bluuebunny/crossref_metadata_2025 huggingface dataset:
Electromechanical Coupling of PZT Nanofibers
Authors: Xu Shiyou , Shi Yong
Published: August 2009

This paper presented the results of electromechanical characterization of PZT nanofibers through applied mechanical strain and forced vibration. PZT nanofibers were fabricated by electrospinning process. Titanium film with ZrO2 layer was used to collect the nanofibers and also used as the substrates of the test coupons for the bending tests. Mechanical strain was applied to the test coupons through three-point-bending using Dynamic Mechanical Analyzer (DMA). The largest output voltage was 170mV under 0.5% applied strain. Silicon substrate with trenches was also used to collect the PZT nanofibers for the forced vibration tests. The output voltage from 150Hz sinusoid vibration source was also measured. The peaks of the output voltage were 64.9mV and −95.9mV, respectively. These tests have demonstrated the piezoelectric response of PZT nanofibers. Further tests are to be conducted to precisely determine the piezoelectric constants of PZT nanofibers.
Seismic Response Controlled Structure With Semi-Active Mass-Damper
Authors: Yang Fan , Sedaghati Ramin , Esmailzadeh Ebrahim
Published: August 2009

The structural vibration suppression using active and semi-active mass damper is investigated. The controller for full-active controlled mass dampers is designed using the H2/LQG method. Magneto-Rheological (MR) damper is used to design the semi-active controlled mass damper. The inverse MR-damper model is developed on the base of an improved LuGre friction model. It combined with the proposed H2/LQG controller to control the input current of the MR-damper to suppress the structural vibration efficiently. The illustrated examples are presented to compare the vibration suppression effectiveness of semi-active mass damper with MR-damper using the proposed controller with those reported in literatures in order to illustrate the validity of the proposed methodology.
Numerical Study of Film Cooling Enhancement in Gas Turbine Combustor Liner
Authors: Subbuswamy Ganesh , Li Xianchang
Published: August 2009

Combustion chamber or combustor is one of the hottest parts of a gas turbine. Liner is where the actual flame occurs in a combustor and thus, the hottest part of the combustor. The temperature of working fluid inside a liner is about 1200 to 2000K. Because of the hot fluid, the liner is heated up to a temperature almost impossible for the material to withstand. Although the mechanical stresses experienced by the combustor liner are within acceptable limits, high temperatures and large temperature gradients affect the structural integrity of its components, which makes the liner a very critical component of a gas turbine in structural and thermal designs. Film cooling is a traditional method of cooling the inner surface of liner. In film cooling for a combustor, axial holes are drilled along the surface of the liner at discrete locations, through which cold air is injected axially into the liner to provide a film of cool air that prevents direct contact of hot air, and thus, protects the inner wall surface. The film is destroyed in the downstream to the flow because of mixing of cool and hot air. Though this method provides an acceptable cooling, there is a compromise with the increased net benefits of the gas turbine. Therefore, there is a need for new cooling techniques or enhancing the techniques available. The current work is a numerical simulation of film cooling in a model combustor. The effect of coolant injection angles and blowing ratios on film cooling effectiveness is studied. One innovative method, cooling with mist injection, is explored to enhance the performance of film cooling. The effect of droplet size and mist concentration, which can affect the performance of the mist injection, is also analyzed. Fluent, a commercial CFD software, is used in the current work for numerical simulations.
Stability Analysis of a Flexible Two-Link Timoshenko Manipulator Using Boundary Control Method
Authors: Rastgoftar Hossein , Mahmoodi Masih , Eghtesad Mohammad , Kazemi Mojtaba
Published: August 2009

In this article, the stabilization problem of two flexible one-link and two-link manipulators is solved using boundary control method. To account for the flexibility of links, Timoshenko beam theory is adopted and using Lyapunov stability theorem, forces and torques necessary to be applied at the joints of the manipulators are calculated. Finally the problem of trajectory tracking for this robot is briefly discussed.
Nonlinear Dynamics of the Chua’s Circuit System Revisited
Authors: Luo Albert C. J. , Xue Bing
Published: August 2009

In this paper, periodic and chaotic behaviors in the Chua’s circuit system are discussed. The solutions of the system in different regions with different parameters are obtained. The switching boundaries are introduced for systems switching because of different system parameters. In the vicinity of the switching boundary, the normal vector-field product is introduced to measure the flow switching on the separation boundary, and the grazing and passable conditions to the discontinuous boundary are presented. The basic mappings are defined and periodic responses of such a system are predicted analytically from the mapping structures. The local stability and bifurcation analysis are carried out.
Enhancement of Hard Disk Drive Heat Dissipations With Integrated Cooling Devices
Authors: Yang J. P. , Tan C. P. H. , Ong E. H.
Published: August 2009

