bluuebunny/crossref_metadata_2025 huggingface dataset:
Heat Flux Measurement Method of Two-Phase Flow in SRM
Authors: Zhang Xiang Yu , He Guo Qiang , Liu Pei Jin , Li Jiang
Published: February 2012

Accurate information on heat transfer data of combustion products in the solid rocket motor chamber is a crucial prerequisite for the engine thermal protection. A measurement technique was well developed to acquire steady-state heat flux data of two-phase flow and was used successfully in the hostile environment. Experimental heat flux measurement has been obtained with an innovative designed instrument by simulating the flow field of complex charging configuration. The total heat flux of combustion products in the chamber was brought away by the coolant and calculated by its enthalpy rise in this device. The data could be used to analyze the heat transfer phenomena in SRMs and provide boundary condition for establishing insulation erosion model.
Cutting Force Analysis of Large Branch Crusher Based on the Finite Element
Authors: Yu Sheng Tong , Yang Chun Mei , Ren Chang Qing , Luo Ge
Published: February 2012

At present, our country has stepped up efforts to develop biomass power generation. However, due to the mill not in-depth study of cutting forces and factors in the design of branches crusher which led to the branches crusher can not meet domestic branches of biomass power generation’s demand to raw materials. In the article, the cutting force of the branches grinding has been studied based on BX218 branches crusher. The formula for calculating the cutting force has been deduced. The factors that affect the cutting force have been identified. Finally, ANSYS finite element analysis carried out on the Flying, which is effected by the cutting force.
CFD Analysis of Oscillating Airfoil during Pitch Cycle
Authors: Kamran Ahmad , Wu Zhi Gang , Amjad Sohail Muhammad
Published: February 2012

This research paper presents the CFD analysis of oscillating airfoil during pitch cycle. Unsteady subsonic flow is simulated for pitching airfoil at Mach number 0.283 and Reynolds number 3.45 millions. Turbulent effects are also considered for this study by using K-ω SST turbulent model. Two-dimensional unsteady compressible Navier-Stokes code including two-equation turbulence model and PISO pressure velocity coupling is used. Pressure based implicit solver with first order implicit unsteady formulation is used. The simulated pitch cycle results are compared with the available experimental data.
Investigation of Hyperbranced Polyesters with Different Generation and their Application in Waterborne Polyurethanes
Authors: Yang Dong Ya , Han Li , Zhang Han Qing , Qiu Feng Xian
Published: February 2012

The 1st, 2nd and 3rd generations of hydroxyl-terminated hyperbranched polyesters (HBPE-1, HBPE-2, and HBPE-3) were synthesized. A3rd generation hyperbranched polyester (HBPE-3) was used as original crosslinking agent to prepared hyperbranched waterborne polyurethane dispersions (HPU). FTIR spectra confirmed that this reaction really took place. The experimental data indicated that, compared with the linear one, the hyperbranched HPU aqueous dispersions exhibited lower viscosity, and larger particle size. For the hyperbranched HPU films, mechanical properties were obviously enhanced.
Study on the Group Settling Velocity of Non-Viscous Solid Particle
Authors: Zhang Yao Zhe , Wang Shu , Zhu Jin Long
Published: February 2012

Based on the view of relative movement, the group settlement was considered as a movement of current moving up in the suspended particle layer. The expressions of Reynolds number and drag coefficient were set up by the analysis of dimension and stress of dynamic equilibrium state. The theoretic formulae on group settlement of uniform sediment in the laminar region and turbulent region are proposed. It is verified by measured data, and shown that the calculated value by the theoretic formula and measured value agree with each other fairly well.
Nonlinear Analysis of Large Deflection of Elastically-Bossed Sensor Plate under Initial Tension
Authors: Chen Chun Fu , Gao Nai Di
Published: February 2012

The nonlinear problem of large deflection of an elastically-bossed layered plate under pretension due to lateral load is studied. The approach follows von Karman plate theory for large deflection for a symmetrically layered isotropic case. The thus derived nonlinear governing equations are solved using a numerical finite difference method with the aid of an iteration scheme. For a nearly monolithic plate with a thin boss, the obtained solutions correlate well with those available in literature for a single-layered flat plate, thus validates the presented approach. For three layered symmetric plates made of typical silicon based materials, various initial tension and lateral pressure are implemented. The results indicate that, edge behavior may appear at both the boss edge and the clamped end of the plate, thereby revealing severe variations for the structural responses. Varying the central boss size and relative thickness may have a sensible influence upon the behavior of the bossed layered plate. Furthermore, lateral pressure appears to have a sensible effect upon the nonlinear behavior of the bossed layered plate. For a relatively large initial tension, however, the pretension effect dominates, yielding a total membrane behavior for the bossed plate, regardless of the size of the center boss, except in the vicinity of the clamped edge.
Analysis of the Impact of the New Emissions Limits on the Temperatures of the Vehicle Floor
Authors: Bicalho Gustavo Inácio , Baptista Bruno de Souza , Silva Felipe Vereza Lopes da , de Morais Hanriot Sérgio , Cabezas-Gómez Luben , Maia Cristiana Brasil
Published: February 2012

