Mech 461 Research Projects - Winter 2011
Updated 25-Jan-2011
IMPORTANT INFORMATION FOR STUDENTS
- Project listing is now closed.
- Once you have identified a project you are interested in please arrange to meet with the project supervisor(s) to discuss.
- When the supervisor(s) agrees to accept a student, that student's name will be added in the column below beside the project.
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Research Project List
Measuring Residual Strains in Deformed Metals Using a Focused Ion Beam
SUPERVISORS
B.J. Diak and M.R. Daymond
INTRODUCTION
Residual stresses develop in many materials due to non-uniform thermal changes or plastic deformation in elastically anisotropic materials. The stresses develop over different length scales in the material: from the sample scale down to the grain interior of polycrystals. Hole drilling is one of the most widely used destructive techniques for sample-scale residual stress measurements, due to its precision and low cost. The size and distribution of the holes can give information about the strain gradients in the material.
SCIENTIFIC BACKGROUND
The presented technique takes advantage of the combined milling-imaging features of the focused ion beam (FIB) instrument to scale down the widely known hole drilling method. This method consists of drilling a sub-micrometer diameter hole in a solid with inherent residual stresses and measuring the strains/displacements caused by the local stress release, that takes place around the hole. The focused ion beam instrument rapidly accelerates a focused beam of Ga+ ions toward a grounded sample: the interaction results in both ballistic milling of the material and imaging signals from secondary ions and electrons. The optimum resolution of the Queen’s instrument is 5nm, which theoretically would allow many holes to be made across a single grain in a polycrystal to assess the strain gradients present.
RESEARCH OBJECTIVE
The objective of this work is to: (1) assess the ability of the FIB to drill uniform sub-micrometer diameter holes in surface grains of annealed and deformed metals; and (2) relate the shape change of these holes during milling to the residual strain in the material.
EXPERIENCED ENABLED
The student will become familiar with plasticity of metals, focused ion beam milling, and orientation imaging microscopy.
BACKGROUND REQUIRED
MECH 371, interest in mechanical properties of materials and good hands-on capabilities.
Gamma and Neutron Tomography of Concrete Samples and Underwater Concretions from Shipwrecks
SUPERVISORS
M.R. Daymond, with G. Bevan (Classics), Paul Hungler (RMC) and J. Schreiner (Physics/KGH)
INTRODUCTION
Research tools that provide 3D images of features in a wide range of materials are vital for conducting state-of-the-art research. Tomographic imaging works by taking multiple 2D transmission images (“portal images”) of an object; each image is analogous to a medical x-ray but obtained with a much higher spatial resolution and higher energies. The object is rotated a small amount (usually ≤1º) with a 2D image collected at each position. Once 300-600 images have been collected a computational algorithm is used to produce a 3D model of the structure. Changes in the total attenuation of the transmitted particles (photons or neutrons) are recorded and can be subsequently interpreted. Since the attenuation of material varies according to both its position in the periodic table, and with its density, such a facility can be used to image damage (holes or voids) in a material, precipitates (particles of one material within another), or the internal structure of objects.
SCIENTIFIC BACKGROUND
Computed Tomography (CT) has been used since the 1970s in the medical field, but has witnessed increasing use in industry and archaeology as a powerful technique to non-destructively test and study materials. While the performance limitations of x-ray medical CT scanners are well understood, the range of samples encountered in materials research presents unique problems, especially when the samples are dense and/or composed of high-Z materials that fail to allow adequate transmission of conventional x-ray sources. Gamma and neutron sources allow the penetration of materials that lower energy x-rays (<400 KeV) cannot and so have enormous potential in many industrial and archaeological applications. In addition, digital tomosynthesis or limited-angle tomography holds out the promise of tomographic images without the need to rotate the object across 180º. This technique is of tremendous importance where a) the sample cannot be physically rotated across 180º, b) there is limited/no transmission in some angular ranges, and c) exposure times make the collection of projections across 180º time/cost prohibitive.
The student will carry out experiments with concrete samples, as well as archaeological artifacts, and compare and contrast gamma and neutron imaging of the same samples. In addition, each sample will be reconstructed over limited to angles to evaluate the potential of tomosynthesis for preliminary inspection of materials.
RESEARCH OBJECTIVE
(1) To create various concrete samples with various types and concentrates of aggregate and to image the samples with both Gamma and Neutron sources at the KGH Cancer Centre at the SLOWPOKE-2 reactor at RMC. Following imaging, the data will be reconstructed and the various aggregate materials identified and measured in volume rendering software.
(2) To induce cracking on the aggregate samples and to identify these cracks using limited-angle tomography (tomosynthesis).
(3) To image archaeological concretions, many from shipwrecks, where metal artifacts have been heavily corroded and the corrosions and mineralization products have entirely obscured the original artifact.
EXPERIENCED ENABLED
The student will become familiar with Gamma and Neutron CT data acquisition, reconstruction and segmentation.
BACKGROUND REQUIRED
Completed 3rd year MME.
Use of Laser Absorption to Measure Particle Cloud Density
SUPERVISOR
G. Ciccarelli
INTRODUCTION
The study of particle cloud dispersion by a shock wave is important to many applications, including multiphase explosives that comprise a condensed explosive surrounded with packed micrometric reactive metal particles.
SCIENTIFIC BACKGROUND
Experiments are currently underway looking at the shock acceleration and dispersion of a fine particle cloud. The experiments are carried out in a shock tube that is equipped with high-speed visualization. A 75,000 frames per second camera is used to track the dispersion and acceleration of the particle cloud after the interaction with the shock wave. A laser absorption technique will be used to obtain the density of the cloud at different positions in the shock tube as a function of time. The technique involves directing a beam of light from a Helium-Neon laser through the cloud and measuring the light intensity using a photo-diode.
RESEARCH OBJECTIVE
The light attenuation through the cloud is proportional to the particle cloud density. The project will involve setting up a simple laser-diode system and calibrating it. The calibration is done by dispersing a known amount of particles in a tank, of known volume, and measuring the laser light attenuation through the cloud.
EXPERIENCED ENABLED
The student will learn about shock tubes and associated diagnostics including: piezoelectric pressure sensors, schlieren photography, and simple laser diode operation.
BACKGROUND REQUIRED
No background knowledge is required, just a general interest in fluid flow and compressible flow in particular.
Solar Focusing Induced Damage to Automotive Lamps
SUPERVISOR
B. Surgenor (tentative)
INTRODUCTION
Solar focusing is a phenomena that can cause heat damage to the bevels of automotive headlamps. A local manufacturer is trying to come up with a reliable way to predict solar focus damage in ellipsoidal projector lamps. They have been working on the problem since 1997 and over the years the most common fix is to install a heat shield. Problems continue to arise with new lamp designs and the manufacturer would like to take a more scientific approach to the problem.
