bluuebunny/crossref_metadata_2025 huggingface dataset:
Novel Controlled-Velocity Wind Turbine Testing Apparatus to Simulate Turbulent, Non-Return Flow
Authors: Ressler Corey P. , Hilbish James , French Jesse J.
Published: October 2014

This paper presents the work done by the authors to analyze the method of performance characterization of a 100W scale vertical axis wind turbines using a controlled-velocity test apparatus. The design of the power transfer system containing a gearbox and generator requires test data to determine the peak and operating range of wind speed, corresponding to RPM and torque. Multiple methods of turbine testing were considered, including in situ, wind tunnel, and control-velocity. Controlled-velocity, a method where the turbine is moved through a fluid, was selected based on lack of test location wind speeds or access to a wind tunnel of sufficient size. The test apparatus is designed to be effective for VAWT turbines of a diameter range from 1.45 to 4.2 meters in a wind velocity range of 1 to 17 m/s. This covers a Reynolds number range between (2.5 × 10^5 < Re < 4.2 × 10^6). A change from previous control-velocity test apparatus is the use of a separate truck and trailer compared to a flatbed truck, which allows greater distance between the truck cab and the turbine, to decrease any flow interference of the cab. This previous work and testing has shown to be a valid test method in that the turbine is in similar turbulent conditions as near the ground and buildings which the turbine is designed for. The main advantage of this test apparatus is the ability to test turbines in a region with low average wind speeds and minimum infrastructure.
Developing an Inverse Heat Conduction Analysis Tool for Real Time Heat Flux Estimation in Directional Flame Thermometer Application
Authors: Najafi Hamidreza , Woodbury Keith
Published: October 2014

Accurate measurement of heat flux and temperature can significantly affect the energy usage in several industrial applications, including furnace operation, metal processing, fire safety tests and more. Directional Flame Thermometers, or DFTs, offer the ability to use both temperature and heat flux measurements for furnace control. Currently, analysis of dynamic temperature data from the DFTs to compute heat flux information must be performed off-line at the conclusion of data-gathering by using software tools such as IHCP1D. Availability of a near real-time algorithm for accurate reduction of the data will allow for continual monitoring of the furnace during operation. This will result in better control over the process and significant savings in energy and cost. In this paper, a filter form of the inverse heat conduction algorithm is developed for utilization in DFTs. The algorithm is based on linearized solutions of the direct heat equation, and non-linear effects introduced by temperature dependent thermal properties are accounted for by interpolating of the resulting filter coefficients. The developed method is tested through several numerical experiments and also ANSYS model. A graphical user interface is developed in LabVIEW to provide a friendly interface for the end user. The temperature data measured by thermocouples on the DFT are transmitted to the computer through data acquisition card and the developed tool in LabView display the heat flux in a near real time fashion.
Hot Corrosion Studies Using Electrochemical Techniques of Alloys in a Chloride Molten Salt (NaCl-LiCl) at 650°C
Authors: Gomez Judith C. , Tirawat Robert , Vidal Edgar E.
Published: October 2014

Next-generation solar power conversion systems in concentrating solar power (CSP) applications require high-temperature advanced fluids in the range of 600° to 900°C. Molten salts are good candidates for CSP applications, but they are generally very corrosive to common alloys used in vessels, heat exchangers, and piping at these elevated temperatures. The majority of the molten-salt corrosion evaluations for sulfates with chlorides and some vanadium compounds have been performed for waste incinerators, gas turbine engines, and electric power generation (steam-generating equipment) applications for different materials and molten-salt systems. The majority of the molten-salt corrosion kinetic models under isothermal and thermal cyclic conditions have been established using the weight-loss method and metallographic cross-section analyses. Electrochemical techniques for molten salts have not been employed for CSP applications in the past. Recently, these techniques have been used for a better understanding of the fundamentals behind the hot corrosion mechanisms for thin-film molten salts in gas turbine engines and electric power generation. The chemical (or electrochemical) reactions and transport modes are complex for hot corrosion in systems involving multi-component alloys and salts; but some insight can be gained through thermochemical models to identify major reactions. Electrochemical evaluations were performed on 310SS and In800H in the molten eutectic NaCl-LiCl at 650°C using an open current potential followed by a potentiodynamic polarization sweep. Corrosion rates were determined using Tafel slopes and the Faraday law. The corrosion current density and the corrosion potentials using Pt wire as the reference electrode are reported.
Mixed-Mode Hygrothermal Fracture Analysis of Orthotropic Functionally Graded Materials Using J-Integral
Authors: Topal Serra , Dag Serkan
Published: October 2014