The Kyoto Protocol established the reduction of pollutant emissions limits for all sectors of industrial economy in 8%, compared to 1990´s levels, to be adopted in the period between 2008 and 2012. Individual countries defined a progressive scale for the emission reduction applied to automotive vehicles. These new emission limits are reached altering the calibration of the Electronic Central Unit (ECU), altering the volume and the composition of the catalytic converters and also adding new components to the engine, such as EGR (exhaust gas recirculation) system and phasing sensor. This work evaluates the impact of these modifications in the exhaust system temperatures and in the peripherical devices. In order to meet the requirements of the new emissions limits, the volume of the catalytic converter is higher, increasing the heat rejected. It provokes a temperature raise on the exhaust system and under the vehicle pavement, which impact the functionality of some components and also the passenger's thermal comfort. It is observed that the new emission standards in Brazil resulted in an increase of the vehicle temperatures, affecting the passengers’ thermal comfort, and eventually producing more emissions due to the use of an air conditioning system.
Effects of Process Parameters on Surface Quality in Turning of Mild Steel with Rotary Cutting Tool
Authors: Kiyak Murat , Altan Erhan
Published: February 2012

In machining processes, great amount of the cutting energy transforms to heat energy. Tool life decreases and the quality of the machined surface changes by the effects of heat during machining. Many researches are being done on the reduction of the negative effects of the heat on the tool. In this respect, cutting fluids are used, but usages of them are limited because of their some harmfully effects to the environment. In order to reduce the tool wear and to use the tool longer, during cutting continuously variation of the contact region of the tool and the chip can been realized by using self-propelled rotary tools. The tool life is longer in rotary tools when compared with stationary cutting tools. In machining with these tools lower heat effect at the cutting edge is observed. In this study, the effects of cutting parameters on surface roughness of machined part has been investigated during the turning of mild steel using self-propelled rotary tools. In experiments, cutting tools which inclination angles were 20°, 30° and 45° and rake angles were 0° and-5° were used. Cutting speeds were taken as 60 m/min and 120m/min. RCMX insert with 32mm diameter was used. Feed were chosen as 0.1, 0.2 and 0.4 mm/rev and cutting depth was set at 0.25 mm.
An Analytical Model for Chemical Etching in One Dimensional Space
Authors: Amirabadi Hossein , Rakhshkhorshid M.
Published: February 2012

In this paper an analytical model for chemical etching in one dimensional space has been presented. Regarding to the special specifications of Ferric chloride, etching of an Aluminum work piece exposed to Ferric chloride etchant has been modeled. The proposed model shows that, in the condition of constant reaction parameters, etching rate is a linear function of time. Excellent agreement between the proposed model and the experimental results, published by Çakır (2008), validates the model. By generalization the proposed model, etching rate, or in the other word depth of etch in a specified time, for different materials with different etchants can be predicted.
A New Control Method for Using Inkjet Printer Motherboard as 3 Axes CNC Router's Motion Control Card
Authors: Buyuksahin Utku
Published: February 2012

As the inkjet printers have two axes of movement, (one for scrolling of the paper and one for travelling of the cartridges) inkjets have closed loop stepper motor control cards for two axes which can be used in CNC routers. There are few studies in literature and internet about this method. The main difficulty while using these cards as motion control card is to send the motion data of the cutting process to the CNCs motor drivers. As programming ability is needed, this is the point where the projects are mostly left unfinished. In this study, a new method to help use of printer motherboards as CNC router motion control cards, with no need of programming skills and buying expensive software, is given. In this method, the third dimension of the picture is represented by colors. After drawing the two dimensional top view of the workpiece with any simple graphics painting software which can be found in every computer like Paint, is painted with the colors black to white, from the lowest level to highest respectively, like in the geographical maps which the oceans are painted darker to lighter according to the depth. As it is known that there are 16.7 millions of colors between black and white, the system is impressively precise in Z axis. The analogue signals of the colors which are sent from printers motherboard to the cartridges are captured with a PIC based circuit, which is designed for this project. Then the color codes are converted to Z axiss position data and PWM signals that are needed in Z axis motion. The X and Y axes stepper motor control PWM signals are generated by printer motherboard and used in the system just as is. While doing the cutting process on a printer motherboard attached CNC, the computer assumes as if a picture is being printed with the printer that is connected to USB or parallel port. This method is candidate to be one of the most common used home based or laboratory based CNC control methods in the near future.
Effect of Extrusion Ratio on Microstructure and Mechanical Properties of As-Cast AZ91D Magnesium Alloy
Authors: Zhang Bao Hong , Zhang Zhi Min
Published: February 2012