SCIENTIFIC BACKGROUND
The problem of solar focusing is not well documented for automotive applications. An apparatus was constructed (see Figure 1) to investigate the problem. The apparatus uses a bulb that emits more IR than the sun. Thus, for the same irradiation, the bulb’s spectrum is more damaging to the lamp bezel than the sun’s spectrum. Furthermore, since the collection efficiency of the parabola is not constant, the irradiance is a function of the distance from the bulb. The operator needs to use a pyranometer to establish an area that averages 1300 W/m2. This location is sensitive to slight shifts in position.
Figure 1. Solar focusing test apparatus.
RESEARCH OBJECTIVE
To investigate the relationship between lamp design and the degree of solar focus damage. The first step is to review the test protocol for the apparatus and determine whether modifications are warranted. Ideally, tests results will be confirmed with thermal optic simulation software.
EXPERIENCED ENABLED
The student will become familiar with the phenomena of solar focusing and will gain experience in the use of test apparatus to obtain empirical knowledge of physical phenomena.
BACKGROUND REQUIRED
ME1 with a strong interest in engineering research and hands-on experimentation.
CFD of Specialized Exhaust Components for Gas Turbine and Diesel Engines
SUPERVISOR
A.M. Birk with W.R. Davis Engineering Ltd., Ottawa, Ontario
INTRODUCTION
Dr. Birk works closely with an Ottawa based Engineering and Manufacturing firm (W.R. Davis Engineering Ltd, www.Davis-Eng.com, see web site for details) involved with the development of specialized exhaust components and systems for gas turbines and diesel engines. These systems are typically applied in Marine and Aerospace applications.
SCIENTIFIC BACKGROUND
Preliminary CFD studies are needed of the following before experimentation and prototype development are conducted:
i. f ilm and effusion cooling for exhaust system components
ii. advanced mixing and hyper-mixing nozzles for ejectors
iii. analysis of bent oblong ejected ducts
iv. s-bend diffusing ducts with effusion cooling
v. cold flow experiments of ejectors using 7-hole pressure probes
Dr. Birk is looking for students that are interested in any one of these areas. Further details of the study will be specified in writing before the project is initiated.
RESEARCH OBJECTIVE
The research objectives for each project are
- to study the performance of specific device configurations
- to develop modelling strategies and methods for the specific problem.
- to predict device performance over a range of conditions
- to identify experiments necessary to verify modeling methods and results
- to identify key design issues
The following tasks are planned for each project
- review of Fluent capability for subject matter
- develop CFD models and conduct grid, turbulence and convergence studies
- conduct parametric runs
- analyze data
- plan experiments for verification
- prepare report
EXPERIENCED ENABLED
The student will become familiar with Fluent. All of the above projects can be carried forward as MSc or PhD projects at Queen’s if the student and supervisor are in agreement.
BACKGROUND REQUIRED
Mech 341, Mech 330, Mech 346, Mech 444. You should also be taking Mech 439 in the winter term.
Evaluation of a Micromechanical Device for Testing of Individual Bone Trabeculae
SUPERVISOR
G.A.Dumas
INTRODUCTION
Mechanical properties of cancellous bone are of great clinical importance. Cancellous bone is at the interface with prostheses and can be the cause of prosthesis failure due to stress shielding or other mechanisms. Cancellous bone is also the common site of fracture in individuals suffering from osteoporosis. Mechanical properties of cancellous bone and its failure mechanisms are related to both its structure (struts and plates) and the mechanical properties of bone tissue itself. Evaluating tissue properties is therefore of great importance and necessitates to test individual structural elements, e.g. bone trabeculae.
SCIENTIFIC BACKGROUND
Testing of bone trabeculae is a technical challenge because of the small size of the specimens; trabeculae are typically a few millimeters long and less than a millimeter wide in large animals. Another challenge is gripping of the ends of the specimen without creating artifacts. Three point bending may therefore be an interesting alternative to conventional testing modes of tension and compression, and should be evaluated. One approach is to test specimens of size comparable to bone trabeculae and made of materials of known properties in the range of the values expected for bone tissue. Such materials include plastics and, on the upper end, possibly some metals such as copper. Plastics properties may vary substantially from batch to batch. Therefore, it would be necessary to determine the elastic modulus from larger specimens on a conventional materials testing machine. The results from specimens of trabeculae-like dimensions made from the same plastic block could be compared to this “gold standard” for the evaluation of the three-point bending testing apparatus.
RESEARCH OBJECTIVE
The objective of this research project is to evaluate the accuracy and reproducibility of a three-point bending apparatus designed to test bone trabeculae. The method will consist in comparing values obtained for the elastic modulus of materials of similar mechanical properties (plastics) obtained by conventional testing and with the apparatus.
EXPERIENCED ENABLED
The student will become familiar with material testing methods, specimen preparation, and data analysis.
BACKGROUND REQUIRED
Completion of third year, ME1, ME2 or ME3.
Mechanical Properties: New quantitative analysis to correlate performance with processing history
SUPERVISORS
B.J. Diak and S. Saimoto
INTRODUCTION
The advance in microstructural characterization using optical, X-ray and electron metallography has been enormous in the last three decades but that for mechanical properties has not advanced since the 1950's. The problem is that there has been no quantifiable method to microstructurally interpret the stress-strain curve as it yields, work-hardens and reaches the ultimate tensile stress initiating diffuse necking and localization to failure.
SCIENTIFIC BACKGROUND
Recently a new constitutive relation has been derived to replicate the stress-strain behaviour [Acta Mater. 59(2010)pp.602-612} in which digitally obtained stress-strain data can be quantitatively analyzed to correlate with the observed microstructure, processing history and its product performance. The methodolgy has already been carried for a diverse range of alloys AA1100, AA3003, AA5754, gamma-iron, austenitic stainless steel, and zircaloy-4 at various strain rates and temperatures to illustrate the method's robustness. This analysis permits the estimation of the deformed structure cell size, as well as point defect generation to form nano-voids.
RESEARCH OBJECTIVE
The student researcher will be given a mechanical data set for which the metallographic characterization has been performed, and re-analyze the mechanical data with respect to yield point elongation, UTS and overall ductility. Experiments with plane-strain testing will need to be performed to confirm the predictions of ductile failure, although some for stainless steel is available in the literature.This work will ultimately be used by industrial clients to enable inductive development of new alloys and processes.
EXPERIENCED ENABLED
The student will become familiar with constitutive relations in metals processing, advanced data analysis techniques, and mechanical testing.
BACKGROUND REQUIRED
Completion of third year, ME2.
Vision Based Machine Fault Monitoring
SUPERVISOR
B. Surgenor
INTRODUCTION
Machine vision (MV) is commonly used in manufacturing applications for automated inspection of part quality. A local manufacturer is interested to see if MV could also be used for machine fault monitoring. Typically, automation equipment employs many different types of sensors to monitor machine health. It has been suggested that a MV based system could reduce the number of sensors required for monitoring, as well as make the machine ‘smarter’ by enriching the data used for fault detection.
