Mechanical Engineering Commons^™

Uncertainty Analysis Of Mechanical Properties From Miniature Tensile Testing Of High Strength Steels, Deepthi Rao Malpally

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This Miniature mechanical testing study is concerned with the use of miniature specimens to identify the mechanical properties of stainless steel Type 304, sensitized Type 304 and SA516 Grade 70 carbon steel as a viable replacement for the standard sized mechanical testing. The study aims at obtaining suitable specimen geometry and tensile testing procedure for miniature mechanical testing whose mechanical properties are comparable to that of conventional specimens of ASTM A370-10 of the same steel. All specimens are at and the gauge length cross section will be varied to obtain suitable geometry. The miniature tensile testing results are further validated …

The Analysis And Manufacturing Of The Personal Vacuum Assisted Climber Ii, Rhet B. Astle

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Personal Vacuum Assisted Climber or PVAC for short (as shown in Fig 2) is a new means for climbing walls. Unlike ordinary climbing methods used today, the PVAC scales walls via suction. This suction is produced by three spinning impellers within each vacuum motor, which removes air from a sealed area. A climber pulls down on a vacuum pressure release mechanism to release the vacuum. Foot stirrups are used by the climber to climb to the next higher step. This allows the strength of the climber's legs to lift his/her body reducing arm fatigue, allowing rapid ascension of any …

Experimental Studies Of Delta Wing Parameters In Open Channel Raceway Determined Via Validated Computational Fluid Dynamics, Cole David Blakely

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A promising feedstock for biofuels is microalgae. The most economical means of cultivating microalgae is via open raceway ponds. However, a large gap in economic feasibility exists between algae-based biofuels and traditional petroleum fuels. Recent research at Utah State University has focused on increasing biomass growth by implementing Delta Wings (DWs). DWs are placed facing the incoming flow, with a 40 degree angle of attack to create large vortices which travel downstream. The trailing vortices increase vertical mixing, which in turn increases algal growth.

Past researchers at USU quantified vertical mixing with new metrics, optimized various raceway operating conditions, and …

Bridging The Nano- And Macro-Worlds: Thermal Property Measurement Using Thermal Microscopy And Photothermal Radiometry – Application To Particle-Irradiation Damage Profile In Zirconium Carbide, Colby Bruce Jensen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Multiscaled experimental investigations of heat transfer from nanoscales to macroscales are requisite to progress in energy technologies. In nuclear applications, material properties can undergo significant alteration due to destructive interaction with irradiating particles at microstructural levels that affect bulk properties. This study expands the current knowledge base regarding thermal transport in ion-irradiated materials through the use of a multiscaled experimental approach using four complementary thermal wave methods. For the first time, the in-depth thermal conductivity profile of an ion-irradiated sample is measured directly.

Numerical Examination Of Flux Correction For Solving The Navier-Stokes Equations On Unstructured Meshes, Dalon G. Work

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This work examines the feasibility of a novel high-order numerical method, which has been termed Flux Correction. This is accomplished by comparing it against another high-order method called Flux Reconstruction. These numerical methods are used to solve the Navier-Stokes equations, which govern the motion of fluid flow. High-order numerical methods, or those that demonstrate a third-order and higher solution error convergence rate, are rarely used on unstructured meshes when solving fluid problems. Flux Correction intends to make high-order accuracy available to the larger world of Computational Fluid Dynamics in a simple and effective manner. The advantages and disadvantages of the …

Asymmetric Unilateral Transfemoral Prosthetic Simulator, Tyagi Ramakrishnan

USF Tampa Graduate Theses and Dissertations

amputation, which includes reduced force generation at the knee and ankle, reduced control of the leg, and different mass properties relative to their intact leg. The physical change in the prosthetic leg leads to gait asymmetries that include spatial, temporal, or force differences. This altered gait can lead to an increase in energy consumption and pain due to compensating forces and torques. The asymmetric prosthesis demonstrated in this research aims to find a balance between the different types of asymmetries to provide a gait that is more symmetric and to make it overall easier for an amputee to walk.