In order to study the effect of deformation extent on microstructure and mechanical properties of as-cast AZ91D magnesium alloy, experiments of direct extrusion were performed at temperature of 420 and different extrusion ratios. The microstructure and mechanical properties of billets and extrudates were measured. Experimental results show that the grain size of as-cast AZ91D magnesium alloy can be dramatically refined by extrusion. Direct extrusion can obviously improve the mechanical properties of as-cast AZ91D magnesium Alloy, comparing with the pre-extruded billet, the tensile strength, yield strength and elongation of extrudate can be improved by at least 83%, 154% and 150% respectively. As the extrusion ratio increases, the tensile strength and yield strength of extrudate will increase at first and then fall.
Cutting Forces in Dry Machining of Aluminum Alloy 5083 with Carbide Tools
Authors: Davoodi Behnam , Payganeh Gholam Hassan , Eslami Mohammad Reza
Published: February 2012

In the machining of Aluminum alloys used in lightweight structural application in automotive, shipbuilding and aerospace industries the consumption of cooling lubricant during the machining operations is very important. Among these, non-heat treatable aluminum alloy 5083 because of its reasonable strength, better corrosion resistance, weldability and ability to take surface finishes is better than the others. The associated costs of coolant acquisition, use, disposal and washing the machined components are significant, up to four times the cost of consumable tooling used in the cutting operations. To reduce the costs of production and to make the processes environmentally safe, the goal of the aeronautical manufacturers is to move toward dry cutting by eliminating or minimizing cutting fluids. This goal can be achieved by using coated carbide tools at high cutting speeds. To achieve this goal, different cutting conditions were tested in dry conditions. The elementary orthogonal cutting process was chosen, the cutting and feed cutting forces components were measured by using Kistler force dynamometer.
Short Time Perturbation Solution for Thermoelastic Instabilities in Planar Solidification
Authors: Yigit Faruk
Published: February 2012

A simplified thermomechanical growth instability model for early stages of solidification porcess is obtained. The model consists of a thermally deformable mold of finite thickness. The inclusion of the mold into the model introduces a parameter known as distortivity which plays an important role in the thermoelastic instability problems. The results show that the perturbation in contact pressure tends asymptotically to a maximum value at larger values of time. The magnitude of the contact pressure perturbation decreases as the thickness of the mold increases whereas it increases as the distortivity of the mold increases.
Effect of Mold Coating on Shell Morphology in Solidification
Authors: Turgut M. Nurullah , Demir M. Hakan , Yigit Faruk
Published: February 2012

The mold-shell interface plays a very important role during the earliest stages of metal casting processes. Heat is extracted from the molten metal through this interface resulting in the growth of the shell. Small spatial variations in heat extraction can lead to shell morphological instability where certain regions of the solidification front grow preferentially over others. This may cause cracks in the shell which can greatly reduce the integrity of the final cast product. Mold coating at the mold-shell interface is one of the most important factors controlling the heat transfer and, hence, it has very important role on the solidification rate and development of microstructure. In this paper, a linear perturbation method is used to solve a two-dimensional heat conduction problem in which a liquid, becomes solidified by heat transfer to a planar mold of finite thickness. The influence of physical parameters such as the coating material thickness, conductivity and thermal contact resistance on the growth of solidified shell thickness is investigated. The present work can form the thermal part of a subsequent investigation of related thermo elastic stress problems.
Casting Quality of Gypsum Bonded Block Investment Casting Moulds
Authors: Guler Kerem Altug , Cigdem Mustafa
Published: February 2012

In this study surface finish and dimensional charactersitics of castings produced with gypsum bonded block investment moulds were investigated. Commercial and laboratory made gypsum bonded investment moulds were used for investment casting mould making. To compare the casting quality of the investment powders, wax patterns for surface roughness specimens and linear dimension measurement specimens were designed and produced with special geometry. Wax trees were assembled with these patterns, cylindrical stainless steel perforated flasks were settled around the trees and gypsum bonded investment slurries were filled into flasks. Conventional tin bronze was subsequently cast into these moulds by vacuum assisted casting process. Afterwards, surface roughnesses of specimens were measured and linear dimensions of wax patterns and cast specimens were compared to determine percantage of dimensional change.
Metal Injection Moulding of ZK60 Magnesium Alloy Powder Using Palm Stearin Based Binder System
Authors: Harun Mohd Ruzi , Muhamad N. , Sulong Abu Bakar , Mohamad Noraiham , Jamaludin K.R.
Published: February 2012

This paper presents a new fabrication process for producing magnesium alloy components via metal injection moulding (MIM). Here, four kind of feedstock with 62, 64, 66 and 68% powder loading were prepared by a mixture of gas atomized ZK60 magnesium alloy powder with a resin consisting of palm stearin and low density polyethylene. The rheological investigation of the feedstock was carried out and the optimal powder loading was determined. The optimal powder loading feedstock was then injected by screw type injection moulding machine. The effects of injection moulding parameters on the physical and mechanical properties of green compacts were evaluated. The results showed that injection moulding of a feedstock containing 64% magnesium alloy was possible at high barrel temperature and pressure.
Laser Cutting of Ceramic and Thermal Efficiency Analysis
Authors: Sahin Ahmet Z. , Yilbas Bekir Sami , Ayar T.
Published: February 2012