SCIENTIFIC BACKGROUND
The problem of MV fault detection is not well documented for automation equipment. A table top conveyor apparatus is available for test purposes (see Figure 1). The apparatus sorts plastic and metal pucks. Although rudimentary, the apparatus possesses features found in industrial PLC controlled conveyor systems. Potential faults include: 1) puck feeder - puck hangs up, 2) height gauge - misclassification, 3) pedestal feeder - pedestal fails to land squarely and 4) infrared counter - miscounts
Figure 1. Machine fault test apparatus.
RESEARCH OBJECTIVE
To investigate the ability of a webcam based MV system to identify “visually cued” machine faults. The first step is to collect an image library of fault free and faulty operation with the conveyor apparatus. A fault detection algorithm will then have to be developed and tested on-line. The image processing libraries in MATLAB and LABVIEW will be used as the basis for the algorithm.
EXPERIENCED ENABLED
The student will become familiar with the difficulties associated with machine fault detection and will gain experience in machine vision technology and PLC controlled automation equipment.
BACKGROUND REQUIRED
Strong interest in machine automation and machine vision systems.
How Does the Pigeon Control its Head: Feed-forward or Feedback?
SUPERVISORS
Q. Li and N. Troje (Department of Psychology)
INTRODUCTION
If birds are perched or move on the ground, head movements seem to be planned and executed in world coordinates external to the reference frame of the body. The body has to follow. That means that every movement, be it actively executed by the bird or passively induced by external forces requires active adjustments of the head by means of the neck muscles. The body – head system of the bird thus forms an interesting control system (check out this video for an entertaining demonstration: http://www.youtube.com/watch?v=_dPlkFPowCc).
SCIENTIFIC BACKGROUND
Birds have two different sensory systems which can measure accelerations. One is part of the inner ear and thus moves along with the head. The other system is located in the lower spine and moves with the body. Both systems could in principle be used to provide sensory signals to be used for head control. If the system located in the head is used, a feedback controller is required whereas if perturbation of the body is measured directly with a body fixed system, a feed-forward controller could be used. We set out to answer this question using a control system frame work and model the movement of the head with a simple discrete dynamic system.
RESEARCH OBJECTIVE
The objective of this research project is to understand head stabilization in the pigeon by analyzing the kinematic data obtained after controlled perturbations of body position and orientation. Perching pigeons will be perturbed by either moving them linearly for small amplitudes or rotating them about a vertical axis for small angles. We then measure the compensatory head movements by means of a motion capture system. The data are then fit with feed-forward and feedback control models. Through analysis, we expect to determine which mechanism is most likely been used by the bird. After this first analysis, we will be verifying our results in situations in which pigeons move actively as they walk on a treadmill. These experiments will be conducted in Dr. Troje’s Biomotion laboratory.
EXPERIENCED ENABLED
The student will acquire skills in performing interdisciplinary research, motion analysis for avian terrestrial locomotion, operating a complex real-time motion capture system, and applying control theory to a biological model.
BACKGROUND REQUIRED
A strong background in modeling and control theory, and an interest in studying bird locomotion.
Performance Evaluation on Inertial Sensor-based Walking Speed Estimation Methods
SUPERVISOR
Q. Li
INTRODUCTION
Gait speed has been used as an important indicator for evaluating locomotor performance and recovery from chronic diseases. Gait speed is often measured in the clinic but it is unknown whether clinic-measured speed can predict community walking speed. Therefore, it is important to measure gait speed in a daily living environment. There are commercial available devices such as NiKE+ Ipod and IPhone Apps, but they do not provide stride-by-stride gait information and the performance varies between users. There is strong need to develop a clinically-valid ambulatory gait speed estimation system.
SCIENTIFIC BACKGROUND
Recently, accelerometers, gyroscopes or their combination (Inertial measurement unit or IMU) have been used to estimate temporal and spatial gait parameters. In general, temporal parameters were estimated by detecting different invariant signal features of the measurements such as sharp peaks occurring during heel strike. Spatial parameters such as stride length can be estimated either indirectly or directly. In the indirect method, body-mounted sensors were used to estimate absolute angles of body segments. By using geometry and simple gait model, the stride length was calculated based on the estimated body segment angles. Due to the physiological variability of the model, frequent subject-to-subject calibration procedure was required. The other technique for spatial gait parameter estimation is direct double-integration of the acceleration signals. IMU has been attached to different body segment including the foot, the shank, the thigh, and the trunk. Although each method has its own merits and shortcomings, the effects of sensor attachment locations on the speed estimation performance has not been thoroughly evaluated.
RESEARCH OBJECTIVE
The objective of this research project is to evaluate the performance of several existing IMU-based walking speed estimation methods. To achieve the goal, the following tasks will be performed: (1) data collection with subjects walking on treadmill at different speeds with sensors attached at different locations. (2). Walking speed estimation algorithm development and performance comparison.
EXPERIENCED ENABLED
The student will become familiar with inertial sensor measurements, data acquisition. IMU signal processing, and human subject experimentation design and data analysis. The student will also enhance MATLAB programming skill.
BACKGROUND REQUIRED
Student with strong MATLAB programming skill and an interest in biomechanical measurements and signal processing. Mech 496 will be an asset.
Classifying Locomotor Activities with a Single Miniature Inertial Sensor
SUPERVISOR
Q. Li
INTRODUCTION
As human being, we perform different locomotor activities in our daily living environment. These activities include level ground walking, running, stair climbing, stair descending, walking on inclined surface, walking on declined surface, standing and etc.. Although the association between locomotor activity and positive health benefits has been established, quantifying locomotor activity in daily living environment has proven to be a difficult task.
SCIENTIFIC BACKGROUND
Previous studies have used vision-based system with single or multiple video cameras for activity recognition, and it is still the most common method. The usage of camera-based method is acceptable when the activities are confined to a limited area with sufficient light. As the space for performing physical activity is limited, the subject may react unnaturally. Recent advancement of microelectronics and signal processing technology has made miniature wireless sensors able to collect kinematics-related information in an unconstrained environment. Unlike camera systems providing position information, the inertial sensors measure the accelerations and angular velocities. Can we use a single inertial sensor to classify the motion during daily activities? Does single sensor provide sufficient information for discriminating different locomotion activities?
RESEARCH OBJECTIVE
The objective of this research project is to develop a pattern recognition technique to classify different locomotor activities using a single inertial sensor attached to the shank segment. The inertial sensor will measure the acceleration and angular velocity of the shank. From the measured acceleration and angular velocity, we will extract features related to different type of locomotion activities. Characteristics that differentiating different type of motion such as level walking, stair climbing, and stair descending will be derived. A computer program will be developed to classify the types of motions a subject is performing.