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Numerical Simulation Of Flow In Ozonation Process, Jie Zhang

USF Tampa Graduate Theses and Dissertations

In the last two decades, Computational Fluid Dynamics (CFD) has shown great potential as a powerful and cost-efficient tool to troubleshoot existing disinfection contactors and improve future designs for the water and wastewater treatment utilities.

In the first part of this dissertation two CFD simulation methodologies or strategies for computing turbulent flow are evaluated in terms of the predicted hydraulic performance of contactors. In the LES (large eddy simulation) methodology, the more energetic, larger scales of the turbulence are explicitly computed or resolved by the grid. In the less computationally intensive RANS (Reynolds-averaged Navier-Stokes) methodology, only the mean component of …

Design And Analysis Of Hydrogen Powered Actuator Integrating Metal Hydride Storage System, Md Mainul Hossain Bhuiya

UNLV Theses, Dissertations, Professional Papers, and Capstones

The multi-fold purposes of this dissertation consists of construction, simulation and validation of a model describing hydrogen sorption kinetics in metal hydride. The project involves a comprehensive review of engineering applications involving metal hydrides and furthermore, design and investigation of a thermo-kinetically driven actuation system integrating metal hydrides for compact and soft robotic actuation. This will also shed some light on the feasibility of designing a damping system integrating metal hydride. Firstly, a mathematical model along with comprehensive simulation strategy of hydrogen absorption and desorption processes in porous metal hydride compacts was developed. A two dimensional axisymmetric model was built …

Tailsitter Attitude Control Using Resolved Tilt-Twist, Timothy Mclain, Jason M. Beach, Matthew E. Argyle, Randall W. Beard, Stephen Morris

Faculty Publications

The tailsitter aircraft merges the endurance and speed of fixed-wing aircraft with the flexibility and VTOL abilities of rotorcraft. Because of the requirement to be functional at a full range of attitudes, quaternions are typically employed to calculate attitude error. Attitude control is then accomplished by using the vector component of the error quaternion to drive flight control surfaces. This paper demonstrates that this method of driving the flight control surfaces can be suboptimal for tailsitter type aircraft and can lead to undesired vehicle movement. An alternate method of calculating attitude error called resolved tilt-twist is improved and validated. The …

Anisotropy Of The Reynolds Stress Tensor In The Wakes Of Counter-Rotating Wind Turbine Arrays, Nicholas Michael Hamilton

Dissertations and Theses

A wind turbine array was constructed in the wind tunnel at Portland State University in a standard Cartesian arrangement. Configurations of the turbine array were tested with rotor blades set to rotate in either a clockwise or counter-clockwise sense. Measurements of velocity were made with stereo particle-image velocimetry. Mean statistics of velocities and Reynolds stresses clearly show the effect of direction of rotation of rotor blades for both entrance and exit row turbines. Rotational sense of the turbine blades is visible in the mean spanwise velocity W and the Reynolds shear stress -[macron over vw]. The normalized anisotropy tensor was …

A Sinteractive Ni-Bazr0.8Y0.2O3-Δ Composite Membrane For Hydrogen Separation, Shumin Fang, Siwei Wang, Kyle S. Brinkman, Fanglin Chen

Faculty Publications

BaZr_0.8Y_0.2O_3−δ (BZY) is an excellent candidate material for hydrogen permeation membranes due to its high bulk proton conductivity, mechanical robustness, and chemical stability in H₂O- and CO₂-containing environments. Unfortunately, the use of BZY as a separation membrane has been greatly restrained by its highly refractory nature, poor grain boundary proton conductivity, high number of grain boundaries resulting from limited grain growth during sintering, as well as low electronic conductivity. These problems can be resolved by the fabrication of a Ni–BZY composite membrane with large BZY grains, which requires the development …

Bifurcation Type Change Of Ac Electrostatically Actuated Mems Resonators Due To Dc Bias, Dumitru Caruntu, Kyle N. Taylor

