Mechanical Engineering Commons^™

Rigidly Foldable Origami Twists, Thomas A. Evans, Robert J. Lang, Spencer P. Magleby, Larry L. Howell

Faculty Publications

Rigid foldability is an important characteristic of origami structures that becomes significant with non-paper materials. A rigidly foldable origami tessellation is one where the sectors remain rigid and all deflection occurs at the crease lines. Many rigidly foldable patterns have only one degree of freedom, making them potentially useful for deployable structures. Methods have been developed to construct rigidly foldable origami tessellations using materials with finite thickness based on zero-thickness rigidly foldable patterns. [Tachi 11].

Origami methods have been considered for application in deployable structures such as solar panels [Miura 85] [Zirbel et al. 13] and sterile shrouds [Francis et …

Thick Rigidly Foldable Structures Realized By An Offset Panel Technique, Bryce Edmondson, Robert J. Lang, Michael R. Morgan, Spencer P. Magleby, Larry L. Howell

Faculty Publications

Rigid-panel origami is often mathematically modeled with idealized zero-thickness panels. When paper is used to realize an origami design, the zero-thickness models are a good approximation. However, many origami-inspired designs require the use of thicker materials that likely will not behave as the zero-thickness kinematic models predict.

The offset panel technique defined previously by the authors [Edmondson et al. 14] maintains the kinematics of a zero-thickness origami source model over its full range of motion. The offset panel technique accommodates uniform and varying panel thickness as well as offset panels or gaps between panels. The preserved kinematic behavior allows designers …

Development And Validation Of A New Blade Element Momentum Skewed-Wake Model Within Aerodyn, Andrew Ning, Greg Hayman, Rick Damiani, Jason Jonkman

Faculty Publications

Blade element momentum methods, though conceptually simple, are highly useful for analyzing wind turbines aerodynamics and are widely used in many design and analysis applications. A new version of AeroDyn is being developed to take advantage of new robust solution methodologies, conform to a new modularization framework for National Renewable Energy Laboratory’s FAST, utilize advanced skewed-wake analysis methods, fix limitations with previous implementations, and to enable modeling of highly flexible and nonstraight blades. This paper reviews blade element momentum theory and several of the options available for analyzing skewed inflow. AeroDyn implementation details are described for the benefit of users …

An Experimental Study Of Subcooled Flow Boiling At Elevated Pressure In An Annular Flow Channel, Pervej Rahman

Dissertations and Theses

An experimental setup was developed to study the region of subcooled flow boiling. Multiple studies were carried out to investigate the effects of liquid velocity, pressure, and temperature on the boiling heat transfer of subcooled fluid flowing through a heated annular channel. Water was used as the working fluid and principle of Ohmic heating was used to raise water temperature. The system pressure, heat flux, & mass flux ranged from 101 to 912 kPa, 19 to 155 kW/m2, and 83 to 332 kg/m2-s, respectively. This report contains boiling curves, heat transfer coefficients of various studies and a description of the …

Freeform Extrusion Fabrication Of Titanium Fiber Reinforced 13-93 Bioactive Glass Scaffolds, Albin Thomas

Masters Theses

"Although implants made with bioactive glass have shown promising results for bone repair, their application in repairing load-bearing long bones is limited due to their poor mechanical properties as compared to human bones. This thesis study is on freeform extrusion fabrication of silicate based 13-93 bioactive glass scaffolds reinforced with titanium fibers. A composite paste was prepared with 13-93 bioactive glass filled with titanium fibers (~16 µm in diameter and aspect ratio of ~250) having 0.1 to 0.4 vol. % of the bioactive glass scaffold. This paste was then filled into a syringe manually, and then extruded through a nozzle …

Generation And Validation Of Optimal Topologies For Solid Freeform Fabrication, Purnajyoti Bhaumik

Masters Theses

"The study of fabricating topologically optimized parts is presented hereafter. The mapping of topology optimization results for Standard Tessellation Language (STL) writing would enable the solid freeform fabrication of lightweight mechanisms. Aerospace leaders such as NASA, Boeing, Airbus, European Aeronautic Defense And Space Company (EADS), and GE Aero invest in topology optimization research for the production of lightweight materials. Certain concepts such as microstructural homogenization, discretization, and mapping are reviewed and presented in the context of topology optimization. Future biomedical applications of solid freeform fabrication such as organ printing stand to save millions of lives through the robust development of …

A Novel In Situ Microscope For Studying Benthic Organisms, Andrew Mullen

Link Foundation Ocean Engineering and Instrumentation Fellowship Reports

Coastal marine ecosystems such as coral reefs, kelp forests, sea grass beds and mangroves have significant societal value. As economic resources they support tourism, fisheries and storm protection while ecologically they host high biological diversity and productivity. Many basic biological, chemical, and physical processes taking place in these marine ecosystems occur at ‘micro-­‐scales’ less than a millimeter in size. Examples of significant micro-­‐scale activities include: coral bleaching of their single-­‐ celled symbiotic algae, larval settlement and attachment, competition between sessile organisms along thin interfaces, and fluxes of particles to and from the seafloor. It is also important to consider that …

A Comparison Between Graphene And Ws2 As Solid Lubricant Additives To Aluminum For Automobile Applications, Sara Rengifo

FIU Electronic Theses and Dissertations

The purpose of this thesis was to compare graphene nanoplatelets (GNP) and WS₂ as solid lubricant additives to aluminum in order to reduce friction and wear. The central hypothesis of this work relied on lubricating properties of 2D materials, which consist layers that slip under a shear force.