EXPERIENCED ENABLED
The student will become familiar with the inertial sensor data acquisition, signal processing and statistical data analysis as well as human experiment design. The student will also enhance MATLAB programming skill.
BACKGROUND REQUIRED
Mech 496 and strong MATLAB programming skill and an interest in biomechanical measurements and signal processing.
Fluid Flow and Mass Transport in Membrane
Separation
SUPERVISORS
J.G. Pharoah and A. Pollard
INTRODUCTION
Typical separation processes employ spiral wound membrane elements which use plastic spacers to create a flow channel between adjacent membranes. This results in channels with repeating cylindrical obstacles in a variety of arrangements, and these spacers can result in enhanced mixing as well as increased pressure drops.
SCIENTIFIC BACKGROUND
The role of membrane spacers is commonly misunderstood in the literature, wherein they are often called turbulence promoters, and their effect on mass transport is often inferred from predictions of the shear stress on the channel walls. In actuality, it is the advective mixing promoted by the separated flow behind these structures as well as the acceleration of the flow around the obstacles (which increases the shear stress at the wall) which results in enhanced performance. Ongoing work in our lab has used the open source CFD code OpenFOAM to perform Direct Numerical Simulation (DNS), or unsteady calculations resolving all relevant spatial and temporal scales, to simulate flow an mass transfer in spacer filled channels. To date, the mass transfer calculations have been simplified by using a Schmidt number of 1, and a constant wall flux. In reality, the Sc number for salt water is approximately 700 and the local flux is strongly dependent on the local concentration. High Sc simulations will require even finer meshes owing to the extremely small concentration boundary layers.
RESEARCH OBJECTIVE
The goal of this research is to run OpenFOAM DNS simulations with increasing SC, and to assess the suitability of the existing meshes. If feasible, finer meshes can be created. Finally, a new boundary condition could be implemented coupling the local flux to the local concentration.
EXPERIENCED ENABLED
The student will become familiar with running large scale parallel computer codes (64 processors is likely) on SHARCNET. They will also become familiar with DNS simulations and OpenFOAM.
BACKGROUND REQUIRED
Desire to work on OpenFOAM (written in c++). Experience with Fluid Mechanics and CFD.
Fluid Flow and Mass Transport in Membrane Separation
SUPERVISOR
J.G. Pharoah
INTRODUCTION
Water transport is a critical issue in the performance of PEM fuel cells, yet our understanding of multi-phase flow in these systems is still being developed. Water in a fuel cell is produced in the catalyst layer, and must be transported through a porous media before it emerges in the gas channels to be exhausted from the system. The physics in these systems is complicated, involving multi-phase flow with phase change in compressible porous media.
SCIENTIFIC BACKGROUND
The multi-phase flow in PEM fuel cells is strongly dependent on the properties of the porous media between the flow channels and the catalyst layer, and on the resulting temperature field which develops between the catalyst and the flow field plate. An apparatus for exploring this has been developed and simulates the PEM fuel cell environment by injecting water of a specified temperature into a porous media. A well controlled flow field is placed over top of the porous media, and controlled at a different temperature if desired. The system is transparent, such that a high speed camera can be used to capture the liquid water dynamics in the channel as a function of temperature gradient, water injection rate (current density), porous media properties, channel flow rates, temperatures and relative humidities. Additionally, the water can be seeded with a fluorescent dye and illuminated with a laser sheet in order to enhance contrast. This technique is similar to Laser Induced Fluorescence (LIF).
RESEARCH OBJECTIVE
The objective of this project is debug and debug and use the device to develop a map of multi-phase flow regimes (plug-flow, droplet flow, mist flow) as a function of temperature gradient and flow channel conditions. The work will be additionally supervised, by a Masters student who is using the rig for his research.
EXPERIENCED ENABLED
The student will become familiar with lasers, flow visualization and multi-phase fluid dyanamics.
BACKGROUND REQUIRED
Fluid Mechanics.
Sorption of Water and Electrical Conductivity in PEMFC Membranes and Catalyst Layers
SUPERVISORS
J.G. Pharoah and B.A. Peppley
INTRODUCTION
Ion conducting polymers (ionomers) are important components of PEM fuel cell membranes and catalyst layers. The conductivity of ionomer, which significantly
influences fuel cell performance, strongly depends on the water sorbed by the polymer. Therefore, investigation of the relation between the amount of sorbed water and electrical conductivity of the ionomers in membranes and catalyst layers is imperative.
SCIENTIFIC BACKGROUND
Water sorption from ionomers exposed to water vapour is conventionally measured by weight gain using analytical balances or quartz crystal microbalances. Though this is a direct way of measuring the amount of sorbed water, these methods do not allow for simultaneous measuring of the sample resistivity. However, experiments performed in our laboratory have demonstrated that the conductivity of membranes and catalyst layers at lower humidity depends not only on RH but also on RH history. This can lead to significant disagreement between sorption and conductivity data if they are collected in different independent experiments. Therefore, simultaneous measurement of water sorption and electrical conductivity is imperative. Water sorption by ionomers in PEMFC catalyst layers has not been investigated.
RESEARCH OBJECTIVE
The simultaneous measurement of the amount of sorbed water at different partial pressure of water vapour (sorption isotherm) and in-plane ionic conductivity of PEMFC membrane or catalyst layers will be carried out. Water sorption isotherms will be obtained by measuring changes in partial pressure of water vapour, rather than by weight gain of sample. This allows the attachment of probe wires to the experimental sample for in-plane electrical resistance measurement.
EXPERIENCED ENABLED
The student will gain a familiarity with PEM fuel cells and components as well as analytic experience in analytic techniques for water sorption and electric conductivity. The work will be carried out at the Fuel Cell Research Centre with additional supervision from a staff research assistant.
BACKGROUND REQUIRED
Determining Transport Properties in Porous Ceramic Fuel Cell Electrodes (Solid Oxide Fuel Cells)
SUPERVISOR
J.G. Pharoah
INTRODUCTION
Solid Oxide Fuel Cells (SOFC) are solid state electrochemical devices which convert the chemical energy of a fuel directly to electricity through electrochemical reactions. While they can be fed with a variety of fuels, the most common fuel currently is methane which can come either from natural gas distribution networks from biogas derived from landfills, wastewater, or gasification. The electrodes are made up of porous ceramics or ceramic metal composites called cermets, and these electrodes are necessarily porous in order to transport gases to the reaction sites while the solid matrix transports electrons/ions and heat.
