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Full-Text Articles in Mechanical Engineering

Design Of A Pool Access Device, Linjun Bu, Patrick Graham May 2013

Design Of A Pool Access Device, Linjun Bu, Patrick Graham

Assistive Technology Resource Center Projects

A pool chair was designed using the 2010 ADA standards for accessible design. The design uses a parallel four-bar linkage mechanism and is able to lift the chair with an average weight person in and out of the pool. The motion of the design has been analyzed. The motion is achieved by an electronic linear actuator. The analysis of the motion of this design yields reasonable transmission angles of 73° to 110°.


Design Of A Powered Hand Orthosis, Elyssa Dorenfeld, Robert Wolf, Stephan Zeveska Apr 2013

Design Of A Powered Hand Orthosis, Elyssa Dorenfeld, Robert Wolf, Stephan Zeveska

Assistive Technology Resource Center Projects

The goal of this project was to design and manufacture a fully functional powered hand orthosis, controlled and operated by the contralateral hand, and used by people with diminished hand functions. Linear actuators were used to create the movement of the fingers through a six-bar linkage. The design reduces the twenty seven degrees of freedom in a healthy human hand to six and replicates the motions needed to perform the most common grips including the cylindrical, pinch, and key grips. Results showed that a single finger could exert a force of 50N. This correlates to an approximate hand strength of ...


Motorsports Safety, Anthony Begins, Korapat Lamsam, Kerrie Maron Apr 2013

Motorsports Safety, Anthony Begins, Korapat Lamsam, Kerrie Maron

Assistive Technology Resource Center Projects

The prevalence of neck injuries and basilar skull fractures in motorsports caused many sanctioning bodies in top-tier auto-racing divisions to mandate the use of head and neck restraints. Current devices inhibit drivers from exiting the car in emergencies, such as a fire or situation where emergency medical personnel are needed. The Motorsports Safety group designed and prototyped a new head and neck restraint device that can be removed easily while wearing a racing helmet by releasing a wing via a quick release mechanism. Evaluation of the prototype demonstrated that the time to remove the device via the quick release was ...


Shoulder Mount For A Wearable Arm Orthosis, Richard Downey, Nikole Dunn, Adam Hoyt Apr 2013

Shoulder Mount For A Wearable Arm Orthosis, Richard Downey, Nikole Dunn, Adam Hoyt

Assistive Technology Resource Center Projects

Functionality of the upper limb is vital for performing Activities of Daily Living (ADLs) such as bathing, dressing, and eating. The goal of this project was to design, manufacture, test, and evaluate a shoulder mount to be used in conjunction with a powered, upper-limb orthosis. A prototype was developed that allows completion of all necessary ADLs, is user-friendly, and does not significantly increase the user’s body frame. On average, the device limits the user’s shoulder flexion and abduction by approximately 43% and 50%, respectively, and is reasonably adjustable to both male and female users in the 25th to ...


Atrc Communications, Anthony Begins, Stephan Zeveska May 2012

Atrc Communications, Anthony Begins, Stephan Zeveska

Assistive Technology Resource Center Projects

The Assistive Technology Resource Center (ATRC) at Worcester Polytechnic Institute (WPI) was founded in 1999 to serve as a regional provider of assistive devices, services, and engineering solutions. A need existed for the ATRC to develop an improved framework to communicate with the WPI and outside communities. This project created a framework to enable the ATRC's operation to be self-sustainable and re-establish regular communications. Templates were developed for the informational brochure, newsletter and website. The Rehabilitation Engineering Laboratory was reorganized and procedures were developed to standardize the operation for future use. The results of this project will enable the ...


Pseudo-Fluid Control Extension System, John Dunbar, Christopher Farren, Mari Freitas Apr 2012

Pseudo-Fluid Control Extension System, John Dunbar, Christopher Farren, Mari Freitas

Assistive Technology Resource Center Projects

A pseudo-fluid control extension system was created to manipulate a medical device. The device had the ability to control a transesophageal echocardiogram transducer (TEE) from a distance of five feet. Designs were created using cable and hydraulic systems, but both systems were problematic. A pseudo-fluid system consisting of tubes filled with steel balls was developed to capture the positive aspects of cable and fluid systems. The user interface consisted of two rotatable knobs that actuate rack and pinion gear sets, which push the pseudo-fluid balls through tubes. At the distal ends of the tubes, the balls move the racks of ...