Laser cutting of ceramics offers considerable advantages over the conventional cutting methods. Some of these advantages include precision of operation, high speed processing and low cost. In addition, cutting process is independent of the mechanical properties of the ceramic material such as hardness and fracture toughness. Alumina is one of the widely used ceramics in industry due to their resistance to harsh environments. Laser cutting of alumina requires high laser power due to high latent heat of melting and elevated melting temperature. In efficient laser cutting process, the low laser power is required. Consequently, for optimum laser cutting conditions of alumina tiles, the thermal efficiency of the cutting process may not be a maximum. The optimum laser cutting parameters provide crack free and parallel edge cuts. Therefore, investigation into laser cutting of alumina ties and the efficiency analysis becomes essential. In the present study, laser cutting of alumina tiles with 3 mm thickness is carried out and thermodynamic analysis associated with the efficiency analysis is introduced. The lump parameter method is incorporated in the thermodynamic analysis. The optimum cutting conditions are then related to the first and second law efficiencies.
The Effects of Position of the Laser Beam on the Pulsed Nd: YAG Laser Weld Microstructure of AISI 630 and AISI 321 Stainless Steels
Authors: Akbari Mousavi Seyed Ali Asghar , Sufizadeh A.R.
Published: February 2012

The study was conducted to investigate the effects of laser beam position on the weld microstructure of AISI 630 and AISI 321 stainless steels. The optical and scanning electron microscopy and x-ray diffraction of the weld microstructures were carried out. The results showed that if the laser beam was focused at the interface, austenite, marensite and ferrite microstructures were formed at the weld region. If the laser beam was focused toward the AISI 630 stainless steel denoted as sample P in the manuscript, the martensitic-ferritic microstructures were produced in the weld cross section. If the laser beam was focused toward the AISI 321 stainless steel designated as sample A in the text, the austenitic microstructure was produced in the weld bead. The maximum hardness in all samples was occurred at the AISI 630 interface.
Factors Influencing on the Dimensions Accuracy in Laser Cutting
Authors: Dikova Tsanka D.
Published: February 2012

This research aims to establish the influence of different factors on the dimensions accuracy in laser cutting. Samples with different thickness were made of DC01 EN 10130 steel. On each sample 32 round or square holes were cut in 4 rows by different laser beam movement schemes linear, zig-zag and random. The tests were made by pulse CO2 laser with regimes, recommended for each sheet thickness, by the machine operating manual. The diameters of the round holes and the dimensions of the square holes along the laser head and the table axes were measured by a projector. The varying intervals of the dimensions and the shape deviations were calculated. It was established that three groups of factors influence on the dimensions accuracy in laser cutting: factors, related to the machine, laser parameters power, laser cutting speed and focus distance, determining the technological process parameters, and the material characteristics thermal physical properties and sample sizes. Factors, related to the machine, exert effect mainly on the intervals of dimensions varying, while the laser parameters and the material properties influence on the dimensions value independently of the cutting scheme. In the all laser cutting schemes the increasing of the sample thickness leads to the larger interval of the dimensions varying and increasing of the shape deviation. Nomenclature
Laser Processing of Quartz for Microfluidic Device Fabrication
Authors: Azouz A. Ben , Vázquez M. , Paull Brett , Brabazon Dermot
Published: February 2012

This paper presents a fast fabrication process of microfluidic channels with quartz substrates. Microchannels were ablated on the surface of quartz samples with a CO2 laser. Double sided Pressure Sensitive Adhesive (PSA) was applied to bond the samples with scribed microchannels to flat glass sheets. Dimensions of the fabricated channels were characterised with optical microscopy and laser profilometry. The recorded data was modelled with a BoxBehnken experiment design using Response Surface Methodology. Characterisation included also the measurement of optical transmission through the processed glass and measurement of flow rate through the fabricated channels. With an average width of 165 µm and depth of 280µm, fabricated channels had appropriate dimensions for a range of microfluidic applications. A significant width of the laser processed channels provided 100% transmission for a wide range of the optical spectrum. These fabricated channels were also shown to not significantly retard the fluid flow rate thus making these channels applicable for integration into numerous detection systems for chemical separation applications.
Effect of Mould Vibration on Mechanical Properties of Particulate Reinforced Aluminium Alloy Matrix Composite
Authors: Sayuti Muhammad , Sulaiman Shamsuddin , Baharudin B.T. Hang Tuah , Arifin M.K.A.M. , Vijayaram Thoguluva Raghavan , Suraya S.
Published: February 2012