Functionally graded materials (FGMs) are multi-phase inhomogeneous composites, possessing smooth spatial variations in certain physical properties of the constituents. Depending on the types of the constituent materials used in the processing of orthotropic FGMs, the influences of thermal and hygroscopic loadings could be rather significant. This study is directed towards developing a new computational fracture analysis technique for orthotropic FGMs that are under mixed-mode hygrothermal loading. The method is based on the use of the J-integral in conjunction with the asymptotic crack tip displacement fields. Developed computational technique is integrated into a finite element analysis software. Parametric analyses are carried out by considering an inclined edge crack in an orthotropic FGM layer that is subjected to the influence of hygrothermal loading. In order to be able to verify the proposed method, obtained results are compared to those computed via displacement correlation technique (DCT). Comparisons demonstrate that proposed technique leads to numerical results of high accuracy. Further results are provided to illustrate the influences of crack inclination angle and geometry on the temperature and the specific moisture concentration fields; and the modes I and II stress intensity factors.
Engine Mount Vibration Sensitivity to Stiffness and Mass Properties of Major Components
Authors: Kagnici Fatih
Published: October 2014

In order to have an optimized NVH design concept, the design engineers must exchange during the development a lot of attributes that together defines the new engine NVH performance. Moreover, each engine NVH system performance is dependent of many variables. In this respect, 6-Sigma methodology (DMAIC and DCOV) is an excellent tool to support engineers to evaluate systems variables and achieve the required performance.

Engine mount brackets’ vibrations have high priority for the NVH performance of the powertrain. Effects of major components on the engine mount vibrations come up as a major topic whenever an error state takes place and improvement is required. This study aims to identify the effect of engine block, ladderframe, head and transmission stiffness and mass properties on 2EO acceleration levels of the 4 cylinder engine power train. Dynamic analysis will be performed under the kinematic engine loadings. There are 2 steps for identifying the objective. The first step is to eliminate the factors which has not significant main and cross effect on engine mount vibrations.

Full factorial DOE runs with two levels are performed for this purpose. Hyperstudy tool is used for the DOE design, simulation automation and post processing. After defining the effective factors, 256 Latin Hypercube DOE runs are performed to obtain response surfaces and meta–model. DOE runs are done in Hyperstudy, results are exported to enCORE and transfer functions are calculated by Kriging method.

According to the results, a proposed course of action for engine mounts’ accelerations DOE study is prepared and a methodology for this course is executed.
Dynamic Behavior and Synchronization of an Automobile as a Complex System
Authors: González-Cruz Claudia A. , Jáuregui-Correa Juan C. , López-Cajún Carlos S. , Sen Mihir
Published: October 2014

A complex system is composed of many interacting components, but the behavior of the system as a whole can be quite different from that of the individual components. An automobile is an example of a common mechanical system composed of a large number of individual components that are mechanically connected in some way and hence transmit vibrations to each other. This paper proposes a variety of inter-related analytical tools for the study of experimental data from such systems. In this work, experimental results of accelerometer data acquired at two locations in the automobile for two different kinds of tests are analyzed. One test is the response to impact on a stationary vehicle, and the other is the road-response to the vehicle being driven on a flat road at different speeds. Signals were processed via Fourier and wavelet transforms, cross-correlation coefficients were computed, and Hilbert transforms and Kuramoto order parameters were determined. A new parameter representing synchronization deficit is introduced. There is indeed some degree of synchronization that can be quantified between the accelerations measured at these two locations in the vehicle.
Design and Construction of an Experimental Test Rig for Hydraulic Turbines
Authors: Ayli Ece , Kavurmaci Berat , Celebioglu Kutay , Aradag Selin
Published: October 2014

Every turbine for every hydroelectric power plant is unique; therefore its model has to be designed using state of the art design techniques and tested before the actual prototype which is costly, is manufactured. In this study, the details of the design and construction of a hydroturbine test facility at TOBB University of Economics and Technology are explained. The facility will be used to test hydroturbine models up 2MWs of power simulating turbine prototypes. The performance and cavitation tests of the turbines will be performed utilizing this facility according to International Electrical Commission (IEC) standards. The test facility is 19 meters long with a base area of around 600 meter squares. The hydraulic analysis of the designed set-up is performed using a system where valves, pipes, structures, water records and connections form an intelligent system, same with the experimental facility. According to the results, system performance is checked, alternative designs are evaluated and operating strategies are defined by minimizing the losses.
Influence of Installation Tension on Transmission Error due to Resonance in a Synchronous Belt
Authors: Kagotani Masanori , Ueda Hiroyuki
Published: October 2014