Thermal management has become a significant issue to be considered whilst designing high performance and high reliable hard disk drives (HDD). This paper proposes a compact ultra-thin cooling device for enhancing heat dissipation of HDD. The miniature device was designed and prototyped to its optimal cooling efficiency according to the thermal characteristics of operating HDD. The experimental results of this newly developed device show that it can offer up to 35% enhancement of heat dissipation with a lower power consumption of 10 mW. Furthermore, the low power consumption device has been fully integrated with the disk drive without modifying the structure of the disk drive. This device provides a key for the design engineers in developing reliable and longer operational life hard disk drives.
Study of Heat Transfer of Gas Flow Heated by Nano-Probe via Direct Stimulation Monte Carlo (DSMC)
Authors: Liu X. J. , Yang J. P. , Yang Y. W.
Published: August 2009

Applications of heated tip/surface configuration for micro-/nano-electromechanical systems (MEMS/NEMS) have been widely explored in these years. Since the small gaps in these MEMS/NEMS are comparable to the mean free path of gaseous molecules, the heat transfer via gaseous molecules from the heated tip to the substrate is fundamentally different from macroscopic conduction or convection heat transfer in gases. In this paper, the heat transfer of the rarefied gases heated by hot nano-tip is investigated by means of the Direct Simulation Monte Carlo (DSMC) method. The results show that both tip geometry and tip-substrate distance affect the heat flux density distribution. With the increase of the crossing-angle θ of the nano-tip, the heat flux tends to decrease, while the spatial resolution tends to improve. Moreover, the heat flux density and spatial resolution tend to decrease with the increase of distance between the nano-tip and the substrate. Simulation results provide valuable information for the rational design and optimization of the heated nano-probe for topography applications such as thermally assisted data storage.
Integrated Conceptual Design Environment for Centrifugal Compressors Flow Path Design
Authors: Moroz Leonid , Govoruschenko Yuri , Pagur Petr , Romanenko Leonid
Published: August 2009

A new method for centrifugal and mixed-type compressors flow paths design based on a unique integrated conceptual design environment is presented in this article. At the heart of this new method is the translation of proven, integrated design environments that have been successfully used for axial turbomachinery for many years. This integrated environment is a seamless and swift processing scheme that incorporates stages aerodynamic analysis and preliminary design/sizing based on the one-dimensional method interactive spatial blade profiling, export of blade geometry to CAD and CFD tools, 3D stress and vibration analysis, and finally, flow modeling. The design process is demonstrated for a centrifugal compressor design utilizing AxSTREAM software.
Investigation of Vegetable Oil as Thermal Fluid in Parabolic Solar Collector
Authors: Khan M. M. , Islam M. R.
Published: August 2009

Because of limited sources of fossil fuel, renewable sources of energy are now getting concentration to meet up the huge demand of energy of modern technology. Among the renewable sources, solar energy source is considered to be the most important source because of its unlimited supply and numerous ecologically benign features. However, due to its diluted nature, it is required to concentrate this energy for fruitful utilization. Parabolic solar trough is one of the solar concentrators, for which a thermal fluid is used to absorb the solar radiation. However, most of the thermal fluids that are commonly used are synthetic and toxic in nature. In the frame of the sustainable development principles, it is necessary to establish a set of safe and non-toxic thermal oil for using in a solar collector. In this paper, both clean Canola oil and waste vegetable oil have been used as thermal oil to find out their performance. Experimental studies show a solar absorption efficiency of 77.8% and 37.67% with clean Canola oil and waste vegetable oil, respectively, can be achieved even at low solar irradiation conditions. All design criteria are investigated and reported in this paper.
Active Separation Control of Flow Over a Wall-Mounted Hump Using Zero-Efflux Synthetic Jet
Authors: Gan Subhadeep , Ghia Urmila , Ghia Karman
Published: August 2009