This paper focuses on the mechanical properties of Titanium Carbide (TiC) particulate reinforced aluminium-silicon alloy matrix composite subjected to mould vibration during solidification. In this experimental study, mould vibration is applied to TiC particulate reinforced LM6 alloy matrix composites with a wide range of frequencies. TiC particulate reinforced LM6 alloy matrix composites are fabricated by adding different particulate weight fraction of TiC in the matrix by carbon dioxide molding process. Mechanical properties such as tensile strength, hardness, are determined and microstructural features are analyzed through SEM. Besides, fracture surface analysis has been performed to characterize the morphological aspects of the test samples after tensile testing. Preliminary works show that the mechanical properties have been improved with 10.2Hz frequency when compared with the gravity sand-castings without vibration.
Modeling of Functionally Graded Thermopiezoelectro-Magnetic Materials
Authors: Sunar M.
Published: February 2012

Previous work has shown the importance of the mechanical behaviour of coatings and thin materals, where the elastic properties vary in depth. Such coatings and materials are investigated under the broad subject of Functionally Graded Materials (FGMs). There has been also a vast interest in the general coupled field analysis of thermopiezomagnetic materials under which smart piezoelectric and magnetostrictive materials can be studied. The smart materials are often bonded as thin films on host structures for the purpose of sensing and/or actuation. This work aims to combine these two important areas of thermopiezoelectro-magnetism and FGMs. The thermopiezoelectro-magnetic materials are modeled using the finite element method assuming variations in material properties similar to FGMs. The resulting equations of modeling are then applied to an example problem in smart material sensing/actuation.
Preperation of Lead-Free Potassium Sodium Niobate Based Piezoelectrics and their Electromechanical Characteristics
Authors: Berksoy Ayse , Mensur Alkoy Ebru
Published: February 2012

In this study, %7 Li modified and 0.67 % copper oxide added potassium sodium niobate (KNN) ceramics were investigated. Copper oxide was used as a sintering aid. The ceramics were prepared with conventional solid state calcination technique. All samples were crystallized in pure perovskite phase with no additional peak. The density of the samples increased with copper addition and lithium modification. The Curie temperature of KNN ceramics was found to shift to lower temperatures by CuO addition. The Curie temperature was measured as 414°C and 504°C for copper oxide added and lithium modified KNN samples, respectively. The maximum strain of copper oxide added sample was 0.12%, whereas Li modified KL ceramics yielded up to 0.10 %.
Investigation of Mechanical Performance of Squeezed Magnetorheological Fluid Using Response Surface Method
Authors: Ismail Izwan , Mazlan Saiful Amri , Zamzuri Hairi , Olabi Abdul Ghani
Published: February 2012

In this paper, effects of critical parameters, namely initial gap, squeezing speed and applied current were statistically investigated on the mechanical behaviour of MR fluid in squeeze mode. A set of 17 experiments was designed using Design Expert 7 software to gather data from response surface methodology (RSM). The responses in terms of compression modulus were then calculated. An MRF132-DG was used as a sample in each experiment. The experiments were conducted under compression stress mode using universal testing machine (UTM). Stress-strain curves were analysed using the machine integrated TestXpert analyser software package. The stress-strain curves of MR fluid under squeeze have produced a shear thickening behaviour at 13.54 MPa of the highest stress at 0.75 of strain. A correlation between the three parameters and the stress-strain properties was specified. The results showed that the initial gap and supplied current were significantly produced a high compression modulus for the MR materials. These findings are important to enhance the capability of the squeeze MR devices to operate at its best performance. High compressive stress is crucial for most magnetorheological (MR) materials, particularly in squeeze mode devices.
Bending Fatigue Behaviour of Laminated Sandwich Beams
Authors: Coskun Onur , Türkmen Halit S.
Published: February 2012

In this study, the bending fatigue behaviour of laminated sandwich beams, which are made of carbon/epoxy face sheets and aramid honeycomb core, has been investigated experimentally. The wet hand lay-up technique is used and curing is processed on the heated vacuum table at an elevated temperature to manufacture the sandwich beams. The experimental set-up for bending fatigue test provides a cantilever in one end and a cyclic load at the free end with constant displacement amplitude at room temperature. The load applied to the beam is measured using a load cell during the bending test. Different displacement amplitudes are performed. Mechanical properties, bending stiffness and free vibration frequency of the sandwich beam are investigated. The bending test of the beams and vibration identification test using a vibration analyzer, a hammer and an accelerometer are performed to measure the bending stiffness and determination of free vibration frequency of the clamped sandwich beams before starting and after completion of the fatigue tests. The bending stiffness and free vibration frequencies before and after the fatigue tests are compared to understand the effect of repeated loadings on the mechanical performance of the laminated sandwich beams.
Material Selection and Process Design Optimization Framework under Closed-Loop Supply Chain
Authors: Ndiaye Malick M.
Published: February 2012

