resistivity surface, new machining method was proposed which was named as the scanning machining method, and the ability of this method for practical use was confirmed with Si3N4 insulating ceramics. Using the new proposal method, better surface roughness and the sharp corner edge shape could be machined on the large area EDMed surface.
Tensile Properties and Microstructure of Joined Vacuum Die Cast Aluminum Alloy A356 (T6) and Wrought Alloy 6061
Authors: Wang Meng , Zou Yan Da , Hu Henry , Meng Gary , Cheng Patrick , Chu Yeou Li
Published: May 2014

In the present work, fusion-joining of vacuum high pressure die cast (HPDC) aluminum alloy A356 and wrought alloy 6061 by applying Gas Metal Arc Welding (GMAW-MIG) process was investigated to understand the effect of the MIG process on the microstructure and tensile behaviors of the base joined alloys (T6 Heat treatment A356 and 6061). The microstructures of the base metal (T6 heat treatment A356 and 6061), Heat Affected Zone (HAZ) and Fusion Zone (filler metal ER4043) were analyzed by Scanning Electron Microscopy (SEM) and optical microscopy. The results of tensile testing indicated that, the ultimate tensile strength (UTS) and yield strength (YS) of V-HPDC alluminium A356 subjected to T6 thermal treatment were relatively low, compared to both wrought alloy 6061 and the filler metal (ER 4043). The microstructure analysis showed that the low strengths of T6 A356 alloy should be at least attributed to the absence of the magnesium-based intermetallic phase, coarse grain structure and the presence of porosity, which resulted from the HPDC process, MIG welding and thermal treatment.
Processing of Epoxy-Nickel Matrix Composites Reinforced with Aluminum and Waste Elastomers
Authors: Zaimova Diana , Bayraktar E. , Tan Ming Jen , Miskioglu Ibrahim
Published: May 2014

A mixture of structural functions can be accomplished using different reinforcements in epoxy-nickel matrix composites. In the frame of the common research project, mechanical and physical properties of the epoxy resin-nickel matrix composites containing extremely fin aluminum and fine waste elastomer powders were studied. A comprehensive study is given with different static and dynamic aspects as a function of composition, frequency and temperature. Two types of waste elastomeric powders were used for the reinforcement: Styrene-Butadyene Rubber SBR and Ethylene Vinyl Acetate (EVA). All of the composites were fabricated by mixing during 4h and then put in an ultrasonic dispersion for 1h. After that, a detail analyses has been carried out by means of Dynamic Mechanical Thermal Analysis (DMTA), microindentation and wear - scratch test. Dielectric properties (Permittivity (ε′)) and dielectric loss angle tangent (tan delta) were investigated using a Dielectric Thermal Analyzer (Rheometric Scientific) at three different frequencies (1 kHz, 10 kHz, 100 kHz) from room temperature up to 280°C. Wear of surface resistance measurement has been carried out by scratch test with a normal of 2.06N load with the frequency of 10Hz in two different number of cycles; 50000 and 100000. After the test, damaged zone were measured by 3D optical roughness meter to characterize damage occurred after the scratch test.
Thermo-Solutal Modelling of Microstructure Formation during Multiphase Alloy Solidification - a New Approach
Authors: Bollada Peter C. , Mullis Andrew M. , Jimack Peter K.
Published: May 2014

This paper shows how to move from a specification of free energy for the solidification of a binary alloy to the dynamical equations using the elegance of a dissipative bracket analogous to the Poisson bracket of Hamiltonian mechanics. A key new result is the derivation of the temperature equation for single-phase thermal-solutal models, which contains generalisations and extra terms which challenge standard models. We also present, for the first time, the temperature equation for thermal multi-phase field models. There are two main ingredients: one, the specification of the free energy in terms of the time and space dependent field variables: $n$-phases $\phi_i$, a concentration variable $c$, and temperature $T$; two, the specification of the dissipative bracket in terms of these variables, their gradients and a set of diffusion parameters, which may themselves depend on the field variables. The paper explains the method within this context and demonstrates its thermodynamic admissibility.
Simulation of Liquid Film Migration during Melting
Authors: Rettenmayr Markus , Kashin Oleg , Lippmann Stephanie
Published: May 2014

Melting of a single-phase polycrystalline material is known to start by the formation of liquid films at the surface and at grain boundaries. The internal liquid films are not necessarily quiescent, but can migrate to avoid/reduce supersaturation in the solid phase. The migration is discussed in the literature to be governed by coherency strains of the solid/liquid interface, by concentration gradients in the liquid or by concentration gradients in the solid phase. A phase transformation model for diffusional phase transformations considering interface thermodynamics (possible deviations from local deviations) has been put up to describe the migration of the solid/liquid (trailing) and the liquid/solid (leading) interfaces of the liquid film. New experimental results on melting in a temperature gradient in combination with simulation calculations reveal that concentration fluctuations in the liquid phase trigger the liquid film migration and determine the migration direction, until after a short time in the order of microseconds the process is governed by diffusion in the solid phase.
Control Volume Simulation of Casting Directional Solidification
Authors: Budavari Imre , Molnar Daniel
Published: May 2014

Quality demands of castings is elemental in recent years and becoming more stringent. Foundries are faced by the need to produce high quality castings, but nonetheless to produce them economically. To fulfill this demand, experimental castings, especially in case of individual production or small runs, are uneconomical. In these cases computer simulation can be the only economical tool for testing and approval. The modulus technique of Chvorinov is an applicable method to examine the local solidification process and to determine the application of chills, geometry modification and feeding. Numerically the control volume method is used to check the solidification process of large steel castings with non-uniform wall thicknesses.
Dynamic Coarsening of Austenite Dendrite in Lamellar Cast Iron Part 1 - Investigation Based on Interrupted Solidification
Authors: Diószegi Attila , Lora Rubén , Fourlakidis Vasilios
Published: May 2014

Dynamic coarsening of austenite dendrite in lamellar cast iron has been studied for a hypoeutectic alloy. The common morphological parameter to characterize dynamic coarsening, secondary dendrite arm space has been replaced by the Modulus of primary dendrite ( MPD ) and the Hydraulic diameter of the interdendritic space ( DHydIP ) to interpret the dynamic coarsening with respect to the local solidification time. The obtained results demonstrate the coarsening process of both the solid and liquid phase. The interdendritic space is increasing as the contact time between the solid and liquid phase increases. The ratio between the DHydIP/MPD is strongly dependent on the precipitated fraction primary austenite indicating clearly the morphology variation during coarsening. The interrupted solidification method demonstrate that the observed coarsening process is not only a combination of the increasing fraction precipitated solid phase and the rearrangement of the solid liquid interphase curvature but the volume change due to density variation is also contribute to the coarsening process. Keywords: dendrite morphology, hydraulic diameter, interdendritic space, gray iron.
Dynamic Coarsening of Austenite Dendrite in Lamellar Cast Iron Part 2 - The Influence of Carbon Composition
Authors: Fourlakidis Vasilios , Lora Rubén , Diószegi Attila
Published: May 2014

Investigation of dynamic coarsening in lamellar cast iron is extended over a wide interval ranging from hypoeutectic to eutectic composition. The dendrite morphology is defined on as-cast samples produced under various cooling rates. The as-cast morphology is considered being close to the one at the end of solidification. The obtained relations describing the coarsening process as a function of local solidification time and fraction austenite are compared to results obtained from interrupted solidification experiments. By using the Modulus of primary dendrite (MPD) and the Hydraulic diameter of the interdendritic space (DHydIP) become possible to characterize the coarseness of a wide range of lamellar cast irons solidified under various cooling rates.