In synchronous belt drives, transmission error is generated due to resonance of the belt spanning the driving and driven pulleys when the transverse natural frequency of the belt approaches the meshing frequency of the belt and the pulley teeth. The behavior of the transmission error caused by resonance has been assumed to be dependent on the installation tension. In the present study, the influence of installation tension on the transmission error in a synchronous belt drive was experimentally investigated for a case in which first mode vibration due to resonance was induced in both the upper and lower spans. In addition, an analysis of the transmission error based on the experimental results was carried out. A transmission error contains two components: one with a period equal to the pitch of the pulley, and the other with a period of half the pulley pitch. Good agreement was found between the calculation and experimental results, thus confirming the validity of the analysis method. For a fixed pulley speed, the transmission error was largest when the installation tension was applied at a position where the displacement of the upper span was equal to that of the lower span. When the installation tension was varied and the pulley speed was adjusted so that the belt experienced resonance, the transmission error decreased with an increase in installation tension.
Effect of Loading Rate on the Stress Distribution on Heavy Truck Chassis
Authors: Cinar Ali
Published: October 2014

In this study we discuss the effect of the loading rate on the distribution of stresses in heavy truck chassis. Stress values on the critical components have been compared with respect to the loading rate under same load magnitude. The results show that loading rate is an important parameter in engineering; using higher loading rates leads to higher fluctuations in the predicted stresses. Our investigation is purely numerical and is based on the commercial finite element software Abaqus / Explicit.
In-Plane Thermal Residual Stresses in Functionally Graded Plates
Authors: Apalak M. Kemal , Demirbas M. Didem
Published: October 2014

This study addresses in-plane thermal residual stresses in two-dimensional functionally graded plates under a constant in-plane heat flux. The plate material properties vary with a power law along two in-plane directions not through the plate thickness. The transient heat conduction and Elasticity’s Navier equations describing the two-dimensional thermo-elastic problem were discretized using the finite-difference method, and the set of linear equations was solved using the pseudo singular value method. The in-plane transient distributions of temperature, displacement, stress and strain components were determined, and the two-dimensional exponents and directions of compositional gradient were investigated in terms of their effects on the stress and strain distributions in both plates. The exponent and direction of the compositional gradient affected the peak in-plane strain and stress levels; therefore, the stress and strain distributions can be relieved by arranging the exponent and directions of the compositional gradient.
Kinematics and Stiffness Modeling of a 4-DOF Parallel Robot for Schönflies Motion Generation
Authors: Bai Shaoping , Andersen Lasse Køgs , Mølgaard Carsten Rebbe
Published: October 2014

This work deals with the design of parallel robots for the generation of pick-and-place operation, or Schönflies motion. The aim is to develop a robot with workspace optimized for fast pick-and-place operations, namely, a robot with a superellipsoidal reachable volume, which suits best for the pick-and-place operations on conveyers, where robots’ working areas are nearly rectangular.

In this paper, the kinematics and stiffness modeling of the new robot are presented. A method of stiffness modeling by means of Castigliano’s Theorem is developed. Using the new method, the stiffness of the robot is analyzed. The results are compared with FEA simulation, which shows a good agreement between the results. The method is finally applied to the engineering design of the new robot for enhanced static and dynamic performance.
Image-Based Versus Signal-Based Sensors for Machine Fault Detection and Isolation
Authors: Fernando Heshan , Chauhan Vedang , Surgenor Brian
Published: October 2014

This paper presents the results of a comparative study that investigated the use of image-based and signal-based sensors for fault detection and fault isolation of visually-cued faults on an automated assembly machine. The machine assembles 8 mm circular parts, from a bulk-supply, onto continuously moving carriers at a rate of over 100 assemblies per minute. Common faults on the machine include part jams and ejected parts that occur at different locations on the machine. Two sensor systems are installed on the machine for detecting and isolating these faults: an image-based system consisting of a single camera and a signal-based sensor system consisting of multiple greyscale sensors and limit switches. The requirements and performance of both systems are compared for detecting six faults on the assembly machine. It is found that both methods are able to effectively detect the faults but they differ greatly in terms of cost, ease of implementation, detection time and fault isolation capability. The conventional signal-based sensors are low in cost, simple to implement and require little computing power, but the installation is intrusive to the machine and readings from multiple sensors are required for faster fault detection and isolation. The more sophisticated image-based system requires an expensive, high-resolution, high-speed camera and significantly more processing power to detect the same faults; however, the system is not intrusive to the machine, fault isolation becomes a simpler problem with video data, and the single camera is able to detect multiple faults in its field of view.
Molecular Dynamics Simulations of Rough Contact With Fractal and Statistical Surface Generation
Authors: Solhjoo Soheil , Vakis Antonis I.
Published: October 2014