With an industrial era characterized by new regulations aiming at protecting costumers and the global environment, manufacturers have to be more effective in delivering products that meet customers requirement but also, they have to be apt to dispose of the products properly whenever customers decide to return them. The traditional role of material selection and process design are challenged to take these issues into consideration and provide more effective solutions for the entire (closed-loop) supply chain. We aim at studying the impact of material and process selection decisions in the design of the reverse supply chain. We present an integrated approach that consolidates these design frameworks, and also a total cost approach to be used to set products end of life management decisions.
Microstructure Characterization of Low Carbon Steel Used for Galvanization
Authors: Larouk Z. , Yakhlef F.
Published: February 2012

The present study deals with a low carbon steel containing 0.09%C (weight %). This steel is produced by Trifisoud El-elma-Setif Algeria as wires and used for galvanization. Tensile tests are carried out on the material in as received conditions, i.e before, after deformation and after galvanization. Optical microscope and Secondary Electron Microscope (SEM) are used for microstructure characterization of the material. The results show that the initial microstructure is ferrite-pearlite with 11µm of ferrite grain size. SEM observations show that the galvanization layer is not regular and it thickness varies between 5 and 13µm. It has been found that the mechanical properties are affected by the rate of deformation. The annealing treatment at 530°C for different time follows the Avrami law. The two constants in Avrami law (n, k) are determined. The obtained results are compared with other published works.
Grain Refinement in Medium Chromium Ferritic Stainless Steel Welds via Aluminum Powder Addition
Authors: Amuda M.O.H. , Mridha S.
Published: February 2012

Grain refinement in medium chromium ferritic stainless steel weld was attempted via elemental (aluminum) powder pre-placement technique prior to melting under a TIG torch. A Box-Behnken experimental design was adopted with current, travel speed and the amount of aluminum powder added as the process factors for producing weld pool. The resolidified weld tracks were characterized using microscopy, microhardness and mechanical testing. The degree of grain refinement achieved was evaluated using a scaling index known as Grain Refinement Index (GRI). The findings showed that the GRI is influenced by the concentration of the aluminum powder introduced into the melt pool. Furthermore, high GRI does not necessarily translate to better mechanical properties relative to the conventional weld. This suggests that the grain size effect might not be the only factor influencing the property of weld metal. However, weld track treated with 0.08mg/mm2 of aluminum powder exhibited about 20% improvement in properties relative to the conventional weld made under the same energy conditions.
Weldability of New Ferritic Stainless Steel for Exhaust Manifold Application
Authors: Villaret Vincent , Deschaux-Beaume Frederic , Fortain Jean Marie , Fras Gilles , Januard Fabien
Published: February 2012

In the current context of fossil energy scarcity, car manufacturers have to optimize vehicles energy efficiency. This and continuous improvement includes a change of the exhaust manifold design. Usually in cast iron, exhaust manifolds tend to be mechanically welded in order to fit new constraints such as lightness, durability, efficiency and small size. To achieve such requirements, ferritic stainless steels with high chromium content (19%) and molybdenum (2%) are developed. For the welding, the use of existing filler wire does not satisfy fully the application requirements. This leads to oxidation problems and / or thermal fatigue strength that drastically reduces assembly lifetime. New flux cored wires are developed in the context of this study in order to provide molten zone characteristics close to those of the base metal. Different chemical compositions are tested in order to highlight the influence of stabilizing element on microstructure. Welding tests revealed the major influence of titanium on the grain refinement in the molten zone. A minimum Ti content of 0.45 weight % in the filler wire is required to be efficient as grain refiner.
Onset of Progressive Buckling by Inertia Force in Axial Impact of Straight and S-Curved Square Tubes
Authors: Yamashita Minoru , Hattori Toshio
Published: February 2012

For the improvement of the deformation characteristic and the energy absorption efficiency of the tubular structure at impact event, a method generating the first buckling lobe using the inertia force was investigated. The solid block was attached to the wall so that its inertia force causes the partial plastic deformation that plays a role of the trigger of progressive buckling at the beginning of impact. Drop-weight impact experiment revealed that the onset of progressive buckling was achieved at the desired portion by the method. To increase the variety of tube shapes, numerical examination was conducted with the dynamic explicit finite element method. Long straight and S-curved tubes, which have square cross-section, were numerically modeled with shell elements. They were assumed to be impacted to the rigid wall to estimate the dynamic collapse behavior. The first buckling lobe generated by inertia force was demonstrated for the straight tube. The S-curved tube exhibited a bending collapse mode without the method. However, such mode was avoidable by applying the method. Then the energy absorption efficiency of the tube was drastically increased.
Performance of Micro-Hole Drilling by Ultrasonic-Assisted Electro-Chemical Discharge Machining
Authors: Rusli Meifal , Furutani Katsushi
Published: February 2012