Rowing Foot Stretcher Design, John Madura, Daniel Pierson Apr 2012

Rowing Foot Stretcher Design, John Madura, Daniel Pierson

Assistive Technology Resource Center Projects

In crew racing shells, the foot stretcher attaches the shoes, providing a surface for the rower to push off. Background research, collected from patents, rower surveys, and safety requirements, identified several aspects of current foot stretchers that could be improved. A design was developed using solid modeling and axiomatic design, analyzed using FEA, and machined using CNC. User testing was conducted to ensure ergonomic and power requirements were met. Based on the results of testing 8 rowers, and design analysis, this project’s design was found to make the rower more comfortable, regardless of gender, ability, and rower size. Furthermore ...


Effects Of Processing Residual Stresses On Fatigue Crack Growth Behavior Of Structural Materials: Experimental Approaches And Microstructural Mechanisms, Christopher J. Lammi, Diana Lados Jan 2012

Effects Of Processing Residual Stresses On Fatigue Crack Growth Behavior Of Structural Materials: Experimental Approaches And Microstructural Mechanisms, Christopher J. Lammi, Diana Lados

Mechanical Engineering Faculty Publications

Fatigue crack growth mechanisms of long cracks through fields with low and high residual stresses were investigated for a common structural aluminum alloy, 6061-T61. Bulk processing residual stresses were introduced in the material by quenching during heat treatment. Compact tension (CT) specimens were fatigue crack growth (FCG) tested at varying stress ratios to capture the closure and Kmax effects. The changes in fatigue crack growth mechanisms at the microstructural scale are correlated to closure, stress ratio, and plasticity, which are all dependent on residual stress. A dual-parameter ΔK-Kmax approach, which includes corrections for crack closure and residual stresses, is used ...


Numerical Simulation And Experimental Validation Of Residual Stresses In Water-Quenched Aluminum Alloy Castings, Bowang Xiao, Keyu Li, Qigui Wang, Yiming Rong Dec 2011

Numerical Simulation And Experimental Validation Of Residual Stresses In Water-Quenched Aluminum Alloy Castings, Bowang Xiao, Keyu Li, Qigui Wang, Yiming Rong

Mechanical Engineering Faculty Publications

Aluminum alloy castings are normally water quenched after solution treatment to improve mechanical properties. Rapid water quenching can result in high-residual stress and severe distortion which significantly affect functionality and performance of the products. To optimize product design and durability, one needs to model and predict residual stress and distortion produced in the water-quenched components. In this article, a finite element-based approach was developed to simulate the transient heat transfer and residual stress development during water quenching. In this approach, an iterative zone-based heat transfer algorithm was coupled with material constitutive model called mechanical threshold stress (MTS). With the integrated ...


Localized Recrystallization In Cast Al-Si-Mg Alloy During Solution Heat Treatment: Dilatometric And Calorimetric Studies, S. K. Chaudhury, V. Warke, S. Shankar, Diran Apelian Oct 2011

Localized Recrystallization In Cast Al-Si-Mg Alloy During Solution Heat Treatment: Dilatometric And Calorimetric Studies, S. K. Chaudhury, V. Warke, S. Shankar, Diran Apelian

Mechanical Engineering Faculty Publications

During heat treatment, the work piece experiences a range of heating rates depending upon the sizes and types of furnace. When the Al-Si-Mg cast alloy is heated to the solutionizing temperature, recrystallization takes place during the ramp-up stage. The effect of heating rate on recrystallization in the A356 (Al-Si-Mg) alloy was studied using dilatometric and calorimetric methods. Recrystallization in as-cast Al-Si alloys is a localized event and is confined to the elasto-plastic zone surrounding the eutectic Si phase; there is no evidence of recrystallization in the center of the primary Al dendritic region. The size of the elasto-plastic zone is ...


