bluuebunny/crossref_metadata_2025 huggingface dataset:
Design and Analyses of a Propeller for Underwater Vehicles Using Computational Fluid Dynamics
Authors: Gungor Emre , Ozdemir Ilyas Bedii
Published: October 2015

This paper presents results of computation of a unique propeller design for underwater vehicles using an original in-house algorithm which is developed for the problems of fluid dynamics. Specific software based on finite volume calculations are used to validate design procedure. Conventional propellers having experimental results are good choice to investigate the convenience of solutions. Cavitation tunnel test results of two types of conventional propeller namely P-4382 and P-4119 were considered as a test-case study. The characteristic performances of those were all compared with CFD analysis for different conditions to realize the effects of mesh generation, discretization method and turbulence model in numerical process. Design criteria for unique propeller were selected according to underwater vehicle performance and its requirements. Then the method performed in validation stage was entirely implemented to the new design to observe its performance curves. The results show that this new propeller design is capable of providing desired thrust, vehicle velocity and power output with high efficiency for underwater vehicle. Algorithm implementation, mesh generation, turbulence models and solution methods in CFD process are so suitable that results of analyses are matching with experiments.
Computational Fluid Dynamics Simulation of Steel Bars Cooling by Free Convection and Thermal Radiation
Authors: Terenzi Seixas Paulo Henrique , Silva Paul Campos Santana , Huebner Rudolf
Published: October 2015

In this article, the pilling process of hot steel bars is analyzed. During the loading three bars are placed over a wood surface, after those other three are placed over the previous for two times with 5 minutes intervals between them.They are all subject to a slow cooling by thermal radiation and free convection.A Computational Fluid Dynamics (CFD) model to predict the temperature profile of them is developed. Comparison between the CFD simulation results and experimental data yielded an average difference in the bars temperature between -0.3oC and 3.5oC.
Evaluation of Spray Drying Behavior by Model Simulation
Authors: Chaves Diego Henrique de Souza , Birchal Marco Aurélio de Souza , Birchal Viviane Santos
Published: October 2015

This works presents a steady state behavior modeling and simulation study of spray dryer operational parameters and their influence on final product. Experimental data of skim milk drying was used to validate the simulator. However, the model is general and can be used for other materials of known properties. Changing sorption isotherm equation and adjusting specific heat capacity of solids, required quality specifications can be estimated by the simulator to any product, which can also determine the best operational parameters of the dryer.
A Practical Solution for Reducing Critical Height in Drain Sink Problem during Ladle Teeming Process
Authors: Schor Roberto , Monken Vítor P. , Coelho Raniro , Oliveira Leandro S.
Published: October 2015

A common problem that affects the continuous casting process is the formation of a sink funnel or a vortex funnel in the end of the teeming process of a steel ladle. This causes the slag to be carried over with the molten steel to the tundish, generating inclusions in the produced steel ingot. In this work we propose an innovative device designed to delay the sink-funnel formation and hence decrease the critical draining height. The apparatus consists of an air-suctioning spear that induces a reduced pressure gradient just above the slag/air interface, in a position vertically alignedwith the draining nozzle axis. The device operation was modeled with Computational Fluid Dynamics (CFD). The results showed that the introduction of the suctioningspear allowedfor an optimizedladle teeming process, resulting in a shorter critical draining height, thus, reducing the amount of leftover steel to be recycled.
Numerical Simulation of Solid Propellant Rocket Exhaust Plume Considering Two-Phase Flow Effects
Authors: Ma Yan Jie , Bao Fu Ting , Xu Hao , Sun Lin
Published: October 2015

Two-phase flow can have significance influence on exhaust plume of solid propellant, as well as the infrared radiation of the rocket. To show this influence, flow field of solid propellant rocket exhaust plume is simulated on different working conditions, where two-phase flow is involved using the DPM method. Comparing the flow filed results with or without two-phase flow considered shows that the existence of the condensed particles can decreases the velocity of the plume and increases the temperature. The influences of the flight height and Mach number on exhaust plume are also discussed.
Optimal Design of Wind Boosters for Low Speed Vertical Axis Wind Turbines
Authors: Korprasertsak Natapol , Leephakpreeda Thananchai
Published: October 2015

Although Vertical Axis Wind Turbines (VAWTs) are designed for performing mechanical works acceptably at medium wind speed, Standalone VAWTs are still unable to generate mechanical power satisfactorily for best practice at low speed wind. This study presents optimal design of wind booster, by utilizing Computational Fluid Dynamics (CFD). A wind booster is proposed to be implemented with a VAWT in order to not only harvest energy with low availability at low wind speed but also enhance performance of a VAWT at higher wind speed. In CFD-based experiments, guiding and throttling effects of the wind booster are able to increase mechanical power of a VAWT. Optimal alternatives of number and leading angle of guide vanes are determined by maximizing the coefficient of power from the alternating direction method as an optimization technique. The VAWT coupled with the optimal wind booster, which consists of 8 guide vanes and leading angle of 55o, is cable of producing mechanical power higher up to the coefficient of power of 4.8 % than the original design.
Numerical Validation of the Ethanol Spray Produced by a Direct Injection Injector for Different Pressure Conditions
Authors: Amorim Felipe Grossi L. , Guzzo Marcio E. , Reis Leonardo Mayer , Coelho R.O. , Valle Ramon Molina
Published: October 2015