Electro-chemical discharge machining (ECDM) is one of nontraditional processes for micro-fabrication of non-conductive materials. A high applied voltage is preferable to form a gas film and to generate discharge in the film. However, accumulation of discharge heat often causes cracks of the surface because non-conductive materials have low heat conductivity. In this study, the effect of ultrasonic vibration and the electrolyte level on the performance of gravity-feed drilling by ECDM was investigated. Ultrasonic vibration was applied to a glass plate. A tungsten rod as a tool electrode was fed by gravity. Ultrasonic vibration changed the discharge behavior and improved electrolyte circulation. Although high amplitude ultrasonic vibration caused very dense and wide current pulses consistently during machining process, it decreased removal rate significantly. In addition, electrolyte levels affect single bubble size and the resistance in the electrolyte. Low electrolyte level will cause higher resistance, and higher temperature of the tool electrode and workpiece. A high bias current flew at a low electrolyte level without ultrasonic vibration. In this case, removal rate decreased and surface integrity was improved.
Mechanistic Model of Work-Piece Diametrical Error in Conventional and Ultrasonic Assisted Turning
Authors: Soleimanimehr H. , Nategh Mohammad Javad , Jamshidi H.
Published: February 2012

The spring back is a major source of diametrical error occurring in turning of workpieces. In order to analyze diametrical error, an elastic deflection model of workpiece should be available. Many assumptions are usually taken into consideration when analyzing the elastic deformation of workpiece. Many studies have been done to find the analytical model of work-piece spring back and its suitable cutting force model. When compared with experimental data, developed models in these works are associated with considerable errors. In this paper, through using experimental results, an efficient elastic deformation model of workpiece has been obtained which can be compared with analytical model. Many experiments were performed, and some different functions were produced which predict the trend of experimental results. Finally, an appropriate model with the lowest error was suggested. The same process has been performed in ultrasonic vibrations assisted turning. The obtained functions will be suitable to compensate for the diametrical error occurring by machining forces. Finally this model has been used to obtain the amount of elastic spring back of tool and spindle.
Influence of the Recycled Material Percentage on the Mechanical Behaviour of HDPE for Injection Moulding Process for an Ecologycal Design
Authors: Javierre Carlos , Fernandez Angel , Camanes Victor
Published: February 2012

Nowadays plastic materials recycling aims most of the time to use the recycled material to manufacture products of less requirements than the original products, so the material is depreciated. It would be important to recycle plastic materials to use them for the same applications they were initially used. To make this possible it would be necessary to characterize the recycled material properties, design products taking into account that they are going to be produced with recycled material and to be able to recuperate the product at the end of its lifetime. An example of this designing philosophy is going to be presented in this work, applied to large trash containers produced with HDPE (RIGIDEX5740UA), where the product can be easily recovered at the end of its lifetime and also the amount of polymer material wasted during thermoplastic injection moulding is very high. Recycling mills convert parts into small pieces that are used as feed material for injection again, by mixing it in different percentages with raw material. This mixture of both raw and recycled material modifies material properties according to the percentage of recycled material introduced. Some of the properties affected by this modification are those related to mechanical behaviour. This paper analyzes the mechanical behaviour of material with different percentages of recycled material. Test parts have been injected with different percentage of recycled material and have been tested by a tensile machine. Results like; Stress at yield, Stress at break and Young Modulus have been calculated and analysed. The product of this work has been designed using only one plastic material, which is very helpful from the point of view of manufacturing and recycling. In these kinds of parts a very tight safety factor is used, thats why to know exactly material properties is very important during its design.
Resource Allocation and Job Dispatching for Unreliable Flexible Flow Shop Manufacturing System
Authors: Al-Turki Umar M. , Saleh Haitham , Deyab Tamer , Almoghathawi Yasser
Published: February 2012

Resource allocation, product batching and production scheduling are three different problems in manufacturing systems of different structures such as flexible flow shop manufacturing systems. These problems are usually dealt with independently for a certain objective function related to production efficiency and effectiveness. Handling all of them in an integrated manner is a challenge facing many manufacturing systems in practice and that challenge increases for highly complicated and stochastic systems. Random arrival of products, machine setup time requirements, unexpected machine breakdowns, and multiple conflicting objective functions are some of the common complications in such systems. This research attempts to study the integrated problem under the mentioned complications with various objective functions. The decisions parameters are the batch size, the number of machines at each workstation, and the dispatching policy. Discrete event simulation is used as an optimization tools. The system is modeled using the ARENA software and different scenarios are tested for optimum parameter selection under different conditions.
A Virtual Prototyping System for Additive Manufacturing Process Development
Authors: Topcu Okan , Tascioglu Yigit
Published: February 2012

This paper describes a virtual prototyping (VP) system which is a part of an open source software package for an additive manufacturing (AM) process under development. The VP system facilitates the product development by uniting the AM process and virtual reality in order to produce digital prototypes. Moreover, it combines particle based and layer based processes by including powder-like particles as its basic material. These particles are used as color codes in the VP system. This coding enables obtaining basic building blocks in homogeneous state or in heterogeneous state by mixing with other particles. These blocks or bricks are collated side by side to obtain the heterogeneous material property all over the solid body. The thin layers obtained by these bricks are then subsequently stacked up to fabricate a virtual prototype. Construction of multiple material prototypes is possible due to selective-additive nature of this process. The effectiveness of the proposed system is demonstrated by processing a model of The Maidens Tower.
Correlation of Input Parameters with Tool Martial on the Output Parameters of Electrical Discharge Machining Process
Authors: Shabgard Mohammad Reza , Seyedzavvar Mirsadegh
Published: February 2012