Two aluminum composites were made (Al-2 vol.% GNP and Al-2 vol.% WS₂) by spark plasma sintering. Tribological properties were evaluated by ball-on-disk wear tests at room temperature (RT) and 200^°C.

WS₂ not only presented the lowest COF (0.66) but also improved the wear resistance of aluminum …

Applications Of Ultrasonic Non-Destructive Testing In 3d Printing, Parker Lawley

The Journal of Undergraduate Research

To determine the capabilities of ultrasonic non-destructive testing methods in 3D printing, test specimens were designed to evaluate advantages and limitations in using ultrasoundC-scanning to determine 3D printing effectiveness. A Matlab program was written to process the data obtained from the UTwin software and ultrasound tank, as well as produce 3D models of the parts being tested. Thickness, types of features, and various printing methods were evaluated to determine how these characteristics vary in effectiveness of C-scan imaging. Results from the UTwin software C-scans were compared to the Matlab program’s imaging and three-dimensional modeling. After determining the capabilities of ultrasonic …

La0.6Sr1.4Mno4+Δ Layered Perovskite Oxide: Enhanced Catalytic Activity For The Oxygen Reduction Reaction, Yarong Wang, Zhibin Yang, Fanliang Liu, Chao Jin, Jiao Wu, Ming Shen, Ruizhi Yang, Fanglin Chen

Faculty Publications

Efficient electrocatalysts for the oxygen reduction reaction (ORR) is a critical factor to influence the performance of lithium–oxygen batteries. In this study, La_0.6Sr_1.4MnO_4+δ layered perovskite oxide as a highly active electrocatalyst for the ORR has been prepared, and a carbon-coating layer with thickness <5 nm has been successfully introduced to enhance the electronic conductivity of the as-prepared oxide. XRD, XPS, Raman, SEM and TEM measurements were carried out to characterize the crystalline structure and morphology of these samples. Rotating ring-disk electrode (RRDE) technique has been used to study catalytic activities of the as-prepared catalysts for the ORR in 0.1 M KOH media. RRDE results reveal that carbon-coated La_0.6Sr_1.4MnO_4+δ exhibits better catalytic activity for the ORR. For the carbon-coated La_0.6Sr_1.4MnO_4+δ, the ORR proceeds predominately via a direct four electron process, and a maximum cathodic current density of 6.70 mA cm⁻² at 2500 rpm has been obtained, …

Quantification Of The Effect Of Tool Geometric Features On Aspects Of Friction Stir Welding, Md. Reza-E-Rabby

Theses and Dissertations

In the friction stir welding (FSW) process, tool stirring and synchronized movement of the weld materials along a pre-existing seam line causes thermal gradients and severe plastic deformation resulting in the bonding of the adjacent materials. For a given set of welding parameters, tool pin geometries (dimensions, shape) and vertical/helical features that dictate the material motion also have significant effects on process response variables during FSW. Among the primary process controlling parameters in FSW, tool pin geometry and feature vary multifariously in terms of shape, dimensions, feature insertion technique depending on the weld material and application of joint. The current …

Design Of Experiments Analysis Of Non-Standard Inputs For The Optimization Of Friction Stir Welding, Ryan Widejko

Theses and Dissertations

The purpose of this study was to use non-standard Design of Experiments (DoE) inputs in Friction Stir Welding (FSW) to deduce relationships between various weld input and response variables. Typically, inputs for FSW DoE are tool rotational speed, welding speed and forge force. In this study, three different input factors were investigated: travel speed, thermal boundary conditions (TBC), and advance per revolution (APR). The experimental design included a full factorial with each factor at two levels plus two centerpoint runs. Response variables included weld temperature, microstructure, hardness, power, weld energy, and in plane forces.

An investigation of the effect of …

A Study To Evaluate Non-Uniform Phase Maps In Shape Memory Alloys Using Finite Element Method, Naren Motte

Theses and Dissertations

The unique thermo-mechanical behavior of Shape Memory Alloys (SMAs), such as their ability to recover the original shape upon heating or being able to tolerate large deformations without undergoing plastic transformations, makes them a good choice for actuators.