Most practical flows in engineering applications are turbulent, and exhibit separation which is generally undesirable because of its adverse effects on performance and efficiency. Therefore, control of turbulent separated flows has been a topic of significant interest as it can reduce separation losses. Often, flow control work employs passive techniques to manipulate the flow. These approaches do not require any additional energy source to achieve the control, but are accompanied by additional viscous losses. However, it is more desirable to employ active techniques as these can be turned on and off, depending on the flow control requirement. Use of synthetic jets has gained popularity in recent times for active flow control because of their ability to transfer linear momentum to the flow system without net-mass injection across the boundary in the vicinity of separation. The present work is Case 3 of the 2004 CFD Validation on Synthetic Jets and Turbulent Separation Control Workshop, http://cfdval2004.larc.nasa.gov/case3.html, conducted by NASA for the flow over a wall-mounted hump. This flow is characterized by a simple geometry, but, nevertheless, is rich in many complex flow phenomena such as shear layer instability, separation, reattachment, and vortex interactions. The baseline case and control case with steady suction has been successfully simulated by Gan et al., (2007 and 2008). The present work is focused on implementing a synthetic jet to achieve flow control. The jet was simulated by implementing an analytical sinusoidal velocity boundary condition at the surface of the jet exit. The jet-exit velocity has a parabolic profile across the control slot, and a sinusoidal temporal variation. The flow is simulated at a Reynolds number of 371,600, based on the hump chord length, C, and a Mach number of 0.04. The synthetic control jet exits through a slot located at approximately 0.65 C. Solutions are obtained using the three-dimensional RANS SST turbulence model, and the DES and LES turbulence modeling approaches. Multiple turbulence modeling approaches help to ascertain what techniques are most appropriate for capturing the physics of this complex separated flow. The location of the reattachment behind the hump is compared with experimental results. The successful control of this turbulent separated flow leads to a reduction in the reattachment length, compared with the baseline case. Velocity contours at several streamwise locations are presented and compared to experimental results. Mean flow parameters such as pressure coefficients and skin-friction coefficient are presented. The paper includes detailed comparisons of turbulent parameters such as the Turbulent Kinetic Energy (TKE) and Reynolds stress profiles, with experimental results. Instantaneous vorticity contours are presented from the simulations. Discussion are presented of the effects of synthetic jet control on flow separation and reattachment and the resulting enhancement of performance and efficiency.
Conjugate Heat Transfer and Film Cooling of a Multi-Stage Cooling Scheme
Authors: Ghorab M. , Kim S. I. , Hassan I.
Published: August 2009

Cooling techniques play a key role in improving efficiency and power output of modern gas turbines. The conjugate technique of film and impingement cooling schemes is considered in this study. The Multi-Stage Cooling Scheme (MSCS) involves coolant passing from inside to outside turbine blade through two stages. The first stage; the coolant passes through first hole to internal gap where the impinging jet cools the external layer of the blade. Finally, the coolant passes through the internal gap to the second hole which has specific designed geometry for external film cooling. The effect of design parameters, such as, offset distance between two-stage holes, gap height, and inclination angle of the first hole, on upstream conjugate heat transfer rate and downstream film cooling effectiveness performance are investigated computationally. An Inconel 617 alloy with variable properties is selected for the solid material. The conjugate heat transfer and film cooling characteristics of MSCS are analyzed across blowing ratios of Br = 1 and 2 for density ratio, 2. This study presents upstream wall temperature distributions due to conjugate heat transfer for different gap design parameters. The maximum film cooling effectiveness with upstream conjugate heat transfer is less than adiabatic film cooling effectiveness by 24–34%. However, the full coverage of cooling effectiveness in spanwise direction can be obtained using internal cooling with conjugate heat transfer, whereas adiabatic film cooling effectiveness has narrow distribution.
Thermal Management Using Composite Structures
Authors: Alam M. Khairul , Sepulveda Juan L. , Loutfy Raouf O.
Published: August 2009

The continuing increase in integrated circuits (IC) power levels and microelectronics packaging densities has resulted in a need of materials with higher thermal conductivities and new thermal management solution designs. A base plate design that uses integrated metalized dielectric including Aluminum nitride or polycrystalline diamond (PCD) joined to a diamond/Al composite heat spreader with fins or foam attached by a single step casting is proposed. A numerical study of the design parameters is presented and analyzed. The new material and integrated bonding design can be further improved by changing the materials to a diamond/Copper base plate with polycrystalline diamond dielectric and graphitic foams for convective transport.
Development of an Online Virtual Reality-Based Advanced Manufacturing Curriculum for Use in Professional Certification
Authors: El-Mounayri Hazim A. , Fernandez Eugenia , Wasfy Tamer
Published: August 2009

An innovative online module in advanced manufacturing is developed based on a state-of-the-art virtual reality learning tool. The Advanced Virtual Manufacturing Laboratory (AVML) is a collaborative web-based virtual learning environment for integrated lecture and lab delivery which focuses on advanced machining using Computer Numerically Controlled (CNC) machine tools. The system seamlessly and synergistically integrates multimedia lecture, interactive 3D simulation, and realistic experimentation in a virtual reality environment. The development involves three main elements: a simulator for CNC milling and lathe machines, a virtual-environment display engine, and an intelligent-agent engine. The virtual reality environment provides training in different modes on different operating procedures with the help of an intelligent virtual tutor. The AMVL content was designed to lead to certification. With the help of a NIMS certified practitioner the curriculum is refined to ensure a successful pathway to certification. Support for this pathway to certification is provided by the results of a quasi-experimental randomized study to assess the learning effectiveness of the curriculum content of the AVML. The development of the AVML, its pathway to certification, and the results of the learning effectiveness of the online virtual reality environment are presented in this paper.
Interfacial Thermal Resistance in Nanoscale Heat Transfer
Authors: Balasubramanian Ganesh , Banerjee Soumik , Puri Ishwar K.
Published: August 2009