Many studies on the contact of tribo-surfaces with nanoscale roughness adopt simplified deterministic surface topographies, which lend themselves to analytical solutions for the contact forces. More elaborate approaches that use, for example, fractal formulations are inherently more difficult to analyze but are increasingly used in tribological research. In this paper, molecular dynamics is used to simulate the three-dimensional contact between atomically rough surfaces of fcc-Nickel. Two methods are used to generate the surface roughness: fractals and a statistical approach utilizing spherical asperities. The tribo-surfaces are compressed with normal pressure and the results are compared for each method of rough surface representation. The two methods yield very similar results for the case of isotropic, Gaussian roughness.
Energy Audits in the Service Sector Buildings
Authors: Zanfardino Antonella , Andreassi Luca , Martini Fabrizio , Ubertini Stefano
Published: October 2014

In the last decade, the service sector had a very rapid growth, due to the so-called “tertiarisation” of the economy. Accordingly, the energy consumption, mainly attributable to public and private buildings, is rapidly growing, thus making buildings energy saving one of the main issues of the energy policy at regional, national and international levels.

To this aim, we developed an effective methodology to improve energy efficiency of the service sector buildings. This may represent a handy great opportunity to save natural and economic resources, especially where the buildings structure and the technical systems are old, the maintenance activities are not carefully carried out or a systematic energy management is not applied. Nevertheless, actions in this direction are often considered too expensive and complicated, if compared with residential energy optimization, because of the big extension, the variety of activities and the high number of occupants typical of the service sector buildings. The developed approach for energy audits aims to investigate the energy aspects of existing non-domestic buildings in a structured way, in order to clearly identify their energy saving potential and to improve their energy performances. The main goal of the study is defining a general methodology to analyze the current energy use and consumption considering a limited number of their peculiar elements such as dimensions, activities, users behavior, technical systems data and energy bills. Furthermore, these informations are completed by an appropriate energy measuring campaign. All the possible energy uses in service buildings are taken into account (i.e. lighting, ventilation, air conditioning, hot water production). The results obtained from the analysis allow to evaluate a global level of building energy efficiency, and to identify those single areas, specific systems or everyday activities where energy is wasted. These considerations also provide basis for programming cost-effective energy saving action plans.

The effectiveness of the proposed methodology is demonstrated through a case study for an Administrative Center building in Rome, Italy. Results demonstrate the methodology reliability and the cost reduction potentialities.
Film/Substrate Adhesion Assessment by Scratch Tests Performed With Different Indenters
Authors: Le Houérou Vincent , Jacomine Leandro , Gauthier Christian
Published: October 2014

In most cases, scratching of the surface of a polymeric glass elicits brittle behavior and industrial solutions like coating have been successfully used to improve the scratch resistance. The origin of the success of the coating technique is still of great research interest since one of the limitations of this technique is the risk of cracking and chipping. In terms of interfacial adhesion characterization, a wide variety of methods have been used to assess this property of material systems. Nevertheless, the adhesion of coatings still remains to be successfully determined in a test which can reproduce the damage undergone by the coated surface during its real lifetime. In this context, scratch test constitutes a good candidate. The present study deals with the scratching technique as an interfacial adhesion measurement in coated systems.

Using a single-asperity scratching device allowing in-situ observation of the scratch, the fracture of a thin nano-composite coating deposited on its substrate was investigated under different conditions of temperature and scratching speed. Four types of fracture kinetics were observed depending on these two variables. One of these exhibits a stable blister growth at the same speed as the movement of the indenter over hundreds micrometers. This slow and extensive growth of a blister was obtained at 80 °C at a scratching speed of 10 μm/s. When the blister has reached a certain size, it propagates with the indenter without increasing further in size: it constitutes the steady state blister growth.

A variational form of the energy balance of a blistering process is proposed, which permits to assess the adhesion of the system. Actually, the energy spent in the delamination process can be determined by following the delaminated area during the blistering process with regard to the scratching distance. The main difficulty is to estimate the energy dissipated in plastic flow. Different tests were conducted with various indenters: spheres with different radius and roughness. Thanks to this multi-criterion approach, it was possible to fit a unique value of the adhesion in the case of experimental stable blistering growths. The results are discussed with regard to reliability and probe characteristics.
Experimental and Numerical Study of Counter-Current Flow in a Vertical Pipe
Authors: Besagni Giorgio , Guédon Gaël , Inzoli Fabio
Published: October 2014

