Mechanical Engineering Commons^™

A Coupled Source Panel, Actuator Line, And Viscous Vortex Particle Method In An O(N) Scheme, Ryan Anderson, Andrew Ning

Faculty Publications

Wake interactions play a significant role in aerodynamics. However, common modeling approaches are either expensive or lack fidelity, making them unreliable or difficult to use in the design process. The vortex particle method can capture the relevant physics effectively, but imposing boundary conditions with solid surfaces in a computationally efficient way is challenging. We explore two possible methods of imposing solid surface boundary conditions of vortex particle simulations. The first, a novel variation on a pure particle approach, is easy to implement but is moderately expensive, and suffers from some numerical instability. The second, source panels accelerated with a fast …

Retention Forces For Drops On Microstructured Superhydrophobic Surfaces, Shaur Humayun, R. Daniel Maynes, Julie Crockett, Brian D. Iverson

Faculty Publications

Accurate models of retention forces between drops and superhydrophobic (SH) surfaces are required to predict drop dynamics on the surface. This retention force is, in turn, useful in modeling heat transfer rates for dropwise condensation on a SH surface. Drop contact angle distribution and base area on SH surfaces are essential factors for predicting retention forces. The present work measures the contact angle distribution and base area shapes of various drop sizes over a wide range of solid fraction for inclined microstructured SH surfaces at the point of drop departure. Base area shape was found to be well approximated using …

Meshless Large Eddy Simulation Of Propeller-Wing Interactions With Reformulated Vortex Particle Method, Eduardo Alvarez, Andrew Ning

Faculty Publications

The vortex particle method (VPM) has gained popularity in recent years due to a growing need to predict complex aerodynamic interactions during preliminary design of electric multirotor aircraft. However, VPM is known to be numerically unstable when vortical structures break down close to the turbulent regime. In recent work, the VPM has been reformulated as a large eddy simulation (LES) in a scheme that is both meshless and numerically stable, without increasing its computational cost. In this study, we build upon this meshless LES scheme to create a solver for interactional aerodynamics. Rotor blades are introduced through an actuator line …

Reliability Study Of A New Electromechanical Device Designed To Measure The Relative Dorsal Mobility Of The First Ray Of The Foot, Philippe Passeraub

Faculty Publications

Introduction: A new electromechanical instrument has been developed to measure relative dorsal mobility of the first ray in an objective and reliable way by simulating ground reaction forces during gait. This device equally applies a standardized, electronically controlled, and precise force under the first metatarsal head M1 as well as under the heads of the lesser metatarsals M2 to M5. The relative dorsal mobility between these two bearings is then measured. The purpose of this study is to assess the intra- and inter-examiners reliabilities of the measurements obtained with this device. Methods: The protocol included two examiners and 36 feet …

Reliable Mode Tracking For Gradient-Based Optimization With Dynamic Stability Constraints, Taylor Mcdonnell, Andrew Ning

Faculty Publications

In order to construct mode-specific flutter constraints for use in gradient-based multidisciplinary design optimization frameworks, mode tracking must be used to associate the current iteration's modes with the modes corresponding to each constraint function. Existing mode tracking methods, however, do not provide a method by which to ensure the accuracy of mode associations, making them unsuitable for use in situations where obtaining correct mode associations is critical. To remedy this issue, a new mode tracking method is presented which incorporates backtracking logic in order to maintain an arbitrarily high degree of confidence in mode correlations during gradient-based optimization and/or during …

Impact Of Zirconia Slurry In Steel Powder On Melt Pool Characteristics In Laser Powder Bed Fusion, Taylor Davis, Tracy W. Nelson, Nathan B. Crane

Faculty Publications

Purpose – dding dopants to a powder bed could be a cost-effective method for spatially varying the material properties in laser powder bed fusion (LPBF) or for evaluating new materials and processing relationships. However, these additions may impact the selection of processing parameters. Furthermore, these impacts may be different when depositing nanoparticles into the powder bed than when the same composition is incorporated into the powder particles as by ball milling of powders or mixing similarly sized powders. This study aims to measure the changes in the single bead characteristics with laser power, laser scan speed, laser spot size and …

Experimentally Measured Lumbar Skin Strains During Activities Of Daily Living, Andrew Gibbons, Paul Mcmullin, Darian Emmett, Ulrike H. Mitchell, David T. Fullwood, Anton E. Bowden

