Mechanical Engineering Commons^™

Direct Numerical Simulations Of Non-Premixed Ethylene–Air Flames: Local Flame Extinction Criterion, Vivien R. Lecoustre, Paul G. Grias, Somesh P. Roy, Zhaoyu Luo, Dan C. Haworth, Hong G. Im, Tianfeng F. Lui, Arnaud Trouvé

Mechanical Engineering Faculty Research and Publications

Direct Numerical Simulations (DNS) of ethylene/air diffusion flame extinctions in decaying two-dimensional turbulence were performed. A Damköhler-number-based flame extinction criterion as provided by classical large activation energy asymptotic (AEA) theory is assessed for its validity in predicting flame extinction and compared to one based on Chemical Explosive Mode Analysis (CEMA) of the detailed chemistry. The DNS code solves compressible flow conservation equations using high order finite difference and explicit time integration schemes. The ethylene/air chemistry is simulated with a reduced mechanism that is generated based on the directed relation graph (DRG) based methods along with stiffness removal. The numerical configuration …

Evaluation Of Heat Recovery Options For Improved Energy Efficiency Of A Manufacturing Facility, Allison Chouinard

Master's Theses (2009 -)

Nationwide process heating in the manufacturing sector accounts for 7,815 trillion BTU of energy use annually; this is roughly one-third of the sector's total energy consumption [Energetics Incorporated, 2014]. The U.S. Department of Energy estimates that seventy percent of process heating is fueled by the onsite burning of fossil fuels [Energetics Incorporated, 2014]. These fuel-fired process heating applications are prime opportunities for heat recovery projects capable of saving energy and, consequently, reducing operating costs. This thesis evaluates different methods for heat recovery in the Milwaukee manufacturing facility of STRATTEC Security Corporation. As a basis for this work, the overall energy …

Nanogap Device: Fabrication And Applications, Jun Hyun Han

Dissertations (1934 -)

A nanogap device as a platform for nanoscale electronic devices is presented. Integrated nanostructures on the platform have been used to functionalize the nanogap for biosensor and molecular electronics. Nanogap devices have great potential as a tool for investigating physical phenomena at the nanoscale in nanotechnology. In this dissertation, a laterally self-aligned nanogap device is presented and its feasibility is demonstrated with a nano ZnO dot light emitting diode (LED) and the growth of a metallic sharp tip forming a subnanometer gap suitable for single molecule attachment.

For realizing a nanoscale device, a resolution of patterning is critical, and many …

Within-Socket Myoelectric Prediction Of Continuous Ankle Kinematics For Control Of A Powered Transtibial Prosthesis, Samuel Farmer, M. Barbara Silver-Thorn, Philip A. Voglewede, Scott A. Beardsley

Biomedical Engineering Faculty Research and Publications

Objective. Powered robotic prostheses create a need for natural-feeling user interfaces and robust control schemes. Here, we examined the ability of a nonlinear autoregressive model to continuously map the kinematics of a transtibial prosthesis and electromyographic (EMG) activity recorded within socket to the future estimates of the prosthetic ankle angle in three transtibial amputees. Approach. Model performance was examined across subjects during level treadmill ambulation as a function of the size of the EMG sampling window and the temporal 'prediction' interval between the EMG/kinematic input and the model's estimate of future ankle angle to characterize the trade-off between model error, …

Therapeutic Potential Of Haptic Theradrive: An Affordable Robot/Computer System For Motivating Stroke Rehabilitation, Andrew Theriualt, Mark L. Nagurka, Michelle J. Johnson

Mechanical Engineering Faculty Research and Publications

There is a need for increased opportunities for effective neurorehabilitation services for stroke survivors outside the hospital environment. Efforts to develop low-cost robot/computer therapy solutions able to be deployed in home and community rehabilitation settings have been growing. Our long-term goal is to develop a very low-cost system for stroke rehabilitation that can use commercial gaming technology and support rehabilitation with stroke survivors at all functioning levels. This paper reports the results of experiments comparing the old and new TheraDrive systems in terms of ability to assist/resist subjects and the root-mean-square (RMS) trajectory tracking error. Data demonstrate that the new …

Panel I: Connecting 2nd Law Analysis With Economics, Ecology And Energy Policy, Richard Gaggioli, Mauro Reini

Mechanical Engineering Faculty Research and Publications

The present paper is a review of several papers from the Proceedings of the Joint European Thermodynamics Conference, held in Brescia, Italy, 1–5 July 2013, namely papers introduced by their authors at Panel I of the conference. Panel I was devoted to applications of the Second Law of Thermodynamics to social issues—economics, ecology, sustainability, and energy policy. The concept called Available Energy which goes back to mid-nineteenth century work of Kelvin, Rankine, Maxwell and Gibbs, is relevant to all of the papers. Various names have been applied to the concept when interactions between the system of interest and an environment …