Counter current flow is encountered in a wide variety of industrial applications ranging from flows in nuclear reactors to process flows in chemical reactors. This paper describes experimental and numerical results obtained in a circular column of 240 mm inner diameter with two inner pipes. The counter current flow studied concerns an upward flow of air and a downward flow of water at ambient temperature and pressure. The following range of operating conditions is analyzed: superficial air velocities up to 0.25 m/s and superficial water velocities up to 0.04 m/s, corresponding to global void fractions up to 27.7%. The experimental investigations concerns (i) flow visualization, (ii) local data from a double optical probe and (iii) global void fraction data. Images obtained from an optical camera are used to observe the general flow pattern and to support the boundary conditions of the numerical simulations, in terms of average bubble diameter. Data obtained from the double optical probe are used to study local flow characteristics. The gas disengagement technique is used to obtain the global void fraction over a range of superficial air velocities for the validation of the numerical method. Numerical calculations are performed with an Eulerian two-fluid model using the commercial code ANSYS Fluent Release 14.5.7 and results are compared with experimental data. The effects of bubble diameter and various interfacial drag coefficients are studied. The formulation of the drag coefficient is found to have significant effects on the global void fraction predictions. However, using merely the drag law, numerical results are inaccurate.
Tribological Study of PMMA/Carbon Nanocomposites for Antifriction Coatings
Authors: Al-Kawaz A. , Rubin A. , Janowska I. , Pham-Huu C. , Mésini P. , Gauthier C.
Published: October 2014

The basics of antifriction coatings is to lower the frictional response of a surface. The coated material should either lower the interfacial shearing or increase stiffness of the surface. The latter should be reached by using carbon nano-fillers embedded in a polymer matrix. We choose PMMA as a matrix. The objective of this study is to gain knowledge on the influence of carbon nano-fillers on the surface response of PMMA nano-composites.
Vibration Isolation by Compliant Sensor Mounting Applied to a Coriolis Mass-Flow Meter
Authors: van de Ridder L. (Bert) , Hakvoort Wouter B. J. , van Dijk Johannes
Published: October 2014

In this paper a vibration isolated design of the Coriolis Mass-Flow Meter (CMFM) is proposed, by introducing a compliant connection between the casing and the tube displacement sensors with the intention to obtain a relative displacement measurement of the fluid conveying tube, dependent on the tube actuation and mass-flow, but independent of casing excitations.

Analyses are focussed on changing the transfer function of support excitations to the relative displacement measurement. The influence of external vibrations on a compliant sensor element and the tube are made equal by tuning the resonance frequency and damping of the compliant sensor element and therefore the influence on the relative displacement measurement is minimised. Based on simulation results, a prototype is built and validated.

The validated design show a 20dB reduction of the influence of external vibrations on the mass-flow measurement value of a CMFM, without affecting the sensitivity for mass-flow.
Airfoil Shape Design via Elastic Surface Inverse Design Method
Authors: Nili-Ahmadabadi M. , Safari M. , Ghaei A. , Shirani E.
Published: October 2014

In this research, a novel inverse design algorithm called, Elastic Surface Algorithm (ESA), is developed for viscose and inviscid external flow regimes. ESA is a physically based iterative inverse design method that uses flow analysis code to estimate the pressure distribution on the solid structure, i.e. airfoil, and a 2D solid beam finite element code to calculate the deflections due to the difference between the calculated and target pressure distribution. The proposed method is validated through the inverse design of three different airfoils. In addition, two design examples are presented to prove the robustness of the method in various flow regimes. Also, the convergence rate of this method is compared with flexible membrane method (MGM) and Ball-Spine Algorithm (BSA) methods in inviscid flow regime. The results of this study showed that not only the ESA method is an effective method for inverse design of airfoils, but also it can considerably increase the convergence rate in transonic flow regimes.
Programmable Support Functions to Assist Process Planning for Aeronautical Parts Manufacturing
Authors: Fountas Nikolaos A. , Stergiou Constantinos I. , Vaxevanidis Nikolaos M.
Published: October 2014

Despite the fast development and the continuous evolution of computer-aided systems for product design, analysis and manufacturing, an unlinked gap appears between the interfaces of computer-aided design (CAD) and computer-aided process planning (CAPP) modules. Various CAPP systems have been built to address this problem and forward a “passage” to link the design phase and the planning of manufacturing processes; hence, providing precise technical instructions in the shop-floor. To support the manufacturing trends and contribute to the research efforts for the realization of precise, reliable and efficient process plans, a set of programmable support functions are presented in the form of an object-oriented software application that enable process planners to produce accurate process plans for aircraft parts and components.
PCL/Eggshell Scaffolds for Bone Regeneration
Authors: Viana Tania , Biscaia Sara , Almeida Henrique A. , Bártolo Paulo J.
Published: October 2014