An Experimental Study Of Heat Transfer During Forced Air Convection, Bowang Xiao, Gang Wang, Qigui Wang, Mohammed Maniruzzaman, Yiming Rong, Richard D. Sisson Jr. Oct 2011

An Experimental Study Of Heat Transfer During Forced Air Convection, Bowang Xiao, Gang Wang, Qigui Wang, Mohammed Maniruzzaman, Yiming Rong, Richard D. Sisson Jr.

Mechanical Engineering Faculty Publications

Cast aluminum alloys are usually subject to solution treatment, quenching, and aging hardening for improved mechanical properties. Cooling rate during quenching plays an important role in residual stress, distortion, and mechanical property distributions in the resultant cast aluminum components. As the cooling rates of work pieces heavily depend on the interfacial heat transfer coefficient (HTC) between work pieces and quenchants, it is important to understand how HTC varies with different quenching conditions so that optimal quenching process can be achieved. In this study, a quenching system and an experimental procedure of obtaining HTC are presented. A series of experiments have ...


Recent Advances In Microdevices For Transportation Industry, Ryszard J. Pryputniewicz Oct 2011

Recent Advances In Microdevices For Transportation Industry, Ryszard J. Pryputniewicz

Mechanical Engineering Faculty Publications

Advances in emerging technologies of microelectromechanical systems (MEMS) and nanotechnology, especially relating to the applications, constitute one of the most challenging tasks in today's micromechanics and nanomechanics. In addition to design, analysis, and fabrication capabilities, this task also requires advanced test methodologies for determination of functional characteristics of devices produced to enable verification/validation of their operation, as well as refinement and optimization of specific designs. In particular, development of microdevices requires sophisticated tools, especially as these devices apply to transportation industry because of stringent safety and reliability requirements. These tools can be categorized as analytical, computational, and experimental ...


Front Mounting Bicycle Attachment For Improved Accessibility Of Adult Passengers, Victor Montero, Kelly Roberge, Brandon Stuczko Apr 2011

Front Mounting Bicycle Attachment For Improved Accessibility Of Adult Passengers, Victor Montero, Kelly Roberge, Brandon Stuczko

Assistive Technology Resource Center Projects

Currently, no bicycle attachments are capable of transporting an adult passenger in front of a bicycle, which would significantly improve the passenger's range of vision and enjoyment. The goal of this project was to design a front mounting device that could accommodate adult passengers, including those with limited mobility, and could be adjusted to attach to different sized bicycle frames. The device frame was built out of 1" aluminum tubing and galvanized steel fittings and was attached to the bicycle through a compressive attachment mechanism. The driver's steering intuition was maintained through a 1:1 ratio in the ...


Design Of The Grab-Bot, Meaghan Busteed, Amanda Rinaldi Apr 2011

Design Of The Grab-Bot, Meaghan Busteed, Amanda Rinaldi

Assistive Technology Resource Center Projects

There is a need to develop an assistive device for persons who have difficulty reaching, retrieving, picking and placing objects in a household or office setting. Our goal is to design and prototype an electromechanically operated "grabber" to aid users in completing these tasks in the safest manner possible. A first generation prototype was successfully designed and manufactured utilizing several types of plastic and a simple circuit with DC motor. Testing has shown that the Grab-bot extends the user's reach by 2 feet and is designed to retrieve various objects weighing up to 2 pounds in a safe manner ...


Design Of A New Prosthetic Alignment Adaptor With Quantitative Alignment And Height Adjustment, Olufunmilayo Adebayo, Lydia George, Mark Marchand, Jeffrey Marrion Apr 2011

Design Of A New Prosthetic Alignment Adaptor With Quantitative Alignment And Height Adjustment, Olufunmilayo Adebayo, Lydia George, Mark Marchand, Jeffrey Marrion

Assistive Technology Resource Center Projects

After an amputation, a patient's prosthesis must be aligned with their body using an alignment adaptor. Current adaptors have two primary limitations: 1) the inability to adjust the vertical height during alignment, and 2) the inability to quantify the adjustments. Therefore, a new prototype adaptor was designed and manufactured that allows for adjustments in all six degrees of freedom, including height. In addition, a novel pin design allows for quantification of the alignment. The prototype was validated with prosthetist feedback and finite element analysis. A protocol for patient testing received IRB approval and is scheduled for the near future ...