This study presents a methodology to validate CFD simulations of the spray fuel injection using an experimental bench and optical measurement tools along with the Shadowgraph Technique. The parameter used for validating the experiments is the penetration rate, under situations of 6 bar and 100 bar injection pressures. The results show a penetration rate difference lower than 3% between the numerical model and the physical test. The visual plots, considering the shape and angles of the spray, also matched. Once validated, the numerical model could be applied to dynamic models of internal combustion engines and used to elaborate injection strategies for future projects.
Numerical Analysis of an Internal Combustion Engine Using One-Dimensional Code
Authors: Radicchi F.C. , Vieira J.M.G. , Fonseca Leonardo , Valle Ramon Molina , Barros José Eduardo Mautone
Published: October 2015

The work aims to model a spark ignition reciprocating Internal Combustion Engine - ICE. A code was built in Object Pascal to simulate another ICE and now it is being adapted to this research single-cylinder engine using commercial ethanol. The model describes in-cylinder gas by conservation equations, including the momentum conservation, and solves combustion wave equations, such that detonation and deflagration are calculated by the same set of formulas. Adjustments were made to get a proper discharge coefficient for the valves and represent the internal geometry. The mass flow rate calculated by the program differed in only 1% of the experimental value. The maximum pressures from combustion graphs differed in less than 1% too and their curves were similar. Other parameters of interest, also found to be close to the experimental ones, are presented and discussed. The code also showed as a good result the simulation time, which was approximately two minutes.
Macroscopic Analysis of Spray Development Using Direct Injection for Studying Ethanol Fuel Behavior
Authors: Guzzo Marcio E. , Gomes Carlos A.J. , Costa Roberto B.R. , Valle Ramon Molina , Barros José E.M.
Published: October 2015

A great difficulty in spray analysis is the intrinsic subjectivity in the manual measurements of macroscopic spray characteristics. Within its contexts this work has the main objective to demonstrate a systematic methodology for the spray analysis adopted for acquiring the data results based on numerical criterion dealing with the numerical matrices that represent the spray images. The results shown in this work refers to EXXSOL D60 injection, a tested fluid used to simulate ethanol spray characteristics. The characteristics analyzed were spray penetration, spray pattern at various moments after start of injection and the total volume of the cone spray also as a function of time. The methodology applied uses the numerical matrices of images in different stages of injections. A computational routine written in Matlab environment deals with the numerical matrices of the spray images to localize the spray boundaries based on a numerical criterion. All the subsequent analysis is then performed with the boundaries location data in hand. The results show higher growth of penetration in the beginning of injections, higher displacements of the bottom part of the spray also in the beginning of injections and a linear growth of spray volume injected. The importance of all the results acquired in this work demonstrated that the proposed methodology is suitable for spray analysis.
Adaptive Fuzzy Autopilot for a Scale Ship Model
Authors: Ramos Alcides , Contreras Juan
Published: October 2015

This paper discusses the implementation of an adaptive fuzzy autopilot for a scale ship model using a Fuzzy Model Reference Learning Controller (FMRLC). Initially, a fuzzy singleton model of the scale ship model is obtained from experimental input and output data gathered from the turning circle manoeuvre. After that, the paper describes how to design a Fuzzy Model Reference Learning Controller (FMRLC) for controlling the directional heading of the scale ship model. At the end, results of the implementation of the adaptive ship autopilot are showed.
Tool Condition Monitoring Using the Electromotive Force from the Chip-Tool Thermocouple
Authors: Roberto Ingraci Neto Rubens , Luis Fragelli Renan , Alves Fiocchi Arthur , de Angelo Sanchez Luiz Eduardo
Published: October 2015

Tool condition monitoring systems are extensively study. However, the machining processes are non-stationary and comprise many details that interfere in its monitoring. Aiming to develop a simple, low cost and efficient tool condition monitoring system, this study analyzed the electromotive force (EMF) from a chip-tool thermocouple in turning tests with AISI 1045. Since EMF comprises time and frequency variations related to machining conditions a Wavelet Packet Transform extracted the signals features from EMF. These signals features fed inputs of a neural network that aimed to evaluate the cutting tool maximum flank wear. The maximum error of the neural network was 1.88% for tested signals. Moreover, EMF showed changes that allow the detection of cutting tool breakage. Therefore, the chip-tool thermocouple may be a promising method for tool condition monitoring. This is the first report of electromotive force analysis in time-frequency domain aiming to quantify the wear of the cutting tool and evaluate its condition.
Elimination of the Collision States of the Effectors of Industrial Robots by Application of Neural Networks
Authors: Prada Erik , Baločková Lenka , Valášek Michael
Published: October 2015