SCIENTIFIC BACKGROUND
A variety of theoretical and empirical methods are available for estimating transport properties in porous media. These transport properties include thermal conductivity, mass diffusivity and electric conductivity. Unfortunately, these methods are suitable for either regular geometries or for random distributions of spheres. SOFC electrodes are far more complex than this, comprising multiple materials with various particle size distributions and are further complicated by the geometric changes which occur during high temperature sintering. An accurate determination of transport properties in such geometries is needed in order to understand and optimize fuel cell operation.
RESEARCH OBJECTIVE
The goal of this research is to use an computer program written in our research group to generate random SOFC electrode geometries and to solve for transport of heat, mass, and charge in these geometries. Through this process it is possible to estimate effective transport properties in the porous media and ultimately to correlate the data for use by others.
EXPERIENCED ENABLED
The student will become familiar with running computer codes written in C and Fortran as well as with visualization software. They will also get a good introduction to transport phenomena and contribute the development of an exciting class of fuel cells.
BACKGROUND REQUIRED
Desire to work on computer programming
Creep of an Alloy Proposed for Next Generation Nuclear Power Plants
SUPERVISOR
M.R. Daymond
INTRODUCTION
Zirconium alloys represent a materials system of major importance to the nuclear power industry, due to their good mechanical properties, excellent corrosion resistance in high temperature water, and low absorption of neutrons. A single commercial reactor will have around 100 km of tubing made from various zirconium alloys. Understanding potential failure and optimizing material processing and design to minimize failure is therefore critical.
SCIENTIFIC BACKGROUND
An advanced two phase zirconium based alloy “Excel”, composed of Zr-3.5%Sn, 1%Nb, 1%Mo, is being considered for the pressure tubes for Generation-4 CANDU reactors. At the temperatures involved, the material will undergo dislocation based creep.
RESEARCH OBJECTIVE
The objective of the research is to determine the creep-rupture (i.e. stress vs time to failure) characteristics of the material in the temperature range 200-400C.
EXPERIENCED ENABLED
The student will become familiar with thermomechanical testing, use of the image correlation technique for strain measurement, and data analysis approaches.
BACKGROUND REQUIRED
3rd year MME completed, MECH370 and/or MECH371 preferred.
Design and Testing of a Waste Plastic Extruder for Open Source Rapid Prototyper
SUPERVISOR
J.M. Pearce
INTRODUCTION
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Traditionally, 3-D printing has been used for rapid prototyping, where good tolerances, durability and fast print times dominate the user requirements. For this reason, commercial rapid prototyping machines are used in many industries to make custom parts for design-stage products and are able to perform operations such as printing a working ball bearing using overhangs and two material deposition methods. Recently, the development of open-source rapid prototypers, such as the RepRap, have made rapid prototyping inexpensive enough to be accessible to home users and potentially useful for open source appropriate technology (OSAT). Commercial printers excel at rapidly producing high-tolerance representations of complex parts; however, they are far more expensive ($5000-$200,000) than the ~$1,000 RepRap. Also as proprietary rapid prototypers generally have proprietary feedstocks, they are also extremely expensive ($1/in3 to $4/in3), while ABS plastic, often used for the RepRap (www.reprap.org), is strikingly less expensive at $0.032/in3. The goal of this project is to push open source rapid prototypers even further – to use waste plastic as a feedstock rather than preformed ABS filament.
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SCIENTIFIC AND ENGINEERING BACKGROUND
It is has been recently proposed that open source 3D printers could be used to drive sustainable development [J. M Pearce, C. Morris Blair, K. J. Laciak, R. Andrews, A. Nosrat and I. Zelenika-Zovko, “3-D Printing of Open Source Appropriate Technologies for Self-Directed Sustainable Development”, Journal of Sustainable Development 3(4), pp. 17-29 (2010). http://www.ccsenet.org/journal/index.php/jsd/article/view/6984 ] . For this to become realistic it is critical that feed stocks be developed from locally-available materials in order to prevent the erosion of cost advantages for local production. Using locally-available materials for fabricating OSAT not only ensures the community in question will be less dependent on foreign assistance if there are problems with the technology, but it also creates a sense of empowerment as technology is not handed out as a form of charity furthering dependence on foreign aid. This can be accomplished through the use of feedstocks created from waste products (e.g. plastic bags or bottles) or through the use of available local materials such as bio-polymers. The sheer abundance of plastics in household waste (including bags, bottles, food and entertainment packaging) is a reality in most non-rural communities, but this waste can be reused. A process could be used to create a waste-plastic filament for use in the RepRap. Thus a plastic extruder, which could heat the plastics and extrude them as a filament that can be used by the 3-D printer, is necessary. It should be noted that producing filament feedstock is a challenge as the diameter has to be precise and the filament must be very round (not oval) or the extruder will produce poor quality parts or jam as has been often encountered when RapMan owners buy replacement filament locally. A hopper-designed extruder may not be as dependent on the size properties of the material and also reliable advances in using pellet feed stock combined with a pelletizer is another option that can be explored.
RESEARCH OBJECTIVE
The objective of this research project is to design, build and test an extruder for the RepRap that can take polymer waste as a feedstock. Specifically the material properties of the printed objects will be tested to ensure that the design goals have been met.
EXPERIENCED ENABLED
The student will become familiar with engineering design, prototyping, sustainable development, and materials engineering.
BACKGROUND REQUIRED
Completion of third year, ME1 or ME2.
Investigation of Nano-void Nucleation in Age Hardenable Aluminum Alloys
SUPERVISOR
B.J. Diak and S. Saimoto
INTRODUCTION
In metal fabrication ductile fracture often limits the useable shape that a material can formed into. T materials engineering challenge is to understand the mechanisms of ductile failure such that metal processing practice can be modified to defer this inevitable result. In the aluminum industry, a curious correlation has been realized between the engineering yield stress and the strain measured at the point of fracture: (1) the yield stress characterizes the microstucture which act as obstacles to dislocation passage prior to mass dislocation accumulation; and (2) the fracture strain which normally exceeds a shear strain of unity is associated with the voids which grow with plastic deformation until triaxial stresses. This data appears to apply to both hardenable and non-hardenable alloys. However decades of such study have not provided sufficient enlightenment of the deformation processes to impact the industry beyond trial-and-error successes.
SCIENTIFIC BACKGROUND
An in-house crystal plasticity approach to formulate a new constitutive relation for plasticity has shown that point defect generation (vacancies and voids) can approach 2-3 % volume fraction at the fracture strains. Furthermore once voids of 2 to 3 nm are nucleated then depending on the inter-void spacing they can grow to micro-meter range as a linear function of strain. The required validation is to show that the starting nuclei diameters need to be less than 100 nm to detectably affect the total elongation to fracture. Since age-hardening derives from precipitation of nano-particles and its approximate spacing correlates to the yield stress, these nano-particles may be acting as inherent heterogeneous sites for nano-void formation.