Solution Treatment Effects On Microstructure And Mechanical Properties Of Al-(1 To 13 Pct)Si-Mg Cast Alloys, Diana A. Lados, Diran Apelian Feb 2011

Solution Treatment Effects On Microstructure And Mechanical Properties Of Al-(1 To 13 Pct)Si-Mg Cast Alloys, Diana A. Lados, Diran Apelian

Mechanical Engineering Faculty Publications

The effects of solution treatment time and Si content and morphology on microstructures and mechanical properties of heat-treated Al-Si-Mg cast alloys were investigated systematically. Five alloys, with Si levels ranging from 1 to 13 pct, were tested in as-cast, T4, and T61 conditions. The eutectic Si was both unmodified and Sr-modified. Results show that the microstructures are affected significantly by alloy composition, eutectic Si morphology, and solution treatment time. Si content has significant effects on ultimate tensile strength (UTS), yield strength (YS), and elongation as well as a strong influence on solution treatment response. In T61 treatment with different solutionizing ...


Aging Effects On Heat Treatment Response And Mechanical Properties Of Al-(1 To 13 Pct)Si-Mg Cast Alloys, Diana A. Lados, Diran Apelian, Libo Wang Feb 2011

Aging Effects On Heat Treatment Response And Mechanical Properties Of Al-(1 To 13 Pct)Si-Mg Cast Alloys, Diana A. Lados, Diran Apelian, Libo Wang

Mechanical Engineering Faculty Publications

The effects of artificial aging time on the mechanical properties of Al-Si-Mg cast alloys were investigated as a function of Si content and morphology. Five alloys with Si ranging from 1 to 13 pct, unmodified and Sr-modified, were tested systematically in as-cast, T4, and T61 conditions with different aging times. The results indicated that the ultimate tensile strength (UTS) and the yield strength (YS) increased with increasing aging time, and that the YS increased more than the UTS. The increase was low during the first 2 hours, significantly increased after 2 hours, and slowed down at similar to 10 hours ...


Optimizing The Wpi Assistive Technology Resource Center: Marketing And Documentation, Lydia George, Deepti Kalluri May 2010

Optimizing The Wpi Assistive Technology Resource Center: Marketing And Documentation, Lydia George, Deepti Kalluri

Assistive Technology Resource Center Projects

The Assistive Technology Resource Center (ATRC) at Worcester Polytechnic Institute (WPI) was created in 1999 with the mission to serve as a regional provider of assistive devices and services. The Center is unique in its ability to provide a technical aspect to the development of customized assistive technology to its clients. An IQP group, Lyons and Trimby (2008), reevaluated the operations of the ATRC nine years after its establishment. The team determined that one area to focus on would be the organization of past projects completed within the ATRC into a centralized database. A second IQP group, Hristov, Mawhiney, and ...


Improved Walker Design, Meagan Foley, Kelly Johnson, Joseph Kalbach, Brittany Mcnally Apr 2010

Improved Walker Design, Meagan Foley, Kelly Johnson, Joseph Kalbach, Brittany Mcnally

Assistive Technology Resource Center Projects

Over 41,000 people sustain injuries from falls while using a walker each year. An improved walker design that decreases the chance of falling was developed from background research and mathematical modeling of users' falls. Two improvements were embodied as universal accessories that can be attached to any standard walker. The accessories are lateral leg extensions, which temporarily extend the base of support (BOS) and a tactile and electronics guidance package, which indicates the users' location relative to the BOS. Eight volunteers evaluated and compared the prototype to a standard walker. The prototype reduced the occurrence of stepping outside the ...


Powered Device For Pushing A Manual Wheelchair, Kevin Kordosky, Lindsay Mullins, Katelyn Perkins, George Von Roth Apr 2010

Powered Device For Pushing A Manual Wheelchair, Kevin Kordosky, Lindsay Mullins, Katelyn Perkins, George Von Roth

Assistive Technology Resource Center Projects

The goal of this project was to design and prototype a cost-effective, powered, manual wheelchair-pusher that is easy to use, transportable, and satisfies the requirements of institutional and personal use. The device locks around a crossbar underneath the wheelchair and uses a battery-powered motor with a drive wheel and a manually controlled front wheel to steer. Testing confirmed the functionality of the pusher; further improvements to the device are recommended so that it may be used by an institution or individual.