We investigate nanoscale thermal transport across a solid-fluid interface using molecular dynamics simulations. Cooler fluid argon (Ar) is placed between two heated iron (Fe) walls, thereby imposing a temperature gradient within the system. Fluid-fluid and solid-fluid interactions are modeled with Lennard-Jones potential parameters, while Embedded Atom Method (EAM) is used to describe the interactions between solid molecules. The Fe-Ar interaction causes ordering of fluid molecules into quasi-crystalline layers near the walls. This causes temperature discontinuity between these solid-like Ar molecules and the adjacent fluid. The time evolution of the interfacial (Kapitza) thermal resistance (Rk) and Kapitza length (Lk) are observed. The averaged Kapitza resistance (Rk,av) varies with the initial temperature difference between the wall and the fluid (ΔTw) as Rk,av∝ΔTw−0.82.
Analytical Estimation of Power Harvested From a Rotating Helicopter Blade
Authors: Warner Grant M. , Ogunlade Olufemi , Lin Ray Sing , Chaudhry Zaffir , Wake Brian
Published: August 2009

Embedded wireless sensor networks are part of a strategy for implementing improved structural health and usage monitoring in rotorcraft. In order to realize this goal, methods of powering the embedded sensors have to be identified. One approach is to make the power supply become an integral part of the sensor. This integrated monitoring system will then be less intrusive and, therefore, easier to integrate into existing systems. Piezoelectric materials can be an important part of this strategy. One method to harness power is to use piezoelectric materials to recover energy lost due to vibration and rotation of the equipment. This recovered energy can then be used to provide energy to power sensors directly or to extend the lifespan of batteries which power the sensors. This paper investigates the potential of using strains on a rotating blade to power sensors during flight. The preliminary numerical investigation indicates that this may be a promising approach.
CANTIA Code for the Probabilistic Assessment of Inspection Strategies for Steam Generator Tubes
Authors: Revankar Shripad T. , Wolf Brian , Riznic Jovica R.
Published: August 2009

The Canadian Nuclear Safety Commission (CNSC) recently developed the CANTIA methodology for probabilistic assessment of inspection strategies for steam generator tubes. Assessment of the conditional probabilities of tube failures, leak rates, and ultimately risk of exceeding licensing dose limits as an approach used to steam generator tube fitness-for-service assessment has been increasingly used in recent years throughout the nuclear power industry. The ANL/CANTIA code predictions were systematically studied to evaluate the code capability to predict the leak rates through the flawed steam generator tubes. In this evaluation the code models on the crack opening area, the probabilistic models and the critical flow rate models were studied and their applicability to available experimental data base was examined.
Reformulating the Statics Course: A Design-Based Approach
Authors: Condoor Sridhar S.
Published: August 2009

Statics is a pivotal course, whose concepts serve as the building blocks for future courses in engineering. From the experience of teaching the follow-on courses to statics, we found several systemic problems present in most statics textbooks. These problems manifest themselves as lower-than-expected abilities in the students when applying the concepts to design/analyze real systems in subsequent courses. The resulting disappointment in engineering educators is common and well documented. The pedagogy outlined in this paper is based on the premise that students learn more effectively when the relevance of the concepts to real world problems and a systematic improvement in their skill set is tactilely, emotionally, and rationally understood. To this end, the pedagogy brings design theory into the course content. The paper discusses rationale behind the pedagogy and its possible implementation scheme with examples. The pedagogy is flexible and can be integrated into an existing learning approach.
Heat Transfer Spectroscopy and “Heat Transfer-Distance” Curves
Authors: Narayanaswamy Arvind , Shen Sheng , Chen Gang
Published: August 2009

Thermal radiative transfer between objects as well as near-field forces such as van der Waals or Casimir forces have their origins in the fluctuations of the electrodynamic field. Near-field radiative transfer between two objects can be enhanced by a few order of magnitude compared to the far-field radiative transfer that can be described by Planck’s theory of blackbody radiation and Kirchoff’s laws. Despite this common origin, experimental techniques of measuring near-field forces (using the surface force apparatus and the atomic force microscope) are more sophisticated than techniques of measuring near-field radiative transfer. In this work, we present an ultra-sensitive experimental technique of measuring near-field using a bi-material atomic force microscope cantilever as the thermal sensor. Just as measurements of near-field forces results in a “force distance curve”, measurement of near-field radiative transfer results in a “heat transfer-distance” curve. Results from the measurement of near-field radiative transfer will be presented.
Biodiesel Combustion and Emissions in Engines Using Modern Common-Rail Fuel Injection Systems
Authors: Karra Prashanth K. , Veltman Matthias K. , Kong Song-Charng
Published: August 2009