Modeling, Analysis, And Verification Of A Weld-Breaking Mechanism For Automatic Circuit Recloser Applications, Brian Korves

Master's Theses (2009 -)

The automatic circuit recloser (ACR) is responsible for protecting electrical distribution grids in the event that high voltage power lines come in contact with ground. In order to prevent damage, ACRs break the electrical continuity of the circuit through the use of a vacuum interrupter and a weld breaking mechanism. Vacuum interrupters consist of two metallic contacts in an air-tight ceramic housing. Due to the electrical interactions that take place during the interruption process, unintended welds are formed between the contacts. These welds have the ability to impede or completely stop the interruption process, thus rendering the ACR inoperable. In …

An Experimental Fatigue And Finite Element Study Of A Welded Joint Of A Snowplow Blade, George Ernest Selburg

Master's Theses (2009 -)

This study describes a method to evaluate the fatigue life of a welded joint of a snowplow. Fatigue specimens were then fabricated, which simulated the joint and its loading characteristics. The joint in the specimens were characterized by measuring the geometry of the weld and the hardness of the parent material, weld material, and heat affected zone. It was determined that the fatigue crack that developed in the joint was exposed to mode I fracture forces in the normal plane of the crack. The specimens were then tested in a hydraulic closed looped system to determine the mechanism of fatigue …

Design And Verification Of A Compact Variable Stiffness Actuator With A Very Large Range Of Stiffness, Daniel Garces

Master's Theses (2009 -)

Current conventional robots require high stiffness joints to provide absolute positioning accuracy in free space which also causes problems when operating in constrained space. To circumvent these problems, Variable Stiffness Actuators (VSAs) can be used to vary their stiffness to suit the task being performed. A new VSA was designed to provide a very large range of stiffness in a compact size. The Arched Flexure VSA uses a cantilevered beam acting as the flexure with a variable point of contact. It allows the joint to have continuous variable stiffness, have zero stiffness for a small range of motion, and rapid …

Design Of A Passive Ankle Prosthesis With Powered Push-Off Using A Cam Timing Mechanism, Jacob J. Rice

Master's Theses (2009 -)

This thesis presents the design and simulation results of the CamWalk, a novel passive prosthetic ankle that has mechanical behavior similar to that for a natural ankle. The CamWalk uses a compression spring network that allows coupling between two degrees of freedom; one for translation along the leg and another for rotation about the ankle joint. When walking, potential energy from the person's weight is stored in the spring network in deflection along the leg. The energy is released by the network as rotation of the foot. The amount of translational work that is converted to rotational work about the …

Determination Of A Predictive Stiffness Model For A 1 Dof Human Inspired Robotic Joint, Michael Boyarsky

Master's Theses (2009 -)

In order to facilitate more natural and intuitive interaction for human users, robots need to move in a more human-like manner as compared to current robots. This change would enable humans to better anticipate robot movements (which would allow humans to better avoid collisions if necessary) and also improve safety in the context of a collision between a robot and a human. The goal of this thesis was to analyze experimental data of human motion to gain an understanding of how human motion and robot motion differ. From this understanding, a neuro-motor model (NMM) of a human elbow (previously established …

Detailed Computational Modeling Of Laminar And Turbulent Sooting Flames, Adhiraj Dasgupta, Somesh Roy, Daniel C. Haworth

Mechanical Engineering Faculty Research and Publications

This study reports development and validation of two parallel flame solvers with soot models based on the open-source computation fluid dynamics (CFD) toolbox code OpenF0AM. First, a laminar flame solver is developed and validated against experimental data. A semi-empirical two-equation soot model and a detailed soot model using a method of moments with interpolative closure (MOMIC) are implemented in the laminar flame solver. An optically thin radiation model including gray soot radiation is also implemented. Preliminary results using these models show good agreement with experimental data for the laminar axisymmetric diffusion flame studied. Second, a turbulent flame solver is developed …

Helicopters As A Theme In A Machine Design Course, Devin Turner, Mark L. Nagurka

Mechanical Engineering Faculty Research and Publications

Helicopters as a Theme in Teaching Machine Design A machine design course is required in most undergraduate mechanical engineering curricula. This course generally covers an introduction to mechanical engineering design, a review of materials engineering, a review of mechanics of materials (shear force and bending moment diagrams, stress and strain analysis, deflection and stiffness analysis of beams, columns, etc.),models for failure due to static loading and variable fatigue, and then presents (in somewhat arbitrary order) the design of specific mechanical elements: shafts, fasteners, springs, bearings, gears, flexible elements such as belts, chain, and wire rope, clutches, brakes, couplings, etc. For …

Machine Design Experiments Using Mechanical Springs To Foster Discovery Learning, Peter William Malak, Mark L. Nagurka