History And Future Of Rehabilitation Robotics, Christopher Frumento, Ethan Messier, Victor Montero Mar 2010

History And Future Of Rehabilitation Robotics, Christopher Frumento, Ethan Messier, Victor Montero

Assistive Technology Resource Center Projects

With recent technological advances it has become possible to develop advanced artificial limbs for people with disabilities. This report gives a brief history of the field of Rehabilitation Robotics, and then reviews eight currently produced (either experimentally or commercially) robotic devices designed to assist patients with limb loss or in need of skeletal-muscular assistance. After detailing the use and operation of each device, this report assesses each device on the basis of eight criteria: cost, accessibility, maintainability, training, adaptability, safety, environmental concerns and technological possibility. Each device was given a ranking based on those criteria, and on the basis of ...


Investigation Of Rarefied Supersonic Flows Into Rectangular Nanochannels Using A Three-Dimensional Direct Simulation Monte Carlo Method, Nikolaos A. Gatsonis Mar 2010

Investigation Of Rarefied Supersonic Flows Into Rectangular Nanochannels Using A Three-Dimensional Direct Simulation Monte Carlo Method, Nikolaos A. Gatsonis

Mechanical Engineering Faculty Publications

The rarefied flow of nitrogen with speed ratio (mean speed over most probable speed) of S = 2,5,10, pressure of 10.132 kPa into rectangular nanochannels with height of 100, 500, and 1000 nm is investigated using a three-dimensional, unstructured, direct simulation Monte Carlo method. The parametric computational investigation considers rarefaction effects with Knudsen number Kn=0.481,0.962, 4.81, geometric effects with nanochannel aspect ratios of (L/H) from AR=1,10, 100, and back-pressure effects with imposed pressures from 0 to 200 kPa. The computational domain features a buffer region upstream of the inlet and ...


Optimizing The Wpi Assistive Technology Resource Center: Operation And Management, Stoyan Hristov, Kelsey Mawhiney, Zachary Wilson May 2009

Optimizing The Wpi Assistive Technology Resource Center: Operation And Management, Stoyan Hristov, Kelsey Mawhiney, Zachary Wilson

Assistive Technology Resource Center Projects

The Assistive Technology Resource Center (ATRC) at the Worcester Polytechnic Institute (WPI) originated with the intent to fill the need for a regional, specialized assistive technology hub, which would be a source for the technical information required in order to create customized assistive technology devices. As time has progressed, the Center has expanded and has aided many individuals with disabilities. This was done by creating new solutions to disability‐related issues that were not addressed in the past, primarily by designing new devices or modifying existing ones. After ten years of operation, it became necessary to re‐evaluate the operation ...


One-Arm Drive Manual Wheelchair, Dominic Digiovanni, Valerie Marrion, Hamlet Nina Apr 2009

One-Arm Drive Manual Wheelchair, Dominic Digiovanni, Valerie Marrion, Hamlet Nina

Assistive Technology Resource Center Projects

Traditional manual wheelchairs require considerable use and control of both arms for operation, thus adaptations are required for individuals with asymmetrical use of their arms. Building upon previous projects, the goal of this project was to create an accessory, to be installed on a standard wheelchair, which would allow full control of the wheelchair with only one arm/hand while addressing areas lacking in commercial products and previous designs, such as manufacturability, attendant control, user comfort and ergonomics. After preliminary testing and analysis of three one-arm propulsion designs (Meyra lever-operated chair, Quickie dual-pushrim chair, and the 2005-06 MQP’s prototype ...


Design And Manufacturing Of A Portable Single-Switch Activated Bowling Game, Jeff Prunera, Jacob Saffron, Jonathan Welch Apr 2009

Design And Manufacturing Of A Portable Single-Switch Activated Bowling Game, Jeff Prunera, Jacob Saffron, Jonathan Welch

Assistive Technology Resource Center Projects

The Seven Hills Pediatric Center in Groton, MA has asked for a bowling game that is designed for their residents whom all have special needs. It has been determined that there are four essential elements to this bowling game. These elements consist of: a ball launching mechanism, a ball catching device, a ball returning system, and some method for easing pin setup. The outcome of this project is a bowling system that can be easily stored, moved between rooms, and can be used on a daily basis.