This study performed experimental testing of a multi-cylinder diesel engine using different blends of biodiesel and diesel fuel. The engine used an electronically-controlled common-rail fuel injection system to achieve a high injection pressure. The operating parameters that were investigated included the injection pressure, injection timing, and exhaust gas recirculation rate. Results showed that biodiesel generally reduced soot emissions and increased NOx emissions. The increase in NOx emissions was not due to the injection timing shift when biodiesel was used because the present fuel injection system was able to give the same fuel injection timing. At high exhaust gas recirculation rates, emissions using regular diesel and 20% biodiesel blends are very similar while 100% biodiesel produces relatively different emission levels. Therefore, the increase in NOx emissions may not be a concern when 20% biodiesel blends are used with high exhaust gas recirculation rates in order to achieve low temperature combustion conditions.
Design Experience Using Software Tools in Undergraduate Engineering Mechanics Courses
Authors: Nagchaudhuri Abhijit , Yilmaz Emin
Published: August 2009

Statics, Dynamics, and Mechanics of Materials form the basic sequence of engineering mechanics courses in engineering curricula. Traditionally, these courses have been designated as “engineering science” courses with significantly more emphasis in analysis to reinforce engineering fundamentals, and little to no importance to “engineering design”. With the outcome based approach to undergraduate engineering education adopted by Accreditation Board of Engineering and Technology and the framework laid out by Engineering Criteria (EC 2000) significant reform efforts are underway to incorporate design experience throughout the engineering curricula. Most engineering programs across the nation have developed and implemented a freshman design course to introduce engineering design at the beginning of the college experience for engineering majors. To sustain the momentum, it therefore follows that subsequent courses should sustain the design emphasis in the freshman and sophomore years. Design, however, is a time consuming complex iterative process somewhat different from the convergent nature of engineering science. Modern software tools provide a time efficient and pedagogically effective way of integrating engineering design project with the engineering mechanics sequence without compromising the engineering science fundamentals. In this paper design projects that have been integrated in Statics, Dynamics, and Mechanics of Material courses offered by the author using software tools such as Working Model, MD-Solids, Pro-Engineer, Solid-works etc. supplemented by computational tools such as MATLAB and EXCEL are outlined. Discussion based on student feedback and relevance to ABET outcomes is also forwarded.
Computational Modeling of Planar SOFC: Effects of Volatile Species/Oxidant Mass Flow Rate and Electrochemical Reaction Rate on Convective Heat Transfer
Authors: Venkata P. P. , Jog M. A. , Manglik R. M.
Published: August 2009

A three-dimensional computational simulation of an intermediate temperature planar, tri-layered solid oxide fuel cell is considered for steady incompressible fully developed laminar flow in the interconnect ducts of rectangular cross section, with uniform supply of volatile species (80% H2 + 20% H2O vapor) and oxidant (20% O2 + 80% N2) at the electrolyte surface. The governing equations of mass, momentum and energy conservation coupled with that for electrochemical species are solved computationally. The Darcy-Forchheimer model described the fuel and oxidant transport through the porous electrodes, where the flow is in thermal equilibrium with the electrolyte matrix. The anode-side triple phase boundary is computationally resolved to capture the electrochemical reaction that results in current and volumetric heat generation. Parametric effects of the interconnect design (contact area and channel size) on the variation of thermal-hydrodynamic and electrical performances of the cell are presented. These highlight the effect of the flow rate on the Nernst potential and, in turn, the variations in current density, temperature and mass/species distributions, flow friction factor, and convective heat transfer coefficient. Interconnect channels of different cross-section aspect ratio (width/depth ∼ 0.5–2.0) with electrode-interface-contract half widths for minimum and unchanged area specific resistance) are contrasted so as to evaluate the optimal overall electrical and convective cooling performance of the planar anode-supported SOFC.
Advanced Simulation/Modeling and Reliability of Fine Pitch (130um) Lead-Free Flip-Chip Package
Authors: Banijamali Bahareh , Mohammed Ilyas
Published: August 2009

Flip-chip technology has been introduced in recent years which accommodate the ever increasing demands for higher performance and I/O density, while achieving smaller form factor and offering a cost effective solution. As the industry moves toward the 65nm and 45nm technology node, die sizes require a significant reduction while accommodating the need for tighter and finer pitches. For decades, the C4 process has served as the main interconnect method in the flip-chip package. But with bump pitches shrinking, the solder bump based C4 process is facing challenges in terms of reducing pitch and underfill process. At the same time, increasing challenges for flip-chip are seen by the movement toward lead-free solder bumps and low-k dielectric layers. This work conducted simulations and analyses on Tessera developmental μPILR flip chip package incorporating a 130um pitch bump array, using 3-D finite element method (FEM). This study explores the effect of various design parameters on package reliability while providing suggestions for selecting packaging materials. Based on modeling data certain set of over mold, underfill and thermal interface materials enhance overall package reliability performance. Solder fatigue life prediction was performed and solder bump reliability was compared for Tessera flip chip technology and standard flip chip solder joints using Modified Anand solder material properties and Darveaux fatigue life prediction theory. Further more, fracture mechanics approach was applied, and energy release rates were obtained in order to check reliability of low-k dielectric layer, provided passive/low-k material selection. The data presented here provides a baseline for reliability/feasibility of Tessera developmental μPILR flip chip package design for 130um bump pitch. Experimental reliability data is not complete at this time but will be available and published soon.
Impact of Nanoscale Features of Metallic Slits on Mid-Infrared Radiative Properties
Authors: Chen Y.-B. , Chen J.-S. , Fu K. , Hsu P.-F.
Published: August 2009