This paper details the correlation between the input parameters with the tool material on the machining response in comparison of two different combinations of toolworkpiece material, namely copper-H13 and graphite-H13. The considered machining input parameters included pulse current and pulse on-time, and the investigated characteristics of the machining response were the material removal rate, tool wear, and surface roughness of the workpiece. Furthermore, differences in pulse shapes and process stability between the copper-H13 and graphite-H13 combinations were investigated.
Developing an Executive Information Site Monitoring System
Authors: Zakaria Wan Zahran , Abd. Majid Muhd Zaimi , Nourbakhsh Mehdi
Published: February 2012

Progress monitoring and control is one of the most important tasks of management project. Basically, construction works produce a lot of information that were required by top managements of construction organizations to track the work progress on site. A recent issue highlighted by top managements is inefficiency in obtaining information from project site on time. Hence, the focus of this research is to establish a computerized information system that can be utilized by top management in order to evaluate the construction progress. The aim of this research is to develop a computerized project progress monitoring entitled Executive Information Site Monitoring System (EISMS). In order to develop EISMS, Classic Waterfall Model has been considered as a basis for system development. The development process started by identifying system requirements, followed by EISMS proposal, EISMS design, EISMS implementation, and ended up with system validation and verification. In conclusion, EISMS was successfully developed and implemented during construction phase which allows top management of construction organization to monitor the construction site progress more efficiently and helps them in the decision making and taking timely appropriate action.
Experimental Study and Theoretical Analysis on Seismic Performance of RC Shear Wall with STRC Columns and Embedded Steel Plate
Authors: Cao Wan Lin , Dong Hong Ying , Zhang Jian Wei
Published: February 2012

RC shear wall with STRC (steel tube-reinforced concrete) columns and embedded steel plate has been proposed and used in the project of an International Conference Center. In order to ascertain the seismic performance of this kind of composite shear walls with different openings in the practical engineering, four 1/7 scale specimens with shear span ration 2.0 were tested under low-frequency cyclic loading. The load-carrying capacity, ductility, stiffness and its attenuation, hysteretic property, energy dissipation capacity and failure mode of the specimens were analyzed. The effect of the embedded steel plate and the concealed steel trusses on the seismic performance of the walls was studied. The results show that the ductility and load-carrying capacity of RC shear wall are improved greatly by setting the embedded steel plate or concealed steel trusses in the wall; The embedded steel plate and the concrete work very well through the stud connectors welded on the steel plate and the tie bars inserted in the walls; The STRC columns have the advantage of higher load-carrying capacity, not easy to crack and better ductility; The new composite shear wall has good seismic performance and important practical value. It is suitable for large and complex application of high-rise buildings in the seismic regions.
Analytical Study of Seismic Progressive Collapse in a Steel Moment Frame Building
Authors: Parsaeifard Niloofar , Nateghi Alahi Fariborz
Published: February 2012

Progressive collapse is defined as total or remarkable partial collapse of structure following the damage occurred at a small portion of the structure. In most cases, the study is focused on progressive collapse of structures due to explosion, vehicle impact, fire and other man-made hazards; with less attention on progressive collapse mechanism of structure due to earthquake. Although the post earthquake inspections show that structural elements, mostly columns in the corner of the plan, can be severely damaged during earthquake. If neighboring columns are not properly designed to resist and redistribute the additional gravity load that is imposed by the column loss, partial collapse of the structure will occur; which would lead to progressive collapse of the structure. In this regard, progressive collapse potential of a moment resisting steel building is investigated via analytical procedure under earthquake action. In this research, a corner-column of the building was weakened intentionally to navigate the damage toward a certain part of the structure. Then, nonlinear static analysis is carried out on the three dimensional model of the building and the total behavior of the structure is studied. The results indicate that after the failure of the corner-column, the lateral resistance of the frame in which the removed (failed) column was located decreases, and the failure of the other columns occurs. Large plastic deformations and the failure of the other members could cause progressive collapse in the whole structure and the expected ductile behavior of the structure would not be observed.
A Simplified Model and Experimental Response of Self-Centring Bridge Piers with Ductile Connections
Authors: Guo Jia , Xin Ke Gui , Wu Wei Ping , He Ming Hua
Published: February 2012

A self-centring bridge pier is a combination of elastic recovery devices and internal or external energy dissipaters. During the cyclic loading test, it is proved that the self-centring system can minimize the residual drift of the pier whereas holding sufficient energy dissipate capacity as well as bearing capacity. It is worth noting that a simplified analytical model is proposed based on the experimental response regarding flexural deformation, unbounded length of mild steels and strain penetration. Comparison between the analytical model and test results has indicated that a reasonable envelope of the cyclic behavior of the system can be achieved by the model presented.