Eggshell (ES) is one of the most common biomaterials in nature. For instance, the ES represents 11% of the total weight of a hen’s egg and it is composed of calcium carbonate, magnesium carbonate, tricalcium phosphate and organic matter. Hen ES are also a major waste product of the food industry worldwide. Recently, ES have been used for many applications such as coating pigments for inkjet printing paper, catalyst for biodiesel synthesis, bio-fillers for polymer composites and matrix lipase immobilization. It is also considered a natural biomaterial with high potential for the synthesis of calcium enriched implants that may be applied in tissue engineering applications, such as bone regeneration. The aim of this research regards the production of poly(ε-caprolactone) (PCL) scaffolds enriched with hen ES powder for bone regeneration applications, using an extrusion-based process called Dual-Bioextruder. The main objective is to investigate the influence of the addition of ES powder on the PCL matrix. For this purpose the structures were characterised regarding morphological and chemical properties. Morphological images of the PCL scaffolds enriched with hen ES, demonstrated the interconnectivity of the pores within the scaffold and revealed that the addition of the ES powder combined with the screw rotation velocity has a large influence on the resulting filament diameter and consequently on the porosity of the scaffolds.
Development of a Water Brake Dynamometer With Regard to the Modular Product Design Methodology
Authors: Torabnia Shams , Banazadeh Afshin
Published: October 2014

This paper summarizes a research project in the field of design and manufacturing of a water brake dynamometer for power testing facilities. In the current study, the design process of a water brake with drilled rotor disks is presented. This process is examined against the development of a water brake for a 4MW gas turbine power measurement at 15,000 RPM speed. The proposed algorithm is based on vital assumptions such as; applying product designing issues and limited modular analysis that urges the disciplinary attitude and leads to the possibility of rapid development, easy maintenance and ease of access. The final scheme is divided into six disciplines with functional classification. These disciplines are rotor, housing, cabs, pedestals, skid and accessories. Accessories, itself, consist of cooling system, lubricating system and control unit. Every discipline has its special function and could be optimized separately. It is possible to change any discipline specification without affecting other disciplines modularity. Using FEM software makes it easy to analyze the mechanical component for static and dynamic load condition regarding complex initial and boundary condition. But it is not wise to analyze whole system for designing a product due to numerical calculation errors. Besides, it is not necessary to use calculation to select machine elements. Rotor dynamics is investigated with modal analysis and related Campbell diagram. Also, transient analysis on housing, rotor and load cell arm is presented. The modal analysis on pedestals and skid is performed to predict the structural behavior under periodic loads caused by rotating unbalance. The process presented in this paper is a method for design of water brake dynamometer. Modularity presented by a product tree and a trend for design cycles associated with computer simulation are the basis of this method. The final product that is designed with this algorithm is successfully manufactured and tested.
Bearing Natural Degradation Detection in a Gearbox: A Comparative Study of the Effectiveness of Adaptive Filter Algorithms and Spectral Kurtosis
Authors: Elasha Faris , Ruiz-Carcel Cristobal , Mba David
Published: October 2014

Bearing faults detection at the earliest stages is vital in avoiding future catastrophic failures. Many traditional techniques have been established and utilized in detecting bearing faults, though, these diagnostic techniques are not always successful when the bearing faults take place in gearboxes where the vibration signal is complex; under such circumstances it may be necessary to separate the bearing signal from the complex signal.

The objective of this paper is to assess the effectiveness of an adaptive filter algorithms compared to a Spectral Kurtosis (SK) algorithm in diagnosing a bearing defects in a gearbox. Two adaptive filters have been used for the purpose of bearing signal separation, these algorithms were Least Mean Square (LMS) and Fast Block LMS (FBLMS) algorithms.

These algorithms were applied to identify a bearing defects in a gearbox employed for an aircraft control system for which endurance tests were performed. The results show that the LMS algorithm is capable of detecting the bearing fault earlier in comparison to the other algorithms.
Transient Free Convection in a Rectangular Water-Filled Enclosure
Authors: Dubovsky Vadim , Kugler Yonatan , Maoz Nimrod , Letan Ruth
Published: October 2014

Transient laminar free convection in a water-filled rectangular enclosure has been studied experimentally and numerically. The study aimed at gaining an insight into the physical phenomena, illustrated by the flow patterns and the temperature stratification, from the initial stage of a homogeneous fluid through the transient evolving process.

The experimental setup consisted of two rectangular water-filled enclosures: the smaller one contained a heat source and was centrally immersed in the larger one. Dye was injected for visualization of the rising boundary layer over the inner container walls, and the accumulation of the colored layers in the upper zone of the outer container. Simultaneously, the temperature measurements, by thermocouples and an infra-red camera, displayed the formation of a stratified structure.

The numerical study was conducted three-dimensionally, using the Fluent 6.3 software. The stratified temperature field, observed experimentally, was well-predicted by the numerical model.