RESEARCH OBJECTIVE
Age hardenable AA6111 is used for automobile skins and manifests the correlation between yield stress and fracture strain describe previously. To investigate its origin, tensile specimens will be solutionized and quenched into naturally- and artificially-aged conditions. Optimum ageing conditions can be selected and one or two such specimens deformed to necking but before failure. Sectioning along the tensile axis will allow bulk strain along the sheet centre to be approximated. Advanced imaging tools will be used to look for nano-voids greater than 20 nm and their size and distribution correlated with strain.
EXPERIENCED ENABLED
The student will become familiar with aluminum alloys, mechanical testing, advanced metallography and image analysis.
BACKGROUND REQUIRED
4th Year ME2.
Classifying Locomotor Activities with Multiple Miniature Inertial Sensors
SUPERVISOR
Q. Li
INTRODUCTION
As human being, we perform different locomotor activities in our daily living environment. These activities include level ground walking, running, stair climbing, stair descending, walking on inclined surface, walking on declined surface, standing and etc.. Although the association between locomotor activity and positive health benefits has been established, quantifying locomotor activity in daily living environment has proven to be a difficult task.
SCIENTIFIC BACKGROUND
Previous studies have used vision-based system with single or multiple video cameras for activity recognition, and it is still the most common method. The usage of camera-based method is acceptable when the activities are confined to a limited area with sufficient light. As the space for performing physical activity is limited, the subject may react unnaturally. Recent advancement of microelectronics and signal processing technology has made miniature wireless sensors able to collect kinematics-related information in an unconstrained environment. Unlike camera systems providing position information, the inertial sensors measure the accelerations and angular velocities. Hopefully we could identify the type of locomotor activity from these measurements.
RESEARCH OBJECTIVE
The objective of this research project is to develop a pattern recognition technique to classify different locomotor activities. The lower-limb kinematic data will be collected with a wireless inertial sensor-based motion capture system (Xsens MOVEN) during subject performing different locomotor activities. From the measured accelerations and angular velocities, features will be first extracted. As the initial set of features will be quite large, and not all features are equally useful in discriminating between activities, a principle component analysis-based feature reduction will be performed. Finally, a Bayesian decision making (BDM) or k-Nearest neighbor (k-NN) based classification methods will be used to classify the activities.
EXPERIENCED ENABLED
The student will become familiar with the inertial sensor-based motion capture system. Signal processing and statistical data analysis. The student will also enhance MATLAB programming skill.
BACKGROUND REQUIRED
Mech 496 and strong MATLAB programming skill and an interest in biomechanical measurements and signal processing.
Energy and Carbon Footprint of Manufacturing a Part
SUPERVISOR
J. Jeswiet
INTRODUCTION
The resource intensity and impact of industry is clear considering that it represents 47% of energy use, 19% of gross water use (Ontario accounts for 46%) and 32% of carbon dioxide (CO2) emissions in Canada in 2008. Growing economic, social and environmental challenges are driving the new paradigm of sustainable development, in which competitive sustainable manufacturing (SM) will play a key role. It has been suggested that energy monitoring of machining equipment can be used to improve energy efficiency and reduce carbon footprint of a product in the manufacturing phase of its life cycle.
SCIENTIFIC BACKGROUND
Currently, there are two milling machines equipped with current and voltage dataloggers that require the OMEGA software interface to access the data. These can be used to acquire the overall power consumption of the machine. Although real-time power and energy monitoring equipment are becoming available, there is still difficulty in relating the energy use to specific machining parameters. This is needed to consider minimum energy and carbon footprint optimization. Furthermore, apart from electricity, coolants, lubricants and workpiece materials also provide sources of carbon.
RESEARCH OBJECTIVE
To investigate the effect of changing machining parameters (e.g. speeds and feeds) for cutting or forming and the design of a specific part on its energy and carbon footprint. Either of two machines can be used for the analysis and a part can be chosen from various available designs. One machine available performs milling (HAAS TM-1) whilst the other (Bridgeport) currently is set up to perform single point incremental forming (SPIF). The OMEGA software will be used for data acquisition, whilst Excel and MATLAB will be needed to analyse the data and produce relationships. Of specific interest is determining what components in the machine have constant versus variable power consumption. If data acquisition and analysis are well-timed, MATLAB can be used to perform an optimization algorithm.
There is a possibility for 2 student projects, one done on each machine.
EXPERIENCED ENABLED
The student will become familiar with the difficulties associated with power measurement and carbon emission accounting for machining in part manufacturing. As such, the student will gain experience in measurement methodology and machining design to improve energy efficiency and reduce carbon footprint.
BACKGROUND REQUIRED
Completion of 3rd year MME and strong Microsoft Excel and MATLAB skills. Familiarity with MASTERCAM will be helpful. Furthermore, an interest in manufacturing strategy, sustainable manufacturing and carbon footprint is desirable.
CFD of Dispersion of a Tracer Gas Near a Piping Leak
SUPERVISOR
R.W. Sellens
INTRODUCTION
Piping assemblies and other engineered fluid systems must be tested for leaks to ensure safe and continuous functioning in operations. Leak testing has included hydrostatic testing, pressure decay testing with gases and tracer gas detection of leaks. Various tracer gases have been considered, including helium and hydrogen, which can be detected in the air around the part using various detectors. One of the variables affecting detector performance is the local concentration of tracer gas at the detector position, which depends on both the nature of the leak and the ambient airflow in the vicinity of the system under test.
SCIENTIFIC BACKGROUND
Low concentrations of tracer gas may be modeled as a passive scalar diffusing in an otherwise homogeneous, incompressible gas flow. Existing Computational Fluid Dynamics (CFD) code packages such as OpenFOAM or Fluent can provide good solutions for low speed airflows with solid boundaries, including the potential for source terms representing leaks.
RESEARCH OBJECTIVE
Complete a CFD simulation for concentration of a passive tracer gas in air around a pipe joint. Variables will include ambient air velocity and direction, and tracer gas composition. The resulting field will be interrogated to answer the research questions:
“What are the limitations on localization of a leak imposed by ambient environment, tracer gas choice, detector sensitivity and response time?”
“How close must a detector get to the leak and for how long in order to reliably detect the existence of a leak?”
EXPERIENCED ENABLED
The student will further develop their skills in CFD modeling and extracting useful engineering information from the results.
BACKGROUND REQUIRED
Completion of third year, ME1, ME2 or ME3, plus MECH 341 and CFD experience from a course or project.
Experimental Evaluation and Refinement of a Desiccant Dehumidification System
SUPERVISOR
S. Harrison
INTRODUCTION
In many worldwide locations, including Canada, energy consumption for air-conditioning is dominated by dehumidification or “latent” loads. In conventional air-conditioning systems, humid air is cooled by refrigeration to condense-out excess moisture. The resultant cold, saturated air-stream must then be reheated to the desired end-user conditions. This process can be inefficient and waste primary energy. An alternative is to separate the dehumidification and “sensible” cooling processes. One way to accomplish this is to use desiccant solutions to chemically absorb the water vapour from an air-stream, and then to separately cool this “dried” air-stream with a small capacity chiller or by evaporative cooling.