This work studies their application in the aerospace and defense industries where SMA components can serve as release mechanisms for gates of enclosures that have to be deployed remotely. This work provides a novel approach in evaluating the stress and heat induced change of phase in a SMA, in terms of the transformation strain tensor. In particular, the FEA tool

ANSYS has …

Binder Jet Additive Manufacturing Of Stainless Steel-Hydroxyapatite Bio-Composite, Don Suranga Dhanushka Uduwage

All Graduate Theses, Dissertations, and Other Capstone Projects

This study was conducted to create a bio-composite with a porous structure using the binder-jet printing additive manufacturing process. The samples were printed by changing the parameters such as layer thickness, roller speed, sintering time and sintering temperature of the X1-Lab binder jet additive manufacturing printer. The samples were printed 80% stainless steel 316 mixed with 20% Calcium Phosphate Tribasic by volume. Eight experiments were attempted to print according to the fractional factorial design of experiment. The effects of changing parameters on the mechanical properties of the new bio-composite was tested using ASTM E-09 compressive strength standards. The compression testing …

Derivation And Validation Of The Friction, Gravitational, And Air Forces Encountered During Installation Of Fiber Optic Cable, Faheed Olayemi Owokoniran

All Graduate Theses, Dissertations, and Other Capstone Projects

This paper presents an introduction to fiber optic cable and the fiber optic communication system. An important phase in the supply of this new technology is to transport the fiber optic cable to the vicinity of service. Cable pulling and cable blowing - laminar flow; piston type - are the two main methods of installing fiber optic cable. Both methods of installation have limiting factors that need to be evaluated in order to perform a successful installation. The limiting factors for laminar type cable blowing are further discussed in this paper. A method was proposed to determine the forces - …

Air Flow And Rain Water Penetration Analysis On Generator Enclosures Using Cfd Simulations, Sasanka Andawatta Kankanamge

All Graduate Theses, Dissertations, and Other Capstone Projects

Rain water penetration testing on power generator units requires a number of complicated procedures, requiring many resources. As such, a Computational Fluid Dynamics (CFD) tool, "FloEFD for Creo" is used to study the water penetration behavior on a OM924 diesel power generator enclosure in a computational environment. First, the three governing equations in fluid dynamics are derived and explained using simple methods. Next, behavior of rain water droplets upon impact is briefly discussed. Air velocity, volumetric flow rate and static pressure drop were measured physically in the OM924 generator enclosure. Then, a CFD model for the OM924 enclosure was developed …

We All Go Home! The Evolution Of Firefighter Accountability Systems, Jeremy Roy

Honors Theses

Accountability is arguably the single most important tool that a fire department has at its disposal. Although accountability systems have been used throughout history, one thing is proven: when there is no accountability system in place, it is only a matter of time before firefighters will get injured, or worse, lose their lives. This work will discuss the history of fire department methodology dealing with the creation of incident management accountability systems. In order to provide historical evidence that lack of an accountability system can cause injury or death, case studies of multiple fire departments that have reported line of …

Creation Of A Portable, 3d-Printable, Iphone-Compatible Spectrophotometer, Elise K. Grasse

Williams Honors College, Honors Research Projects

Spectroscopy is a widely used chemical and medical analysis tool. While spectrophotometers are commonly found in many universities and laboratories, they are not available to all high schools or laboratories in developing countries. The objective of this project was to design a high-quality, 3D-printable, iPhone-compatible spectrophotometer that uses a cell phone camera and interface to collect data. The created 3D-print file will be available to anyone with access to a 3D printer which are increasingly found in many laboratories and schools across the country. A low cost pre-printed kit will also be made for those without access to a 3D …

2015 Afrl University And Service Academy Design Challenge, Andrew P. Killmeyer, Jacob Stein, Casey Hale, Jeff Quartermaine, Kevin Rolik, Brandon Null, Nick Tsangeos, Marissa Seeley, Sam Moats, Nicholas Garafolo Phd, Daniel Slattery

Williams Honors College, Honors Research Projects

The University of Akron’s Air Force Research Laboratory’s Design Challenge Team has engineered a Heat Stress Prevention Kit that includes a facial mask in which the soldier will cool down from the inside out by breathing in the cool air circulating throughout the mask. This cool air is produced from a thermoelectric chip, which has a specific temperature difference on either side, one hot and one cold. Each of the sides are isolated from one another and with the combination of heatsinks, fans, and the simple process of breathing, a system is created by inhaling cool air. The entire system …

Design Of The University Of Akron's 2015 Fsae Electric Vehicle Braking System, Nicholas D. Galbincea

Williams Honors College, Honors Research Projects

The following report encompasses the design of the 2015 University of Akron’s FSAE formula electric braking system. The system is one based on hydraulic braking and designed for a one man performance racing vehicle. The objective of the system is to convert the kinetic energy of the vehicle into thermal energy, allowing the vehicle to decelerate optimally and safely. The design includes three major categories: calculation and evaluation of the hydraulic system in order to select calipers and master cylinders, the design of the pedal box, and the design of the rotors.

The results and findings of the proceeding report …