The article deals with the usage of methods of learning algorithms of neural networks for solving of collision states problem within multi-robotic cooperation. Nowadays, multi-robotic cooperation is a highly used method of work of two or more industrial robots. The requirements for elimination of collision states are getting more difficult when the multi-robotic system is more complicated. Methods of neural networks provide suitable tools for solving of complex cooperating problems. In the beginning of the article, we discuss the term “collision state” and the possibilities of its solving. In the following chapter, we discuss the theory of neural networks and learning algorithms, which we applied in solving of the collision states. In the final chapter, we implemented the practical verification of the model neural network in JSNN programme. It consisted of creating and learning of the training data and subsequent verification of the test data.
Calibration of Positional Errors in Coordinate Measuring Machines and Machine Tools Using a Laser Interferometer System
Authors: di Giacomo Benedito , de Morais César Augusto Galvão
Published: October 2015

Dimensional inspections in manufactured workpieces allow assess the quality of the manufacturing process, in this context the quality and development of measurement systems are issues addressed by many researchers. The coordinate measuring machines (CMMs) are versatile systems, can measure complex geometries quickly and accurately. Positional errors are parts of volumetric error and affect the correct positioning of probe in CMMs or of the tool in machine tools. Faced with this, the purpose this investigation is show a method to calibrate the positional errors in a bridge-type coordinate measuring machine, this method collects data in dynamic mode and reduces cyclic errors. The calibration of positional errors was performed using laser interferometry in the “on-the-fly” mode and a method to reduce cyclic errors was applied. The highest value of position error occurred in x axis with value positive of 10μm in the position of 220mm, while in the y and z axis the higher absolute values were 2μm and 6μm respectively. From calibration and compensating of positional errors it is possible to reduce the effects of the volumetric errors in machines with axis of linear displacements as the CMMs and machine tools.
Size Determination of Immersed and Embedded Cylindrical Rods by Inversion of Acoustic Scattering Data
Authors: Mohammadreza Kari , Sadraei Masoumeh
Published: October 2015

In this paper, a new approach is proposed for nondestructive size determination of immersed and embedded cylindrical rods by inversion of acoustic scattering data. The normal mode expansion technique is used for modelling the scattered field. Also, the experimental backscattered field is measured using short pulse MIIR technique. The Genetic algorithm is the inversion technique used for measuring the diameters of the rods. The inversion technique matches the modelled and experimental scattered fields at resonance points, so the diameters of the rods can be estimated. The numerical results indicate that proper selection of resonance frequencies leads to accurate measurement of diameter. The proposed approach showed very good convergence and the results obtained were found to agree very well with available data.
Application of High-Strength Gradient Cutting Ceramics with a Multifunctional Coating for Heavy Machining of Hard-to-Cut Materials
Authors: Vereschaka Alexey Anatolevich , Mokritskii Boris Y. , Pustovalov Dmitriy A. , Vereschaka Anatoliy Stepanovich , Bublikov Jury I. , Litkin D.N.
Published: October 2015

The study deals with the challenge concerning the use of tools made of ceramics with nanostructured multilayer composite multi-component coatings produced through filtered cathodic vacuum-arc deposition for operation of severe machining of materials, including interrupted machining. The study shows the possibility for creating ceramic tools of new generation from high-strength gradient cutting ceramics (HGC-ceramics) of three-layer structure comprising a substrate based on carbide WC-TiC-Co and ceramic top layer based on Al2O3and Si3N4doped AlN and nanostructured multilayer composite multi-component coating of Ti-TiCrN-TiCrAlSiN type. The study presents the results of research on the optimization of composition of two-layer substrate and manufacture of high-strength gradient cutting ceramics (HGC-ceramics) with nanostructured multilayer composite multi-component coatings, as well as the results of laboratory and production certification tests of cutting properties of tools equipped with cutting inserts of two-layer HGC-ceramics with developed coating.
Improving Efficiency of End Mills by Deposition of Modifying Nano-Scale Multilayer Composite Coatings
Authors: Vereschaka Alexey Anatolevich , Mokritskii Boris Y. , Pustovalov Dmitriy A. , Vereschaka Anatoliy Stepanovich , Bublikov Jury I. , Oganyan Gaik V.
Published: October 2015

The study considers the challenge of improving the efficiency of end mills made of carbides through modification of physical and mechanical properties of tools by forming nanostructured multilayer composite coatings on its working surfaces with the use of filtered cathodic vacuum-arc deposition (FCVAD). The system and structure of three-component nanostructured multilayer composite modifying coatings for deposition on the working surfaces of the end mills are developed. The study presents the results of laboratory and industrial tests of end mills with coatings designed for conditions for rough and finish machining.
Tensile Behavior of Unidirectional Carbon Reinforced Composites for Aerospace Structures under Varying Strain Rates
Authors: Khan Haris A. , Nigar Mehr , Chaudhry Imran Ali
Published: October 2015

This paper focuses on progressive damage investigation and failure analysis of carbon fiber reinforced laminates under varying strain rates in tensile mode. Samples specimen prepared for experiments were made from unidirectional ply with 70/30 fiber-matrix volume fraction and cross-ply (0°-90°) balanced stacking. These laminates were subjected to uniaxial longitudinal tensile loading in a Universal Testing Machine (UTM) with varying strain rates. Results acquired from the experiments were used to plot stress versus strain curves for different strain rates. These plots were subsequently analyzed to investigate the effect of varying loading rates on the mechanical properties and failure behavior of these composites. Experimental data revealed a considerable increase in the tensile strength with increasing strain rate. The tensile modulus and strain to failure were also found to exhibit slight increase with the increasing strain rate.
Tool Wear of Aluminum/Chromium/Tungsten-Based-Coated Cemented Carbide in Cutting Hardened Steel
Authors: Wada Tadahiro , Hanyu Hiroyuki
Published: October 2015