SCIENTIFIC BACKGROUND
A small-scale liquid-desiccant dehumidification system was constructed in the Solar Lab at Queen’s and instrumented to investigate its performance under a limited range of conditions. The unit used a water/Lithium-chloride (LiCl ) solution. LiCl is hygroscopic in nature, i.e., it absorbs moisture from the air. In a liquid desiccant dehumidifier, the desiccant solution is sprayed into an air-stream, absorbing moisture. The “wet” desiccant solution then is regenerated by heating it, thereby driving off the unwanted moisture. Heating for this process can be provided from a “waste” heat source or by solar energy.
RESEARCH OBJECTIVE
Based on a previously completed study, the objective of this research project is to experimentally characterize the existing prototype liquid-desiccant dehumidification unit under controlled laboratory conditions. The unit will be operated under a variety of supply and load conditions and its performance characteristics determined including moisture removal rates and thermal and electrical, Coefficients of Performance, (COP’s). A conclusion of the previous study was that modifications are required to improve the performance of the device’s regenerator; specifically a heat exchanger should be added to preheat the desiccant solution prior to entering the regenerator. Evaluating this concept will be an objective of the proposed study. In addition, experimental results will be compared against an updated computer model of the unit. The results of this study will be summarized in a final report.
EXPERIENCED ENABLED
The student researcher will gain experience in advanced HVAC systems, experimental design and measurements techniques, as well as, the analyses and presentation of test data.
BACKGROUND REQUIRED
MECH 330 and MECH 346 (or permission of the instructor).
(Recovery and) Recrystallization of AA3XXX and AA6XXX
SUPERVISOR
B.J. Diak
INTRODUCTION
Light metallic alloys such as those derived from Al, Mg or Ti are used in areas where demand for specific strength is required such as in the transportation sector. The use of these metals is often limited in more mundane applications as automobiles due to cost, unless the performance needs are exceptional.. In terms of raw material cost, Al alloys are the cheapest of the three, and therefore are the most likely to find their way into new lighter designs for automobiles if they can meet the processing and structural requirements. Processing demands that the material can be processed into the near net shape of the object of interest, usually by deformation, into a structure which can provide the necessary mechanical response.
SCIENTIFIC BACKGROUND
Aluminum AA6XXX are designed to offer some range of formability, but more importantly can increase its strength significantly by age hardening processes involving the alloying elements Mg-Si-Cu. The precipitation response of these alloys is highly dependent upon the small fraction of deformation stored in the material, which upon heating is removed from the material resulting in recovery and recrystallization processes. These processes will be quite different in hea treatable (AA6xxx) and non-heat treatable alloys (AA3XXX).
RESEARCH OBJECTIVE
Measure the recovery and recrystallization response of cold rolled AA6XXX and AA3XXX after the same amount of pre-strain to determine and compare the kinetics affecting the processes. The measurements will be examined in the context of the models of Verdier or Nes.
EXPERIENCED ENABLED
The student researcher will gain experience in advanced heat treating practice, mechanical testing, and x-ray and electron scattering characterization.
BACKGROUND REQUIRED
ME2
Experimental Evaluation of a Dual-medium Solar Thermal Collector
SUPERVISOR
S. Harrison
INTRODUCTION
The use of solar energy is rapidly becoming a viable alternative to traditional energy generation methods. Used efficiently, solar technology could reduce both residential and industrial conventional energy demands. Solar thermal collectors convert the sun’s radiation into thermal energy. They are typically used for space and water heating (by heating a circulating liquid) or for preheating building make-up air. Traditionally, purpose-built solar collectors have been configured to use either a liquid, or an air-based, working fluid. In this project, a solar collector designed to separately, or simultaneously, heat both air and liquid will be examined. This configuration should increase the functionality and operation of a solar system. It could potentially increase the utilization of solar energy, improving system efficiency and cost performance.
SCIENTIFIC BACKGROUND
A unique solar collector with an integrated stagnation control has been designed and commercialized by a Canadian company [www.EnerWorks.com]. Specifically, the collector utilizes an air channel behind the absorber plate to reject heat during potential overheating (e.g., stagnation) conditions. This project will experimentally investigate the feasibility of using this design as a “dual mode” solar thermal collector capable of pre-heating make-up air, as well as, liquid for use in domestic hot water, and radiant floor, heating.
RESEARCH OBJECTIVE
Following on an initial configuration proposed in a previously completed Mech 460 project [ B. Jessup, C. Kemp, B. Kukreja, S. Seemann (2010). Dual Medium Solar Collector Design, ME 460 Project Final Report, Queen’s University, 2010. ], the objective of this study is to experimentally characterize a prototype of the dual-medium collector operating under controlled conditions. The unit will be instrumented and evaluated using both mediums (i.e., water/glycol and air). In particular, the thermal efficiency in each operational mode, e.g., liquid-only, air-only, and combined-mode will be determined. Time permitting; the pressure drop characteristics versus air flow rate will be determined for the air-mode operation. The experimental results obtained during this project will also be used to refine a thermal model developed as part of the aforementioned Mech 460 project.
EXPERIENCED ENABLED
The student researcher will gain valuable knowledge of solar driven thermal systems, experimental design, measurement techniques, along with data analysis and presentation.
BACKGROUND REQUIRED
MECH 330, MECH 346, and MECH 430 (or permission of instructor).
Linear Friction Welding of Structural Steel
SUPERVISORS
D. Boyd, K. Pilkey
INTRODUCTION
Linear friction welding (LFW) is solid-state joining of materials by relative motion of two components under compressive forces. The advantages of LFW compared with fusion welding processes are significantly reduced weldment widths (1-2 mm) and elimination of chemical contamination and coarse microstructures. To date, LFW has only been utilized for high value-added aircraft engine components. Effort is required to apply this novel joining technique to more widely-used structural materials.
SCIENTIFIC BACKGROUND
The LFW process involves plastic deformation of metal alloys under conditions of temperature, strain and strain rate, which could produce strain hardening, dynamic recovery/recrystallization, static recovery/recrystallization and grain growth. The exact sequence of these microstructural mechanisms determines the final microstructure, and hence the mechanical properties of the weldment. Thus, for a given material, it is necessary to characterize the weldment microstructure, in order to optimize the LFW process parameters.
RESEARCH OBJECTIVE
The objective of the research is to characterize the weldment microstructures of LFW samples of a structural steel, produced under 2 different welding conditions. (LFW samples have been provided by NRC-NAE Aerospace Technology Manufacturing Centre, Montreal.) Tensile and Charpy properties of the welded samples will be determined and correlated with the microstructure observations.