A Model For Converting Dilatometric Strain Measurements To The Fraction Of Phase Formed During The Transformation Of Austenite To Martensite In Powder Metallurgy Steels, Virendra S. Warke, Richard D. Sisson, Makhlouf M. Makhlouf Mar 2009

A Model For Converting Dilatometric Strain Measurements To The Fraction Of Phase Formed During The Transformation Of Austenite To Martensite In Powder Metallurgy Steels, Virendra S. Warke, Richard D. Sisson, Makhlouf M. Makhlouf

Mechanical Engineering Faculty Publications

A model is developed to allow converting dilatometric strains that occur during the continuous cooling transformation (CCT) of austenite to martensite to volume fraction martensite formed in powder metallurgy steels. Unlike existing models, this model can accurately account for the observed decrease in the measured transformation strain with increased porosity. As a demonstration, the model is used to accurately calculate the volume fraction of martensite formed during the CCT of austenite to martensite in FL-4605 PM steel.


Estimation Of Spatially Distributed Processes Using Mobile Spatially Distributed Sensor Network, Michael A. Demetriou, Islam I. Hussein Jan 2009

Estimation Of Spatially Distributed Processes Using Mobile Spatially Distributed Sensor Network, Michael A. Demetriou, Islam I. Hussein

Mechanical Engineering Faculty Publications

The problem of estimating a spatially distributed process described by a partial differential equation (PDE), whose observations are contaminated by a zero mean Gaussian noise, is considered in this work. The basic premise of this work is that a set of mobile sensors achieve better estimation performance than a set of immobile sensors. To enhance the performance of the state estimator, a network of sensors that are capable of moving within the spatial domain is utilized. Specifically, such an estimation process is achieved by using a set of spatially distributed mobile sensors. The objective is to provide mobile sensor control ...


Effect Of Alloy Composition On Carburizing Performance Of Steel, Olga K. Rowan, Richard D. Sisson Jr. Jan 2009

Effect Of Alloy Composition On Carburizing Performance Of Steel, Olga K. Rowan, Richard D. Sisson Jr.

Mechanical Engineering Faculty Publications

This paper investigates the effect of alloy composition on the gas carburizing performance of AISI 1018, 4820, 5120, and 8620 steels. The mass-transfer coefficients and carbon diffusivities were calculated from experimental measurements using direct flux integration. Although steels with high concentration of austenite-stabilizing elements (Si, Ni) increased carbon diffusivity in austenite, they significantly reduced the kinetics of carbon transfer from the atmosphere to the steel surface and resulted in lower weight gain. Despite lowering the carbon diffusivities, steels alloyed with carbide-forming elements (Cr, Mo) significantly increased the mass-transfer coefficient in the atmosphere and enhanced the rate of carbon profile evolution ...


Lotka-Volterra Systems In Environments With Randomly Disordered Temporal Periodicity, Arvid Naess, Mikhail F. Dimentberg, Oleg Gaidai Aug 2008

Lotka-Volterra Systems In Environments With Randomly Disordered Temporal Periodicity, Arvid Naess, Mikhail F. Dimentberg, Oleg Gaidai

Mechanical Engineering Faculty Publications

A generalized Lotka-Volterra model for a pair of interacting populations of predators and prey is studied. The model accounts for the prey's interspecies competition and therefore is asymptotically stable, whereas its oscillatory behavior is induced by temporal variations in environmental conditions simulated by those in the prey's reproduction rate. Two models of the variations are considered, each of them combining randomness with "hidden" periodicity. The stationary joint probability density function (PDF) of the number of predators and prey is calculated numerically by the path integration (PI) method based on the use of characteristic functions and the fast Fourier ...


Manual Wheelchair Handbook Study For The Massachusetts Department Of Mental Retardation, Daniel Asselin, Nikolas Ledoux, David Willens May 2008

Manual Wheelchair Handbook Study For The Massachusetts Department Of Mental Retardation, Daniel Asselin, Nikolas Ledoux, David Willens

Assistive Technology Resource Center Projects

No abstract provided.