The heat transfer rates and the transient averaged Nusselt numbers were compared with the data in the literature. The current, constant power input yielded Nu/Ra0.25∼0.7 in the range of Fo/Ra0.25 = 0–3.
Diffusion Measurements Using DOE Schardin’s Schlieren #2 Technique
Authors: Ambrosini Dario , De Leo Cinzia , Paoletti Domenica , Galli Giorgio
Published: October 2014

The diffusion process is very important in many engineering applications. However, there is a shortage of data about diffusion, especially between liquid mixtures (such as water and glycerin, water and salt, etc.), which justifies the search for simple and accurate experimental techniques.

Optical techniques are recognized as powerful tools to investigate fluid flow phenomena in transparent media.

The aim of this paper is the development of an optical experimental technique, based on Diffractive Optical Element (DOE) Schardin’s schlieren # 2, for measuring liquid diffusion coefficient. This technique is then coupled to a new data treatment, based on correlation algorithms of the Particle Image Velocimetry (PIV) type, allowing the use of displacements recorded in the entire cell rather than just between two points.

Principles of the method and preliminary experimental results for the diffusion of a 1.75 M (moles/l) aqueous solution of common salt (NaCl) in pure water are given. These results are in good agreement with the literature.
Managing the Conceptualization Process in Innovative Engineering Design, Demonstrated on a Hybrid Two-Wheeler Design Case Study
Authors: Roser Holger M. , Walker Paul D.
Published: October 2014

The process of conceptualizing innovative designs is multifaceted and inherently difficult to perform successfully. It is largely characterized by the designer’s capability to find solutions to design problems beyond existing norms. General agreement suggests this process should entail a holistic approach for conceiving new ideas, which are expanded, assessed, developed, refined, and implemented as part of an iterative problem solving cycle. Suitable design procedures and skills are therefore vital as most of the final cost of a product or system is committed within the early conceptualization stage.

This paper builds on engineering design techniques previously developed by the author, namely the Design Process Framework in conjunction with the Concept Assessment Taxonomy (CAT) at the heart of concept development [1]. The main emphasis of the work presented herein is the application of said framework to a new design challenge in order to further test and demonstrate its practicality in a real world context: the conceptual development of an innovative, modular, hybrid-electric powertrain for two-wheelers.
Reverse Engineering Using Close Range Photogrammetry for Additive Manufactured Reproduction of Egyptian Artefacts and Other Objets d’art
Authors: Kaufman John , Rennie Allan E. W. , Clement Morag
Published: October 2014

Photogrammetry has been in use for over one hundred and fifty years. This research considers how digital image capture using a medium range Nikon Digital SLR camera, can be transformed into 3D virtual spatial images, and together with additive manufacturing (AM) technology, geometric representations of the original artefact can be fabricated. The research has focused on the use of photogrammetry as opposed to laser scanning (LS), investigating the shift from LS use to a Digital Single Lens Reflex (DSLR) camera exclusively.

The basic photogrammetry equipment required is discussed, with the main objective being simplicity of execution for eventual realisation of physical products. As the processing power of computers has increased and become widely available, at affordable prices, software programs have improved, so it is now possible to digitally combine multi-view photographs, taken from 360°, into 3D virtual representational images. This has now led to the possibility of 3D images being created without LS intervention.

Two methods of digital data capture are employed and discussed, in acquiring up to 130 digital data images, taken from different angles using the DSLR camera together with the specific operating conditions in which to photograph the objects. Three case studies are documented, the first, a modern clay sculpture, whilst the other two are 3000 year old Egyptian clay artefacts and the objects were recreated using AM technology. It has been shown that with the use of a standard DSLR camera and computer software, 2D images can be converted into 3D virtual video replicas as well as solid, geometric representation of the originals.
Research on External and Internal Induction Heating Effectiveness of Injection Molds by Means of Thermovision Measurements
Authors: Mrozek Krzysztof , Staniek Roman , Szostak Marek
Published: October 2014

The aim of this work is to compare the effectiveness of two induction heating methods of injection molds by means of thermovision measurement. The problem of selecting external or internal induction heating for thin-walled moldings used in electrical and electronic industry is taken into consideration. At first, the boundary conditions were defined. Then a group of three moldings with different defects were selected. The defects that have been taken to remove by means of induction heating are: weld lines, breaking hinges, air traps and diesel effect. In order to compare the methods of heating two models were created. The first one was made as a block of steel with milled grooves with a width of 2mm and a depth varying from 1 to 12mm. The second model consisted of two parts, one being placed in the second.

The research stand consisted of prepared models, induction generator with power of 10kW, specially shaped inductor, thermovision camera and temperature sensor of PT100 type as a reference. First, the surface with milled grooves was heated in four different sectors (because of the shape of inductor) in time of 2s. The area of low-depth grooves heated up to 154°C while the surface with 12 mm grooves heated up to 120°C. It comes from eddy currents flowing. This phenomenon shows that effectiveness of external heating of grooved surface decreases with increasing of grooves depth.