An aluminum/chromium based coating film, called (Al,Cr)N coating film, has been developed. This coating film has a slightly more inferior critical scratch load and micro-hardness. Therefore, to improve both the scratch strength and micro-hardness of the (Al,Cr)N coating film, the cathode material of an alumi-num/chromium/tungsten target was used in adding the tungsten (W) to the cathode material of the alumi-num/chromium target. To clarify the effectiveness of the aluminum/chromium/tungsten-based coating film, we measured the thickness, micro-hardness and critical scratch strength of aluminum/chromium/tungsten-based coating film formed on the surface of a substrate of cemented carbide ISO K10 formed by the arc ion plating process. The hardened steel ASTM D2 was turned with the (Al,Cr,W)N, (Al,Cr,W)(C,N), (Al,Cr)N and the (Ti,Al)N coated cemented carbide tools. The tool wear of the coated cemented carbide tools was ex-perimentally investigated. The following results were obtained: (1) The micro-hardness of the (Al,Cr,W)N or (Al,Cr,W)(C,N), (Al,Cr)N coating film was 3110 HV0.25Nor 3080 HV0.25N, respectively. (2) The critical scratch load of the (Al,Cr,W)(C,N) coating film was 123 N, which was much higher than that of the (Al,Cr)N or (Ti,Al)N coating film. (3) In cutting the hardened steel using (Al,Cr,W)(C,N) and (Ti,Al)N coated carbide tools, the wear progress of the (Al,Cr,W)(C,N) coated carbide tool was almost equivalent to that of the (Ti,Al)N coated carbide tool. The above results clarify that the aluminum/chromium/tungsten-based coating film, which is a new type of coating film, has both high hardness and good adhesive strength, and can be used as a coating film of WC-Co cemented carbide cutting tools.
Application of Oyster (Anadara Inflata) Shell Chitosan as Adsorbent for Heavy Metal Cu(II) Ion
Authors: Hadi Saptono , Hastuti Budi , Setiawati Nurina Tulus
Published: October 2015

Research on the application of chitosan derived from oyster (Anadara inflata) shell as adsorbent for heavy metal Cu (II) has been conducted. Optimum conditions for adsorption, including pH, reaction time, and mass of adsorbent were investigated. Adsorption capability of Cu (II) by chitosan under those optimum conditions was subsequently evaluated by determining their adsorption isotherms and interaction mechanism. The results showed that the optimum condition for adsorption were pH 8, contact time 60 min, and mass of adsorbent 300 mg. Under those optimum conditions, chitosan has a high percentage removal of Cu (II) from aqueous solution, up to 70%. The adsorption process was well described as Langmuir isotherm and it is assumed that the interaction between Cu (II) and chitosan was based on chemical mechanism.
Wear Behaviour of Cryogenic Treated M2 Tool Steel under Dry Sliding Condition
Authors: Sonawane S.A. , Tripathi V.K. , Ambekar S.D.
Published: October 2015

The technique of cryogenic treatment of cutting tools is an inexpensive permanent treatment process that improves the physical and mechanical properties of materials such as metals, plastics and composites. It promotes the transformation of the retained austenite into martensite at cryogenic temperatures and also facilitates the formation of fine carbides in the martensite, thereby improving the wear resistance.This paper compares the wear behaviour of hardened and triple tempered AISI M2 high-speed steel and the same steel that was hardened and triple tempered in conjunction with a deep-cryogenic treatment at 88K for 16 and 24 hours. Test materials were subjected to wear tests on pin-on-disc machine in dry sliding condition. Equations are developed for predicting the wear resistance of M2 tool steel material. The hardness data wear loss and microstructure throw light on the improvement in wear resistance property of the M2 tool steel.It is demonstrated that the properties of the cryogenically treated samples are superior to those of conventionally treated. 24 hours cryogenically treated hardened and triple tempered M2 tool steel shows excellent wear resistance properties over 16 hours cryo-treated M2 and conventionally treated M2 tool steel material.
Experimental Determination of Tyre Lateral Force: Application to Tyre Cornering Stiffness
Authors: Georgieva Hristina , Kunchev Lilo
Published: October 2015

Tyre cornering stiffness is an important parameter of vehicle modelling and can be used to evaluate vehicle lateral stability and handling. This work presents the results of the measured tyre lateral force that was created by a tyre slip angle set up in advance. The obtained results permit to estimate the tyre cornering stiffness. The results have been realized with a tyre mobile tester.
Epoxy Resin as a Binder in the Preparation of Rutile Coated Electrodes
Authors: Lage Fernando C. , Oliveira Leandro S. , Franca Adriana S. , Bracarense Alexandre Q.
Published: October 2015