Mechanical Engineering Faculty Research and Publications

Machine Design Experiments Using Mechanical Springs to Foster Discover Learning For the typical undergraduate engineering student the topic of mechanical springs is introduced and discussed in several courses. A first exposure may be in a physics course, where springs are presented as idealized mechanical energy storage components. Springs store potential energy,complementing masses that store kinetic energy and dampers that are resistive and offer no energy storage capability. In an electrical circuit course, springs are often presented as the analog of either capacitors or inductors, depending on which analogy is used. For mechanical engineering students, springs are a core component studied …

A One-Dimensional Model Of A Closed-Loop Refrigeration Test Block For Centrifugal Compressors, Paul D. Gessler

Master's Theses (2009 -)

The increasingly competitive building equipment and control industry pushes manufacturers to continually improve the performance and efficiency of their products to develop and maintain a competitive edge. Compressor development is an expensive endeavor, but the cost and time required for testing can be minimized by developing a model of the compressor test block to predict its behavior with a given prototype compressor at specified operating conditions. This thesis presents a thermodynamic model of a hot gas bypass test block used to evaluate centrifugal compressor performance at a compressor development facility. The test block uses cooling towers to reject the heat …

The Derivation Of Euler's Equations Of Motion In Cylindrical Vector Components To Aid In Analyzing Single Axis Rotation, James J. Jennings

Master's Theses (2009 -)

The derivation of Euler's equations of motion in using cylindrical vector components is beneficial in more intuitively describing the parameters relating to the balance of rotating machinery. Using the well established equation for Newton's equations in moment form and changing the position and angular velocity vectors to cylindrical vector components results in a set of equations defined in radius-theta space rather than X-Y space. This easily allows for the graphical representation of the intuitive design parameters effect on the resulting balance force that can be used to examine the robustness of a design. The sensitivity of these parameters and their …

Design And Development Of An Affordable Haptic Robot With Force-Feedback And Compliant Actuation To Improve Therapy For Patients With Severe Hemiparesis, Andrew R. Theriault, Mark L. Nagurka, Michelle J. Johnson

Mechanical Engineering Faculty Research and Publications

The study describes the design and development of a single degree-of-freedom haptic robot, Haptic Theradrive, for post-stroke arm rehabilitation for in-home and clinical use. The robot overcomes many of the weaknesses of its predecessor, the TheraDrive system, that used a Logitech steering wheel as the haptic interface for rehabilitation. Although the original TheraDrive system showed success in a pilot study, its wheel was not able to withstand the rigors of use. A new haptic robot was developed that functions as a drop-in replacement for the Logitech wheel. The new robot can apply larger forces in interacting with the patient, thereby …

Plastic Deformation Investigation Of High Energy Input Friction, Tao Yan

Dissertations (1934 -)

In this dissertation, plastic deformation of friction surfaces under high energy input is investigated. The plastic deformation of the friction surface and subsurface was studied and models were established to estimate deformation.

In order to calculate the plastic deformation at friction surface, an algorithm based on Ramberg-Osgood relationship was generated, and a single material model was developed based on this algorithm. Work hardening caused by plastic deformation and thermal softening caused by elevated temperature were considered in the model. To validate the model, an apparatus was designed to perform friction tests under different conditions. A special steel specimen with a …

Development Of High Fidelity Soot Aerosol Dynamics Models Using Method Of Moments With Interpolative Closure, Somesh Roy, P. G. Arias, Vivien R. Lecoustre, Daniel C. Haworth, H. G. Im, Arnaud Trouvé

Mechanical Engineering Faculty Research and Publications

The method of moments with interpolative closure (MOMIC) for soot formation and growth provides a detailed modeling framework maintaining a good balance in generality, accuracy, robustness, and computational efficiency. This study presents several computational issues in the development and implementation of the MOMIC-based soot modeling for direct numerical simulations (DNS). The issues of concern include a wide dynamic range of numbers, choice of normalization, high effective Schmidt number of soot particles, and realizability of the soot particle size distribution function (PSDF). These problems are not unique to DNS, but they are often exacerbated by the high-order numerical schemes used in …

Evaluation Of Forearm Muscle Fatigue From Operating A Motorcycle Clutch, Megan O. Conrad, Richard W. Marklin

Mechanical Engineering Faculty Research and Publications

A laboratory experiment evaluated the effect of motorcycle clutch design on the electromyography (EMG) activity of the primary agonist finger flexor muscle in the forearm. The goal was to compare muscle fatigue resulting from operation of two different motorcycle clutches in simulated traffic. EMG activity from the flexor digitorum superficialis (FDS) muscle of 12 female and 11 males were recorded while each participant operated an existing motorcycle clutch (requiring 98 N peak force) as well as an alternate design (requiring 36 N peak force) during 60-minute simulations. Muscle fatigue was quantified by measuring the decrease in median frequency of the …