In the second case the cavity insert was heated as a coil inside the inductor which was located inside the mold. The measured value was the time of heat transfer from heated area to the forming surface in three configurations.
Linear Control Root-Clustering of Uncertain Systems
Authors: Gutman S.
Published: October 2014

In the design of linear control systems, it is desired to assign the closed loop spectrum in sub-regions (as opposed to locations) of the complex plane. The present paper establishes a matrix root-clustering criterion for an important class of regions, and develops a linear feedback control that assigns the closed loop spectrum in the desired region. This is done for both nominal and uncertain systems.
Coupling a Linear Pressure and Mass Flow Frequency Model Obtained From Measurements at the Intake of an IC Engine With a Non-Linear Time Domain Code
Authors: Mezher Haitham , Chalet David , Migaud Jérôme
Published: October 2014

Engine simulation software has become synonymous with automotive design and component development. An integral part of any engine simulation is the correct modeling of the air flow at the intake. This air flow, which is highly compressible and unsteady, has a first order influence on the trapped air mass inside the cylinder and therefore on the behavior of the engine (torque response and emissions). The non-linear modeling of the air paths at the intake is done using a space-time meshing and by solving the 1D equations with a proper time scheme. Such methods are the bases of today’s engine simulation codes [1]. The main constraint with these methods is the time needed to model complex geometries, whether being the simulation time or the time spent on calibrating the said models with experimental measurements. These complicated geometries become problematic to accurately predict, particularly the charge air cooler (CAC) which is responsible for cooling the air flow on a turbocharged engine.

Another approach is to use frequency domain models to describe the fluctuating pressure and mass flow [2]. Although this approach is simpler, faster in terms of computing time and offers many experimental techniques to characterize complicated geometries; important limitations can appear when it is confronted to the effects of high pressure levels and pulsating mass flow. Furthermore, the models behind such methods are designed to be used in the frequency domain, contrary to an engine simulation that works solely with time domain variables.

In this article, a linear frequency domain model known as a transfer matrix is used. This concept is nothing new in acoustics; however here it was developed by experimentally measuring the transfer matrix [3] for a simple tube on a dedicated bench under conditions similar to those encountered on an engine [4]. The approach is then extended to measure the transfer matrix of a charge air cooler (CAC) on a real engine test bench. The measured discrete transfer matrix, defined in terms of fluctuating pressure and mass flow, is then transformed to a continuous frequency model and coded in Simulink®. The latter is coupled to the non-linear engine simulation software GT-Power®.

The objective is to accurately model the pressure and mass flow of a complicated geometry using experimental measurements and a linear frequency model then to couple the transfer matrix to an engine simulation code, thus replacing the need for a meshed model.
Optimization of Machining Surplus Distribution Relative to Hardness of the Machined Surface
Authors: Gessner Andrzej , Staniek Roman , Adam Waldemar
Published: October 2014

Iron cast machining is nowadays preceded by the process of marking out, ascertaining appropriate casting precision and size of machined surface surpluses. The procedure entails delineating (etching) boundaries of the nominal machining surpluses upon the raw cast surfaces. Their size, standardized according to the ISO 8062 certificate, depends on maximal cast dimensions and the casting method applied. The characteristic machining surplus size of the hereby investigated typical industrial casts ranges between 6 and 8 mm. As casting accuracy is determined by individual foundry standards, the actual machining surplus size values commonly differ from the nominal ones. Thus, in order to ascertain appropriate machining of a given cast, variable surplus distribution is warranted, resulting in actual surplus size values of 2–12 mm.

Inherent to the iron casting procedure are variable hardness values within the casting wall cross-section, with the outer wall surface (directly contingent to the mold that rapidly cools the cast) characterized by the highest hardness value, decreasing incrementally towards its center. Verification of surface hardness values takes place after machining and involves selected work surfaces (e.g. base areas of a runner block). Excessive machining of oversized surpluses within the verified areas results in insufficient hardness of their surfaces.

Bearing the above considerations in mind, optimization of surplus distribution was attempted, relating to most advantageous hardness values of selected cast work surfaces. The investigation was conducted under industrial conditions, upon milling center framework casts. The selected work surfaces were processed gradually; the surface hardness was measured after each machining step. Results thus obtained were implemented for further machining surplus optimization of equivalent casts.
Modelling and Testing of a Toroidal CVT
Authors: Riszczuk Daniel , Glovnea Romeo
Published: October 2014

This paper deals with the design and testing of a miniature CVT prototype. The CVT under study is a special toroidal-type, which is able to maintain a quasi-constant power at the output element by automatically changing the transmission ratio function of the torque applied to the output element. The power-transmitting elements of the device have been built by modifying rolling element bearings.