Coated electrodes are used in manual welding, with the coating being comprised of a variety of ingredients, including the binder, usually sodium or potassium silicate. In recent studies aiming at waterproof electrodes, the usual binders were successfully replaced by hydrophobic polymers. In this study, the use of epoxidized soybean oil (ESO) as well as a commercial epoxy resin (CER) as binders in electrode coating formulations was evaluated in order to verify their suitability as replacements for silicates. The produced electrodes were evaluated for the quality of the weld. Results showed that the use of a CER added of potassium feldspar resulted in favorable weld microstructure, with production of acicular ferrite and martensite elimination. ESO based electrodes still need to be improved through flux modification to reduce carbon and hydrogen content in the weld metal.
Research on Wear Mechanism of Solid Lubrication Bearing in Vacuum Environment
Authors: Lai Xiao Ming , Han Jian Chao , Gao Peng , Qu Jian Jun , Li Yun , Tan Chun Lin , Jiang Jiang
Published: October 2015

The wear mechanism of solid lubrication bearing in vacuum environment was researched. It experiment on the angular contact ball bearing of sputter-deposited MoS2 solid lubrication coating in bearing friction test device, and the time-varying characteristics of bearing temperature and vibration can be got. The MoS2 solid lubrication coating on bearing surface was gradually wear in the process of bearing rotation, and the temperature and vibration of bearing were increased. The transfer membrane was formation in bearing raceway with the increase of bearing rotation. The transfer membrane accumulation occurs due to uneven thickness of MoS2 solid lubrication coating, and the bearing produce serious vibration. Through the microstructure observation and energy spectrum analysis of the bearing surface, it finds there are pitting caused by fatigue wear and scratch caused by abrasive wear after test. The test result indicate that the wear mechanism of solid lubrication bearing in vacuum environment were fatigue wear of solid lubrication coating caused by steel ball circularly rolling and abrasive wear caused by steel ball sliding.
Experimental Investigation of Machining Factors in Metal Turning Operation Using Shainin’s Variables Search Method
Authors: Saikaew Charnnarong , Channongwang Theerawat , Kumpoo Teerapol , Chummuangpug Thichathorn , Leesai Manop
Published: October 2015

This paper aimed to investigate the machining factors influencing surface roughness and to obtain the appropriate turning operation of aluminum. The Shainin design of experiment method was used to investigate the effect of the four turning factors on surface roughness. Moreover, analysis of variance and multiple comparisons were used to obtain the appropriate turning operation of the significant factors. The results showed that spindle speed was the only significant factor affecting the average surface roughness with the appropriate turning operation of 1000 rpm used for reducing surface roughness of the machined part and tool wear.
Analysis of Buckling of Sandwich Plates with Viscoelastic Core Using Layerwise Theory
Authors: Ranjbaran Arash , Khoshravan Mohammad Reza , Kharazi Mahsa
Published: October 2015

Sandwich plates are one of the important components in construction of engineering and especially aerospace structures. In this paper, buckling analysis of sandwich plates was investigated experimentally and analytically using layerwise theory. The sandwich plate was rectangular and made of two composite laminates as skins and a viscoelastic core. The formulation was based on the first order shear deformation theory and the Rayleigh-Ritz method was used for approximating and determining the displacement field. The behavior of viscoelastic material modeled using Zener three-element model. The results obtained from layerwise theory compared with experimental results and showed good agreement. This study demonstrated that, layerwise theory could describe buckling behavior of sandwich plates with high accuracy and represents more realistic and acceptable description of behavior of the plates with much less computational cost.
Bespoke Part Library for an SME for Enhanced Design Efficiency
Authors: Barrans Simon , Eyre Gareth , Goddard Michael
Published: October 2015

In this paper the development of a company specific part library system is presented. The system is developed for an SME, Company A, that designs and manufactures industrial automation equipment. The part library system is shown to provide significant cost benefits to the design process within the company.
A Generalized Elasto-Plastic Micro-Polar Constitutive Model
Authors: Gori Lapo , da Silva Pitangueira Roque Luiz , Silva Penna Samuel , Fuina Jamile Salim
Published: October 2015

This paper summarizes the implementation of an elasto-plastic constitutive model for a micro-polar continuum in the constitutive models framework of the software INSANE (INteractive Structural ANalysis Environment). Such an implementation is based on the tensorial format of a unified constitutive models formulation, that allows to implement different constitutive models independently on the peculiar numerical method adopted for the solution of the problem. The basic characteristics of the micro-polar continuum model and of the unified formulation of constitutive models are briefly recalled. A generalization of the micro-polar model is then introduced in order to include this model in the existent tensor-based formulation. Finally, an enhanced version of the general closest-point algorithm, ables to manage the generalized micro-polar formulation, is derived. A strain localization problem modeling illustrates the implementation.
Aircraft Ditching Loads Simulation Tool
Authors: Bonanni Antonino , Vandewaeter Lorenz , Havill Caroline , Kanyoo Prin , Taunton Dominic , Blake James I.R. , Cropper Evelyn , Hancock Simon
Published: October 2015