EXPERIENCED ENABLED
The student will acquire hands-on knowledge of experimental design, metallographic techniques, mechanical testing, data analysis and reporting/presentation of results.
BACKGROUND REQUIRED
3rd yr. MME completed, including MECH 370 and MECH 371.
Investigation of Inter-trial Variability of Joint Angle Estimation Using Inertial Sensor Based System on an Instrumented Gimbal
SUPERVISOR
Q. Li
INTRODUCTION
Joint angle estimations are an important quantitative measurement for human mobility analysis. It can be used in characterizing human gait and to distinguish the difference between a healthy subject with normal gait and one with a paralytic mobility disability. It is also important in evaluating the functional ability of a subject following rehabilitation. Motion capture systems are currently the standard instrumentation for estimating joint angles. However, due to the physical limitations, cost, ambulatory limitations and data collection limitations of motion capture systems, inertial based sensor systems are currently emerging as a substitute.
SCIENTIFIC BACKGROUND
The combination of accelerometers, gyroscopes, and magnetometers are called Inertial Measurement Units (IMUs), and are capable of measuring position, orientation, and motion of an entire human subject. In order to validate inertial sensor based systems as a substitute to motion capture systems, the accuracy of each system must be compared. Previous studies have been limited to estimating 2D knee joint angles, flexion/extension using pendulum devices or human subjects to quantify the accuracy of IMU based sensors in planar motion. Recent studies have compared IMU based systems with magnetic marker systems. However a direct comparison between the systems is methodically impossible since both systems measure joint angles indirectly. Using an instrumented gimbal, it is possible to directly quantify the accuracy of the inertial sensor based system. The current interest is to systematically quantify and determine the repeatability of the inertial sensor based system.
RESEARCH OBJECTIVE
To develop a dynamic finite element contact model of tibiofemoral knee joint that corresponds with the instrumented tibial implant. The model should predict knee contact loading for a variety of experimentally measured conditions, and the force predictions will be compared with actual measurements.
EXPERIENCED ENABLED
The student will become familiar with contact modeling, and will learn to generate solid models from 3D imaging data. The student will enhance capabilities in MATLAB, and will learn to use state-of-the-art biomechanical modeling software: OpenSim.
BACKGROUND REQUIRED
3rd yr. MME completed.
Finite Element Modeling of an Instrumented Knee Prosthesis
SUPERVISOR
K. Deluzio
INTRODUCTION
Many mathematical models have been developed to estimate the forces experienced by knee joint during a variety of activities. However, validation of these models is difficult because it is highly invasive (and technically challenging) to take direct measurements in a living person. Over the last decade, a few researchers have addressed this challenge by incorporating telemetric instrumentation into a prosthesis for subjects who require an invasive knee replacement surgery. These directly measured loads can be used to develop more accurate models of knee joint loading.
SCIENTIFIC BACKGROUND
Computed Tomography (CT) imaging data can be used to reconstruct the geometry of the knee implant as well as its orientation relative to the leg bones. An existing model of the leg will provide the external loading conditions for a finite element model of the instrumented prosthesis. Some critical challenges in the model include sensitivity to misalignment between components, and indeterminate force-sharing with the ligaments and other soft tissues.
RESEARCH OBJECTIVE
To develop a dynamic finite element contact model of tibiofemoral knee joint that corresponds with the instrumented tibial implant. The model should predict knee contact loading for a variety of experimentally measured conditions, and the force predictions will be compared with actual measurements.
EXPERIENCED ENABLED
The student will become familiar with contact modeling, and will learn to generate solid models from 3D imaging data. The student will enhance capabilities in MATLAB, and will learn to use state-of-the-art biomechanical modeling software: OpenSim.
BACKGROUND REQUIRED
A keen interest in biomedical engineering, and proficiency in MATLAB. Previous experience in finite element analysis will also be an asset.
Thermal Conductivity in PEMFC Membranes
SUPERVISOR
J. Pharoah
INTRODUCTION
As both modeled and experimentally measured, the operating proton exchange membrane fuel cell (PEMFC) is not isothermal. This is due to the fact that virtually all of the heat is generated in the membrane electrode assembly (MEA), which is literally insulated by carbon PTLs (Porous Transport Layers). In order to achieve effective control of the cooling of fuel cells, knowledge of the through-plane thermal conductivity of these materials is vital.
SCIENTIFIC BACKGROUND
Measurement of the thermal conductivity of PTL materials is complicated for several reasons. The in-plane thermal conductivity is likely to be different from the through-plane. The through-plane thermal conductivity, the thermal contact resistance (1 / h), and the thickness change with the applied compaction pressure. Residual water in the pores significantly changes both the thermal conductivity and the thermal contact resistance. Therefore, care must be taken when measuring the thermal conductivity of PTLs.
The original experiments were carried out by inserting thermocouples directly inside the fuel cell. Results were obtained from a simplified thermal model. The relatively large thermocouples increase uncertainty in the temperature gradient determination in these measurements. The current apparatus measures the temperature of the sample as it is sandwiched between copper plates and takes into account the thicknesses of the sample at different compaction pressures.
RESEARCH OBJECTIVE
The objective of this research project is to take part in the development of an apparatus designed to measure the thermal conductivity of PEMFC Porous Transport Layers used in fuel cells under various pressures. The student will be responsible for the completion of its construction, calibration and testing of the apparatus. LABVIEW will be used in the data acquisition system.
EXPERIENCED ENABLED
The student will gain a familiarity with PEM fuel cells and components as well as analytic experience in analytic techniques for thermal conductivity. The work will be carried out at the Fuel Cell Research Centre with additional supervision from a staff research assistant.
BACKGROUND REQUIRED
MECH346 some experience with LABVIEW.
Dynamic Mechanical Properties of Silicones
SUPERVISORS
B. Diak and R. Anderson
INTRODUCTION
Polymers and elastomers can play an important role in isolating sensitive components from challenging environments. Silicone potting compounds are frequently used to seal electron components to keep out heat, moisture, reduce vibration, and maintain some opaqueness to light for quick visual inspection.
SCIENTIFIC BACKGROUND
Silicones are elastomers which can be easily moulded to different shapes, and display excellent adhesion, chemical and moisture resistance, excellent mechanical resilience and very good electrical insulating properties. Their behaviours depends significantly upon their chemistry and processing history.
RESEARCH OBJECTIVE
Different silicone compounds will be prepared with voids and no void mixing. The thermal coefficient of linear expansion, temperature depednent dynamic loss modulus, and high 'g' vibration absorption performance will be measured for these epoxies and compared to simple composite models.
EXPERIENCED ENABLED
The student will become familiar with sample preparation, sensitive mechanical measurement instrumentaiton and techniques, dynamic properties of materials, and microscopy.
BACKGROUND REQUIRED
MECH371