Mechanical Engineering Faculty Publications

This paper investigates the nonlinear response of microelectromechanical system (MEMS) cantilever resonator electrostatically actuated by applying a soft alternating current (AC) voltage and an even softer direct current (DC) voltage between the resonators and a parallel fixed ground plate. The AC frequency is near natural frequency. This drives the resonator into nonlinear parametric resonance. The method ofmultiple scales (MMS) is used to solve the dimensionless differential equation of motion of the resonator and find the steady-state solutions.The reduced order model (ROM) method is used to validate the results obtained using MMS. The effect of the soft DC voltage (bias) component …

Application Of Limited Mixing In The Hele–Shaw Geometry In Fabrication Of Janus Hydrogels, Md Mahmudur Rahman

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

It is widely accepted that cells behave differently responding to the stiffness of their extracellular matrix (ECM). Such observations were made by culturing cells on hydrogel substrates of tunable stiffness. However, it was recently proposed that cells may sense how strongly they are tethered to ECM, not the local stiffness of ECM. To investigate both hypotheses, we developed a method to fabricate Janus polyacrylamide (PAAM) gels. We squeeze two drops of different concentrations in the Hele-Shaw geometry to generate radial Stokes flow. When the drops coalesce, limited mixing occurs at the interface due to the narrow confinement, and diffusion normal …

Mechanical Engineering News, Georgia Southern University

Mechanical Engineering: News & Publications (2013-2023)

• Dr. Mitra of Mechanical Engineering Receives National Recognition

Semi-Annual Program Progress Performance Report For University Transportation Systems, Florida Solar Energy Center, David L. Block

FSEC Energy Research Center®

The Electric Vehicle Transportation Center's (EVTC) vision is to transform the country's transportation network into a fully integrated "smart" electric vehicle deployment system coupled with a "smart" electric grid achieved with maximum efficiency and minimum time and disruption.

To accomplish the EVTC vision, the Center's goals are to serve as the focal point for the U.S. Department of Transportation's strategic goal of planning for near-term integration of alternative fuel vehicles as a means to build a sustainable transportation system. The project will evaluate technologies, standards and policies to ensure seamless integration of EVs into a complex electricity grid and transportation …

Flow-Controlling Header, David J. Bayless, Morgan Lefay Vis-Chiasson, Gregory G. Kremer, Ben J. Stuart

Mechanical and Aerospace Engineering Faculty Research & Creative Works

An apparatus and method for holding a membrane, screen or other flexible planar body in tension, while providing a conduit for water or other liquid to flow to the membrane being held. The membrane extends from inside a manifold body that carries the liquid, and the manifold body supports the membrane at one edge while the membrane is pulled in tension. Liquid pressure builds up inside the manifold body, preferably by entering a pressure chamber at the top of the manifold body. At a feeding pressure in the pressure chamber the liquid is distributed to the membrane for microbe growth. …

3d Printing Of Stainless Steel For Engineering Applications, Michael Doyle

Undergraduate Research Symposium

3-D metal printing has the potential to solve problems in the medical, prototyping, automotive, aerospace, defense, and other engineering industries. To reach the potential of any manufacturing process, the final product’s material characteristics and how the process affects those characteristics must be understood to meet the demands of industrial applications. There is a gap in standard testing information regarding metal based 3-D metal printing processes. The purpose of this research is to fill that gap of valuable information for this manufacturing process, so that its principles can be used to design better products. Fundamental tensile and compression tests were executed …

Paint Book System Development, Dale Boynton

Undergraduate Research Symposium

Jarraff Industries has a current Paint Book System which is out of date. The current system is simply pictures of the parts and part numbers for them. It has old versions of parts in it. This creates confusion when the current parts show up and look different. Also, new pictures have to be taken every time a new part is made, which creates a delay in the process to update the books. For a solution three different samples for new Paint Books were made to distribute to users and get feedback on what they liked and did not like about …

Small Scale Wind Turbine, Cameron Allen, Davis Gumbo, Mitchell Petronek, Scott Roskens