The present work presents a novel methodology developed for calculating the steady loads acting on aircraft structures in the event of ditching in water. It represents the preliminary result of Stirling Dynamics as part of a NATEP research project. The overall objective of the project is to expand the capabilities of the Stirling Dynamics proprietary software SD-GLOAD (originally designed for ground and crash loads dynamic simulations) to aircraft ditching simulations. The methodology presented in this paper employs a Doublet Lattice Method (DLM) to calculate the steady pressure distribution acting on the submerged parts of the ditching aircraft. The proposed methodology is validated against a higher-fidelity CFD multi-phase model for a selected test-case and several ditching conditions.
Investigation of Vortex Structures for Supersonic Jet Interaction Flowfield
Authors: Beketaeva Asel , Abdalla Amr H. , Moisseyeva Yekaterina
Published: October 2015

The three-dimensional supersonic turbulent flow in presence of symmetric transverse injection of round jet is simulated numerically. The simulation is based on the Favre-averaged Navier-Stokes equations coupled with Wilcox’s turbulence model. The numerical solution is performed using ENO scheme and is validated with the experimental data that include the pressure distribution on the wall in front of the jet in the plane symmetry. The numerical simulation is used to investigate in detail the flow physics for a range of the pressure ratio . The well-known primary shock formations are observed (a barrel shock, a bow shock, and the system of λ-shock waves), and the vortices are identified (horseshoe vortex, an upper vortex, two trailing vortices formed in the separation region and aft of the bow shock wave, two trailing vortices that merge together into one single rotational motion). During the experiment the presence of the new vortices near the wall behind the jet for the pressure ratio is revealed.
Design of a Solar Powered, Unmanned, Low Altitude, High Endurance Airship
Authors: Sonmez Onur Sinan , Alemdaroglu H. Nafiz
Published: October 2015

This article presents the design of a low altitude long endurance solar powered unmanned airship. In the first part of the article, a brief introduction about the airships, their potential areas of usage, the advantages of using an unmanned air vehicle, and a comparison between unmanned counterparts will be given. In the second part, the design criteria and the general design specifications will be outlined briefly. During the design, emphasis is given on the general design parameters of the Lighter Than Air (LTA) vehicles. Lastly, the detailed design results, in order to reach the projected design parameters, have been presented.
Aircraft Configuration Improvement Study from Aerodynamic and Structure Standpoints
Authors: Fragola Barbosa Luciano Magno , de Freitas Pinto Ricardo Luiz Utsch , Oliveira Hargreaves Bernardo
Published: October 2015

In this work improvements on the geometry of a high aspect ratio aircraft wing are studied, in order to reduce the wing in-flight deformation, without changing the drag of the aircraft and without increasing the structural weight. For this, from a reference rectangular wing, one new wing with elliptical planform has been defined; and comparative analyses of loads and structural deformation have been made for the wings considered: the original rectangular wing and the new corresponding elliptical wing. The aerodynamic analysis is based on the lifting line approach. A computer routine is made by the authors based on this approach, to obtain both induced drag values and the load distribution of the two wings, the original one and the corresponding elliptical. Based on the loads, spars for the two wings have been defined, and in order to evaluate the vertical displacements in flight, a finite element routine have been used. The main result of this study is the comparison of the deformation of wings considered, subjected to the same load factor, and for the same aircraft mass. The results obtained are encouraging for further developments using the present methodology.
Performance Evaluation of a Variable Geometry Gas Turbine in a CHP Plant
Authors: Tesfamichael Baheta Aklilu , Gilani S.I. , Sulaiman Shaharin Anwar
Published: October 2015

This study is to develop mathematical models and evaluate the performance of a gas turbine with variable geometry compressor working in a CHP plant. A single shaft gas turbine plant can maintain the exhaust gas temperature if the load is not below 50 % of the full load by simultaneously regulating the compressor variable vanes position and fuel flow. For load less than 50% the engine is running to meet the power demand. This is achieved by controlling the fuel flow and air bleed at the downstream of the compressor to avoid surge formation while variable vanes are opened fully. To accommodate change of compressor parameters during variable vanes re-stagger correction coefficients are introduced. A behavior of a 4.2 MW gas turbine performance was evaluated. The effect of variation of load and ambient temperature on the gas turbine specific fuel consumption, temperature, pressure ratio, variable vanes opening and efficiency were examined. Comparison between the field data and simulation results demonstrate good agreement. The off-design calculation was done by in-house developed program in MATLAB environment.
A “Laminar + Transition Criteria” Model for Hypersonic Three-Dimensional Boundary Layer Transition Prediction
Authors: Zhou Ling , Yan Chao , Hao Zi Hui , Kong Wei Xuan
Published: October 2015

A “laminar + transition criteria” model utilizingReθ/MeandReCFcriteria in conjunction with an intermittency functionΓis developed in this paper. With pretreated computational grid and total enthalpyh0=(h0,∞)maxcriteria the boundary layer edge and crossflow velocity can be obtained by using parallel methodology. Validation is accomplished via HIFiRE-5 and a blunt cone with small angle of attack. Results show that computedReθ/MeandReCFdistributions are similar to theN-factor for streamwise instability and crossflow instability from linear PSE methods. The shape and trend of transition regions predicted by the “laminar + transition criteria” model in HIFiRE-5 and blunt cone are in good agreement with the experiment and DNS. However, for the transition induced by inflection point on streamwise velocity profiles, using criteria related to boundary layer thickness is inappropriate and can predict transition onset prematurely.
Gantry Robot for Mobile Observation
Authors: Jamaludin Syukrul Hassani , Mansor Muhammad Naufal , Junoh Ahmad Kadri , Idris Azrini
Published: October 2015