Mid-Infrared radiative properties (absorptance, reflectance, and transmittance) of submicron gold slit arrays have been numerically studied with rigorous coupled-wave analysis and the finite difference time domain method. The slit width varies from 50 nm to 300 nm and a square feature may attach at either or both slit sides. Although the wavelength is one or two orders of magnitude longer than the side length of features, the attached nanoscale features can modify radiative properties significantly. Directional dependence on radiative properties has also been detail investigated by looking into electromagnetic fields and Poynting vectors of selected slit geometry. One possible physical mechanism, cavity resonance, account for unique radiative properties have been suggested and verified in the study as well.
Casting Core Using Synthetic Resin Coated Sand: Mechanical Properties and Physical Characteristics
Authors: Abdullah Bulan , Jaafar Roseleena , Jaffar Ahmed , Abas Sunhaji Kiyai
Published: August 2009

This paper outlines the study on synthetic resin coated sand which is one of the main moulding materials for manufacturing of moulds and cores in the casting process. The physical characteristics of the synthetic resin coated sand were analyzed for microstructure observation, Grain Fineness Number (GFN), Loss on Ignition (LOI) and X-ray Diffraction (XRD). Two sets of sample were cured at temperatures 200°C and 250°C with a curing time variation of 30, 45, 60, 75 and 90 minutes each. All samples will be tested for mechanical testing: transverse strength, impact (Charpy and Izod) and tensile tests. The results of the study showed that the mechanical properties were greatly influenced by the curing temperature and time. Whereas, the physical characteristics such as the sand grain shape, size and distribution as well as the major constituents of the synthetic resin coated sand were discovered. The data gathered proved to be beneficial for the casting production of cores.
The Determination of Meshing Force Distribution for Spur Gears
Authors: Durali Mohammad , Saryazdi Maryam Gh.
Published: August 2009

This article presents a method for determination of meshing force distribution on contact region of spur gear teeth. In this method it is assumed that there are inter-connected springs on the teeth profile. These springs treat as capacitive fields. The compliance matrices of these fields are determined from the results of finite element analysis done on 3-D model of a gear. The tooth compliance matrix is used as a reference data to determine the tooth deformations for any meshing situation. The meshing force distribution is calculated using this reference data and Hertz theory for contacting bodies. The results of this analysis help in stress analysis under real operation conditions and more reliable design of gears without needing 3-D contact model. So by this method the volume of the calculations is reduced remarkably. The method is applied to a spur gear pair, and the meshing force distribution and meshing stiffness is determined for two cases of ideal and misaligned contacts.
Design Methodology for Hot Mix Asphalt Underlayment With Crossing Diamonds
Authors: Chrismer Steven M. , Davis David D. , Smith Lamont
Published: August 2009

Hot Mix Asphalt (HMA) pavements can be used to improve the performance of crossing diamonds and other high dynamic load track segments. HMA underlayments are one method of strengthening track foundations to improve track superstructure performance. Railroads are looking for standardized designs for HMA similar to what is available for ballast section, crossties and rail. Therefore the authors have developed a rational design method and recommended designs for Hot Mix Asphalt (HMA) underlayments at crossing diamonds. A parametric analysis of typical subgrade conditions and mainline railroad loadings was conducted. These results have been compiled into an easy to use table of minimum HMA thickness vs. subgrade strength.
Improved Tank Car Design Development: Ongoing Studies on Sandwich Structures
Authors: Jeong David Y. , Tyrell David C. , Carolan Michael E. , Perlman A. Benjamin
Published: August 2009