College of Engineering Presentations

The Department of Energy (DOE) has put together a collegiate wind competition to design, build, and market a small wind turbine (17.7in diameter rotor dimension). For our mechanical engineering senior design project our team will participate in this competition. Ten schools will compete in the competition in Las Vegas this May. Our team designed a wind turbine to produce power for ultraviolet light water purification in remote areas and during emergency situations. The turbine was designed to produce 10 watts at a wind speed between 5 and 14 m/s. The turbine is also equipped with an emergency brake that will …

Stability Of N=6 Normal And Right-Angled Kaleidocycles Under The Influence Of Energy Elements, Brett Rowberry, Dr. Larry Howell

Journal of Undergraduate Research

Normal and right-angled n=6 kaleidocycles are structures composed of six tetrahedra. They are capable of continuous rotation while only requiring 240° of rotation on each joint between adjacent tetrahedra. Because of this fact, kaleidocycles may be made fully compliant with no moving parts. Having continuous rotation in a monolithic fully compliant structure is rare, if not unique. One consequence of having compliant joints is that as they are flexed from their unstrained positions, energy is stored. As the kaleidocycle is rotated, energy is stored and released from each of the joints in a complex manner. The purpose of this research …

Design Of A Robot Head For An Assistive Robot Used In The Clinical Treatment Of Children With Autism, Jacob Robinson, Dr. Mark Colton

Journal of Undergraduate Research

Autism is a spectrum disorder that is characterized by an impairment of the child’s social relationships, communication skills, and imaginative thought, resulting in a decreased quality of life for the child and his or her family, as well as significant economic costs to society. Although clinical treatment has helped some autistic children learn social skills, many others do not respond well to clinical treatment. Some research groups have investigated the use of robots as a tool to help therapists connect to the patient easier. Autistic children are more inclined to interact with a mechanical device because they exhibit repeatable actions …

An Investigation Of Methods For Actuating Robot Arms: Direct Vs. Pulley Vs. Bowden Cable Actuation Methods, Dallin Swiss, Dr. Mark Colton

Journal of Undergraduate Research

A group of BYU researchers and therapists designed a robot named “Troy” for use in studies to investigate robot-assisted therapy for children with autism [1]. Troy was considered effective and successful but studies suggest that developing a new robot with greater realism and additional capabilities may promote greater clinical benefits [2]. The next robot must be safer and enable physical interaction between the robot and child. This can be done by controlling the weight, speed and flexibility of the robot arms. In particular, reducing their weight would reduce the inertial forces put on the child when interacting with the robot

Measuring Combustion Efficiency Of Improved Cookstoves And Associated Air Quality, Whitney Steed, Erin Hamson, Jeff Lord, Dr. Matt Jones

Journal of Undergraduate Research

Statistics report that approximately three billion people in the world prepare their meals using solid fuels1. The incomplete combustion that comes from burning these solid fuels creates harmful fumes and particulate matter that damage human health. Our goal was to create standard methods to measure progress towards cleaner stove emissions, focusing on cookstoves in Peru. These consistent testing procedures will allow designers to assess the impact of design changes on cookstoves by using them to measure the combustion efficiency of biomass cookstoves and to measure the indoor air quality in homes where biomass cookstoves are used.

Direct Generation Of Smart Pareto Sets In Multiobjective Optimization, Braden Hancock, Dr. Christopher A. Mattson

Journal of Undergraduate Research

In October 2013, we proposed the development of a method to directly generate smart Pareto sets of solutions in multiobjective optimization problems. Thanks to the opportunity that we received to pursue this research through an ORCA grant, we were able to develop that technology and disseminate it in the scientific community. The results of this research include a peer-reviewed journal article, a professional conference paper, a regional student conference paper, and an Honors thesis.