A gantry robot consists of a manipulator mounted onto an overhead system that allows movement across a horizontal plane. Gantry robots are also called Cartesian or linear robots. They are usually large systems that perform pick and place applications, but they can also be used in welding and other applications like for observing the behavior of patient in hospital wards. Fast motion of a gantry robot is usually associated with undesirable induced oscillations of the suspended object. Because of these oscillations, gantry robot maneuvers are performed slowly contributing to low site efficiency and high transportation costs. These undesirable oscillations can be minimized at reasonably high travel speeds by designing effective controllers. To solve this problem precaution should also be considered as not to use unbalanced structure and also the most important was the mechanism of the robot. The robot structure requires high stability so that when the camera housing is positioned to the required locations it will not disturbed and ensure safety to the patient.
Combined Compliance Method of the Variable Cross Section Flexure Hinge and its Verification
Authors: Liu Qing Ling , Wang Xing Xin
Published: October 2015

Flexure hinge is the most basic compliant structure, the compliance is one of the important performance parameter. The structure characteristics is analysed and the new method used for calculating the compliance is performed in this paper. Based on the structure characteristics analysis of the right circle, corner filleted and elliptical flexure hinge (symmetric and non-symmetric), half flexure hinges are analysed and the compliance formulas are given by selecting the reasonable integral variable. The combined compliance formulas of 12 kinds flexure hinge (simple, hybrid (symmetric,non-symmetric)) are obtained by half different types of flexure hinge being combined. The right circular flexure hinge, right circular elliptical hybrid flexure hinge and non-symmetric elliptical flexure hinge are selected and their compliance are calculated with the formulas in this paper and in literatures, which results indiceted the validity and correctness of the combined compliance method.
Cascading Analysis Using Discrete Element Method in Rotary Drum Coolers
Authors: Huebner Rudolf , Barreto Pereira Lúcio , Nacife Carneiro Rafael
Published: October 2015

Discrete Element Methods have been used extensively in processes involving flow behavior where modeling the individual particles is of particular interest. A rotary cooler is an application of one such process. Although the current analysis can be used to any type of rotary cooler or rotary dryer, this work is focused on the analysis of particles falling from lifters in a planetary rotary cooler used in the production of clinker and installed at the outlet of a rotary kiln. Clinker is the main raw material used to manufacture cement. The objective of this work is to model the particle distribution inside the equipment due to different types of lifters and process conditions. Some of the parameters evaluated demonstrate that the tangential restitution coefficient and the Young’s modulus do not influence the results. However, a rolling friction coefficient on the order of 10-3 is required to represent a real operating condition. The results produce cascading similar to that of experimental observations reported in literature. Both our results and previously reported data display two distinct areas in the rotary drum, one mainly composed of material (the curtain area) and the other lacking material (the air area).
Development of Simulator for Intelligent Autonomous Underwater Vehicle
Authors: Gurenko Boris , Fedorenko Roman , Beresnev Maksim , Saprykin Roman
Published: October 2015

Testing and debugging of real equipment is a time consuming task. In particular, in the case of marine robots, it is necessary each time to carry out the transportation and deployment of a robot on the water. Experiments with not yet fully functional prototype of marine robot equipped with expensive hardware is in the meantime very risky. Therefore, the use of simulators is affordable way to accelerate the development of robotic systems from the viewpoint of labor effort and cost of experiments. This paper presents a simulator specifically designed for autonomous unmanned underwater vehicles.
Estimation of a Pipe’s Features with In-Pipe Robot
Authors: Park Jung Wan , Jeon Won Seok , Yang Hyun Seok
Published: October 2015

Most of pipelines are installed under the ground, so maintaining is one of the most critical issue. Furthermore, their own locations are difficult to be identified because of its environment. For those reason, identifying the location of pipelines is widely under the research with in-pipe robots. Most methods estimate the heading direction of pipe robots as the axial direction of pipelines. However, more detail research about the axial directions of pipelines is necessary because the defined directions are not always aligned with the heading direction of pipe robot. Therefore, this paper described the estimating method of pipeline radius and its axial direction relative the robot. The relative direction and radius of a pipe are estimated from location of contact points which is determined based on geometry. Geometric equation contains highly nonlinear term, so those are obtained by the numerical form instead of closed form. The suggested method is verified by an experiment approach. Since the real relative axial direction is hard to detect, the slope of pipes are computed from estimated value and inertial measurement unit attached to the robot. Estimated radius and slope have some error in discrete curved pipe, but estimated values are well matched under straight pipes condition.
A Numerical Simulation of Micro Bionic Fish in Vessel
Authors: Yang Chao , Zhu Fu Xian , Zhou Jin Yu , Chen Ju Fang
Published: October 2015