The Government and industry have a common interest in improving the safety performance of railroad tank cars carrying hazardous materials. Research is ongoing to develop strategies to maintain the structural integrity of railroad tank cars carrying hazardous materials (hazmat) during collisions. This paper describes engineering studies on improved tank car concepts. The process used to formulate these concepts is based on a traditional mechanical engineering design approach. This approach includes initially defining the desired performance, developing strategies that are effective in meeting this performance, and developing the tactics for implementing the strategies. The tactics are embodied in the concept. The tactics and concept evolve through engineering design studies, until a design satisfying all of the design requirements is developed. Design requirements include service, manufacturing, maintenance, repair, and inspection requirements, as well as crashworthiness performance requirements. One of the concepts under development encases the pressurized commodity-carrying tank in a separate carbody. Moreover, this improved tank car concept treats the pressurized commodity-carrying tank as a protected entity. Welded steel sandwich structures are examined as a means to offer protection of the commodity tank against penetrations from impacting objects in the event of a collision. Sandwich structures can provide greater strength than solid plates of equal weight. Protection of the tank is realized through blunting of the impacting object and absorption of the collision energy. Blunting distributes impact loads over a larger area of the tank. Energy absorption reduces the demands on the commodity tank in the event of an impact. In addition, the exterior carbody structure made from sandwich panels is designed to take all of the in-service loads, removing the commodity tank from the load path during normal operations. Design studies described in this paper focus on the protection aspect of using sandwich structures. Studies are conducted to investigate the influence of different parameters, such as sandwich height and core geometry, on the force-deformation behavior of sandwich structures. Calculations are carried out numerically using nonlinear finite element analysis. These analyses are used to examine the crashworthiness performance of the conceptual design under generalized impact scenarios.
Research to Understand the Effects of Wheel Impact Loads on Wheel Stress Levels
Authors: Lonsdale Cameron , Rusin Thomas , Hay Thomas
Published: August 2009

In recent years wheel impact loads have become a very important topic in the railroad industry due to operational and safety concerns. Much attention has been given to the level of condemnable wheel impact load as determined by wayside detection systems, and to the root causes of tread defects that lead to these wheel impacts. This paper describes physical testing of a wheelset in an instrumented drop hammer system to examine the effects of impact loading on resultant stress levels at various locations on a wheel’s surface. The drop hammer, typically used for evaluation of draft gears, is located at ASF-Keystone in Camp Hill, PA, and can impart dynamic loads up to a maximum of 2,000 kips, which is well in excess of typical wheel impact loads recorded by wayside impact detection systems. Impact loads for drop hammer wheel testing were generally confined to a maximum of approximately 200 kips. Finite element analysis (FEA) modeling using only mechanical tread loading was conducted to determine the high stress locations for the wheel design and to correlate strain gauge results for static loading on the wheel. The instrumented drop hammer used for wheel impact testing is described, and wheel strain gauge issues are discussed. Vertical split rim wheel failures are described and are briefly reviewed. The implications of impact loading for vertical split rim wheel failures are discussed and recommendations for future work are offered.
Evolutions in Railway Signaling: A “New Age” of Control?
Authors: Fraser Cameron
Published: August 2009

The development of railroad signaling systems evolved with the need to provide interlocking between points and signals, and block working to keep trains a safe distance apart. Accordingly, the archetypal behavior of train control is summed up as providing (1) safe and efficient train movement by (2) the management of train routing and separation. This has been rudimentary since the advent of railway signaling and propagated in even the most contemporary of technologies today.
AC Electrified Rail Train Converter Switching Overvoltage Transients Study
Authors: Ku Bih-Yuan , Hsu Yuan Tai
Published: August 2009

In this paper we present the result of a case study on the switching overvoltage transients of ac electrified railroad trains equipped with switch-type rectifiers in Taiwan Railway Administration (TRA). It was found that new generation of switch-type converters could result in significant over-voltage of magnitude comparable to lightning surge if no proper snubber circuit be used. The switching surge could damage power equipment of nearby trains in the same service zone, as observed in the TRA system. It is recommended that maximum tolerance of switching over-voltage be clearly specified in the procurement phase of new trains with switch-type converters then accurately verified in the commissioning phase to ensure proper preventive measure be installed.
RF Coupling Simulation Model Development for Optimal Placement of Antennas Supporting Wireless Communications Systems
Authors: Gray Robert , DiBenedetto Mike
Published: August 2009

The locomotive cab’s limited rooftop area requires that the transmitting and receiving antennas for communications be placed in close proximity to one another. Currently, no means exist to aid the railroad radio frequency (RF) engineer in placing these antennas so that mutual communications interference is minimized. The goal of this paper is to describe a method that can be used to determine optimal antenna placement in a time- and cost-effective manner. The method described below utilizes various forms of the Friis transmission equation in Monte Carlo simulations.
Unsafe Hunting of Freight Rail Cars
Authors: Huang Wei , Liu Yan
Published: August 2009

Hunting of rail vehicles refers to self-excited oscillation of truck and carbody. This dynamic instability is due to the conicity of the wheels, the wheel/rail creep forces and the action of the suspensions. Hunting increases wheel/rail wear, causes damage to sensitive lading and in extreme cases can throw the track out of geometry. Furthermore, severe hunting can create unsafe operating conditions that lead to derailments. Although it is widely recognized that truck hunting is not a good thing, it is a fact that many thousands of trucks do hunt on any given day but the number of derailments from hunting are few. So when is the hunting unsafe? Database and parametric studies of unsafe hunting are presented in this paper. The FRA database was used to study the hunting derailments by year, car type, track, speed, load condition, weather and temperature. Parametric studies of hunting and unsafe hunting of three-piece freight cars were conducted based on a large number of measured wheel profiles in combination with worn and new rail profiles. The vehicle, track and operational factors that have the major influence on unsafe hunting are analyzed and the conditions of unsafe hunting presented.
A Nonlinear Rail Vehicle Dynamics Computer Program SAMS/Rail: Part 2—Preliminary Validation of BETA Release
Authors: Marquis Brian , Curtis Erik , Zaazaa Khaled E. , Whitten Brian , El-Sibaie Magdy , Tajaddini Ali
Published: August 2009