Influence Of Intermediate Lamina Propria Composition On Synthetic Vocal Fold Vibration: A Comparison Of The Epi And Stiff Ligament Models, Ryan Jenkins, Dr. Scott Thomson

Journal of Undergraduate Research

The vocal folds are two multi-layered regions of tissue located in the larynx that vibrate as air flows past from the lungs. This vibration is the basis of voiced speech, one of mankind’s primary means of expression. Due to a complex fluid-structure-acoustic interaction and the inaccessibility of in vivo tissue for observation, synthetic models have been developed and used to study different aspects of the mechanics of speech production. This project compared the performance of two self-oscillating synthetic vocal fold models that differed in their composition of an internal tissue layer called the intermediate layer of the lamina propria. Until …

An Analytical Model For Heat Transfer Through A Thermoelectric Device Used In Waste Heat Recovery, Zachary Smith, Dr. Matthew Jones

Journal of Undergraduate Research

A considerable amount of energy that is produced in a typical power generation process is rejected to the environment as low-grade waste heat. This heat is rejected at a temperature that is difficult to efficiently convert into electricity. One promising method of recovering this waste heat is through the use of thermoelectric generators (TEGs) that operate by means of the Seebeck effect. Effort has previously been placed in predicting the power output of TEGs. With knowledge of the temperature differential across a thermoelectric device and the properties of the electrical components the device is connected to, the electrical power output …

Reproducing Laboratory-Scale Rip Currents On A Barred Beach By A Boussinesq Wave Model, Ke-Zhao Fang, Ji-Wei Yin, Zhi-Li Zou, Zhong-Bo Liu, Ping Dong

Journal of Marine Science and Technology–Taiwan

The pioneering work of Haller [8] on physically investigating bathymetry-controlled rip currents in the laboratory is a standard benchmark test for verifying numerical nearshore circulation models. In this paper, a numerical model based on higher-order Boussinesq equations was developed to reproduce the number of experiments involved in such an investigation, with emphasis on the effect of computational domain size on the numerical results. A set of Boussinesq equations with optimum linear properties and second-order full nonlinearity were solved using a higher-order finite difference scheme. Wave breaking, moving shoreline, bottom friction, and mixing were all treated empirically. The developed model was …

A Modelling Study Of Seawater Intrusion In The Liao Dong Bay Coastal Plain, China, Fei Ding, Takao Yamashita, Han Soo Lee, Graduate School For International Development And Cooperation, Hiroshima University, Higashi-Hiroshima, Japan Pan

Journal of Marine Science and Technology–Taiwan

To investigate the extent of seawater intrusion in the Liao Dong Bay coastal plain, China, a numerical model for variable-density groundwater flow and miscible salt transport was developed. The SEAWAT code was used to solve the density-dependent groundwater flow and solute transport governing equations. The simulation was conducted for 55 months from October, 2004 to April, 2009. The numerical model was calibrated by the hydraulic heads measured in April, 2009. Using the calibrated model and the same hydrogeological conditions in 2004, the extent of seawater intrusion prediction was conducted for the next 40 years. The results show that the extent …

Experimental Study Of Characteristics Of Motions Of A Large Mooring Ship In Long-Period Waves, Xian-Ying Shi, Ning-Chuan Zhang, Chang-Ping Chen, Heng-Zhi Jiang, Lei Cui

Journal of Marine Science and Technology–Taiwan

By using the method of physical model tests, the characteristics of mooring ship’s motion responses in transverse long-period waves have been studied under different conditions, including such elements as loading conditions, wave heights, and specific patterns of mooring, etc. The results indicate that: the mooring ship’s movements of surge, sway and yaw had their own natural periods; the movement of sway was a period motion. The ratio of the natural period of sway and the natural rolling period of the mooring ship was within 1.11~1.23. The peak value of sway grew along with the increase of the wave period; the …

Subtalar Fusion Fixture Design And Test, Nathan Ortiz

Honors Theses

Subtalar arthrodesis is performed when cartilage in the talo-calcaneal (the ankle) joint is degraded in a patient and there are multiple approaches to this surgery. Using synthetic bone material, fixtures were cast from aluminum, using the process of evaporation pattern casting, and epoxy. This casting was used to grip the calcaneus bone of the foot in order to load it mechanically, simulating different scenarios that would be encountered during walking. The relative displacement of the ankle joint was measured using a digital image correlation (DIC) program that was modified to work in both two- and three-dimensional space. This program can …