The work presented a research method of using the external magnetic field to do a numerical simulation of micro bionic fish. The fishtail skeleton was made of alloy sheet and the fish tissue was stuck on the alloy sheet with giant magnetostrictive material (GMM). Then the mechanical model of bionic fish was established. By controlling the swaying of fishtail through external magnetic frequency adjustment, it is possible to make the fish move about just like a natural fish. The statistics show that the average driving force when the bionic fish is switched on largely depends on the material parameter, blood viscosity and external magnetic frequency. The average driving force will increase with the growing elasticity modulus (EM) of fishtail material and blood viscosity. The bionic fish can get a quite large driving force particularly when the external magnetic frequency is getting close to the natural frequency of the system. Thus, these findings can serve as a major train of thought and gist for the design and control of micro bionic fish in vessel.
Design and Optimization of a PKM for Micromanipulation
Authors: Righettini Paolo , Lorenzi Vittorio , Zappa Bruno , Ginammi Andrea , Strada Roberto
Published: October 2015

The actual miniaturization trend, present in several industrial sectors, requires high performance capabilities in micromanipulation and assembly. A complete automation of these operations, by means of robots, could result in a significant cost cut in the final product.
In this work we present the mechatronic design and optimization of a 3 d.o.f. Delta type PKM for micromanipulation. Starting from a reference task (pick and place with high stroke rate) the optimal links length has been determined by considering several kinematic performance indexes; afterwards the actual link sizing has been performed considering dynamic loading, also taking into account the effect of the links flexibility on end effector trajectory.
A direct drive actuation has been chosen, where the motor sizing has been performed to satisfy several criteria: maximum and r.m.s. torque and maximum speed. The motor selection has been speeded up querying a database built by collecting data from the catalogues of several producer. Furthermore robot joints have been carefully designed in order to reduce backlash and friction.
Low Dosage Gamma Irradiation of Poly(glycerol sebacate)-co-lactic Acid Utilizing Methyl Methacrylate Crosslinker
Authors: Magdaluyo Eduardo R. , Medrano Jerilene L.
Published: October 2015

The use of low dosage gamma radiation and crosslinker was explored to reduce time and energy requirements for the crosslinking of the biomedical polymer poly(glycerol sebacate)-co-lactic acid (PGS-co-LA) and to determine the effect of these parameters on the polymer’s properties. Curing time was effectively reduced to less than 2 hours from the typical 48 hours required by thermal curing. Analysis using infrared spectroscopy identifies the bonds forming PGS-co-LA and confirms the formation in all low radiation dosage settings and crosslinker amounts. Increasing the amount of crosslinker did not change the polymer’s thermal properties significantly whereas increasing the radiation dosage from 5 kGy to 10 kGy resulted to more negative value of melting temperature and increase in heat of fusion. The sample with the highest amount of crosslinker irradiated at the lowest level of radiation dosage has the least negative melting temperature and lowest heat of fusion
Autonomous Area Mapping with Low Cost Hovercraft Platform
Authors: Dalloz Loïc , Brand Alexandre , Chiniah Ivan , Beaumale Damien , Commun Manon
Published: October 2015

In this paper, the possibility to build a low cost hovercraft platform with easily accessible materials and able to perform autonomous ground mapping is discussed. To do so, platform design is presented with proportional motors and construction module. The computing system is integrated to manage the platform displacement. Algorithms are used to counteract every constraint existing in this kind of vehicle such as low ground interaction and motors feedback, based on previous research on hovercraft stabilization. The mapping system which includes a camera and a laser is discussed in detail, and final mapping and exploration is computed with inspiration from mapping research.
Knowledge Push Technology for Complex Mechatronic Products Design Based on Ontology and Variable Precision Rough Set
Authors: Wang Fa Lin , Guo Yu , Liao Wen He , Wu Bao Sheng
Published: October 2015

In this paper, we present a new knowledge push technology for complex mechatronic products design based on ontology and variable precision rough set (VPRS). Ontology can explicitly represent knowledge semantics and let designers exchange knowledge about design and the product development process; while using the knowledge reduction method based on the VPRS method, the design knowledge repository is simplified and design rules also be distilled from the reduct design knowledge repository. On the basis of the above approach, multiple designers can efficiently share design knowledge and can obtain appropriate design knowledge during all design processes. Finally, a case is employed to validate the proposed method of this paper.
The Second Lyapunov Function Method in Construction of Control Systems with the Increased Potential of Robust Stability in the Class of Catastrophe “Hyperbolic Umbilic”
Authors: Mukataev Nurlan , Beisenbi Mamyrbek
Published: October 2015

The current article introduces a new method of construction of control systems for objects with uncertain parameters in the form of three-parameter structurally stable mappings from the theory of catastrophe, allowing to synthesize the highly effective control systems, which demonstrate the extremely wide range of robust stability. The research of robust stability of control systems is based on a new approach to post-rhenium of the A.M Lyapunov’s functions. The method of creation of control system with the increased potential of robust stability is stated. It could be concluded that the application of the suggested approach may assure asymptotically stable invariant states for the system in both negative and positive regions of variations of uncertain parameters.