The Federal Railroad Administration is sponsoring a research project at the University of Illinois at Chicago (UIC) to develop state of the art modeling and simulation capabilities for railroad vehicle systems. This involves the development of a general purpose code for the dynamic simulation and performance evaluation of railroad vehicle systems. During development of the beta version, SAMS/Rail (Systematic Analysis of Multibody Systems/Rail), a number of simplified models have been constructed to validate the program. These examples include single wheelset models, truck models, full vehicle models and industry recognized benchmarks. In each of these cases, comparisons have been made to available solutions. These results are described in this paper.
A Nonlinear Rail Vehicle Dynamics Computer Program SAMS/Rail: Part 1—Theory and Formulations
Authors: Zaazaa Khaled E. , Whitten Brian , Marquis Brian , Curtis Erik , El-Sibaie Magdy , Tajaddini Ali , Shabana Ahmed A.
Published: August 2009

Accurate prediction of railroad vehicle performance requires detailed formulations of wheel-rail contact models. In the past, most dynamic simulation tools used an offline wheel-rail contact element based on look-up tables that are used by the main simulation solver. Nowadays, the use of an online nonlinear three-dimensional wheel-rail contact element is necessary in order to accurately predict the dynamic performance of high speed trains. Recently, the Federal Railroad Administration, Office of Research and Development has sponsored a project to develop a general multibody simulation code that uses an online nonlinear three-dimensional wheel-rail contact element to predict the contact forces between wheel and rail. In this paper, several nonlinear wheel-rail contact formulations are presented, each using the online three-dimensional approach. The methods presented are divided into two contact approaches. In the first Constraint Approach, the wheel is assumed to remain in contact with the rail. In this approach, the normal contact forces are determined by using the technique of Lagrange multipliers. In the second Elastic Approach, wheel/rail separation and penetration are allowed, and the normal contact forces are determined by using Hertz’s Theory. The advantages and disadvantages of each method are presented in this paper. In addition, this paper discusses future developments and improvements for the multibody system code. Some of these improvements are currently being implemented by the University of Illinois at Chicago (UIC). In the accompanying “Part 2” and “Part 3” to this paper, numerical examples are presented in order to demonstrate the results obtained from this research.
Advance Warning Devices for Rail Transit Personnel for: Approaching Trains; Fire, Chemical Biological Releases; Emergency Responders
Authors: Bartek Peter M.
Published: August 2009

The purpose of this IEEE and Transit IDEA project was to develop and test a device to give rail transit personnel and train operators advance warning of dangers well in advance of entering the danger zones such as approaching train and other potential dangers such as Fire, Chemical, and Biological Releases. This device can provide a reliable way of giving the track worker; train operator and emergency responders a warning in enough time to avoid potential accidents, injuries, or death. Further this device cuts down on incident response time from the Operational Control Center to Command Center to provide additional security and eliminate lost response time. The information provided in this report will enable other rail rapid transit agencies the ability to consider using such devices to give early warning of approaching trains and other dangers to track workers, track walkers, track inspectors, emergency responders and signal personnel and also to give the train operator early warning of the presence of personnel in the track area as well as other dangers ahead.
Predicted Wheel Wear and RCF Performance Using VAMPIRE Automation Routines
Authors: Rogers Philip J. , Dick Matthew G.
Published: August 2009

Predicted wheel performance is an invaluable tool in developing new components such as wheel profiles and truck components and also in understanding and controlling wheel and rail wear and rolling contact fatigue (RCF). This paper outlines a vehicle dynamics trial using VAMPIRE Pro to compare the predicted wear and RCF performance of the WRISA2 wheel profile developed by the National Research Council of Canada (NRC) and the United Kingdom P8 wheel profile using measured wheel profiles from an in-service trial. WRISA2 and P8 profiles were fitted to two passenger trains running in normal service. Wheel profiles were measured every 10,000 miles. These measured profiles were used to predict wear and RCF damage for each wheel of the investigated rail vehicle, using a combination of VAMPIRE transient analysis and another program called the “Whole Life Rail Model” (WLRM). This process was repeated up to 190,000 miles run in service, allowing a clear comparison of the changing rail wear and RCF performance of the two profiles up to this mileage. This process was automated using new features within VAMPIRE that allow communication to 3rd party computer programs including the WLRM, Microsoft Excel, and Microsoft Visual Basic. This research process presents itself to be a very useful tool in predicting wheel wear performance for any number of new wheel and truck components.