Student Works

Introduction: When mechanical stimulation of the skin, post-surgery, is kept at a minimum, the risk for hypertrophic scarring is reduced. Therefore, surgeons have utilized different tools for optimal scar outcomes such as cutting along or perpendicular to the Langers lines or collagen fiber orientation^1,2. However, biomechanical strains induced in the skin during activities of daily living (ADL) are the primary mechanism for suture opening, and increased awareness of these strains may provide informative insights to both pre-operative incision planning, as well as post-operative counseling with the patient regarding specific activities that may lead to wound re-opening.

Methods: Data …

Tactics Ideation Experiment Data, Thomas L. Ashworth, Carl D. Sorensen

ScholarsArchive Data

This data includes the template worksheets, as well as filled worksheets that include ideas written by the participants in a research experiment. This experiment tested the effectiveness of a novel tactics ideation method (i.e., Random Prompts method) to a modified Brainwriting method. Transcribed copies of this data are also included.

Accompanying the data are experiment briefing presentations, Python code for rapid evaluation of the data (the evaluation methods themselves were also developed by the authors), a spreadsheet file with evaluation data (this is a necessary input to the code), and organizational trees (for team idea sets) associated with the evaluation …

Effects Of Rotor-Airframe Interaction On The Aeromechanics And Wake Of A Quadcopter In Forward Flight, Denis-Gabriel Caprace, Andrew Ning, Philippe Chatelain, Grégoire Winckelmans

Faculty Publications

From small drones to large Urban Air Mobility vehicles, the market of vertical take-off and landing (VTOL) aircraft is currently booming. Modern VTOL designs feature a variety of configurations involving rotors, lifting surfaces and bluff bodies. The resulting aerodynamics are highly impacted by the interactions between those components and their wakes. This has consequences on the aircraft performance and on the downstream wake. Studying the effects of those interactions through CFD can inform the development of cheaper numerical models. In this work, we focus on the interaction between rotors and bluff bodies based on the example of a generic quadcopter …

Optimizing Build Plate Adhesion Of Polymers In Fused Granule Fabrication Processes, Alex Schroeder, Jason Weaver

Faculty Publications

Perhaps the most crucial element of fused granule fabrication (FGF) is material adhesion; in order to achieve a successful product, the material being printed must adhere to the build plate. For optimal products, the material should only adhere to the build plate until the print is complete, then be easily removable. This paper examines the effects of different build plates, environments, and bonding agents on material adhesion during the FGF process in a CNC mill machine. The force to remove polycarbonate (PC) and polypropylene (PP) from build plates was tested with various bonding agents. Except in one case, the adhesive …

A Comparison Of Layer Deposition And Open Molding Of Petg By Fused Pellet Fabrication In An Additive Manufacturing System, Alex Gibson, Jason Weaver

Faculty Publications

Additive manufacturing continues to offer new possibilities in both production and economics. The industry has quickly adopted it to rapidly produce parts that would be difficult or cost preventative otherwise. Recent innovation has expanded its capabilities, however there are still significant limitations. Most AM processes are restricted by materials available, in producing large parts, or by not achieving material deposition speeds to make certain products feasible. In addition, tight tolerances for features and surfaces cannot be produced without substantial post processing. High-speed Fused Pellet Fabrication (FPF) in combination with Hybrid Manufacturing (HM) offers expanded capabilities as additive and subtractive process …

Trade-Off Characterization Between Social And Environmental Impacts Using Agent-Based Models And Life-Cycle Assessment, Joseph C. Leichty, Christopher S. Mabey, Christopher A. Mattson, John L. Salmon, Jason Weaver

Faculty Publications

Meeting the UN’s sustainable development goals requires designers and engineers to solve multi-objective optimization problems involving trade-offs between social, environmental, and economic impacts. This paper presents an approach for designers and engineers to quantify the social and environmental impacts of a product at a population-level and then perform a trade-off analysis between those impacts. In the approach, designers and engineers define the attributes of the product as well as the materials and processes used in the product’s life cycle. Agent-Based Modeling (ABM) tools that have been developed to model the social impacts of products are combined with Life- Cycle Assessment …

Mechanical Actuation Via Resorbable Materials, Bethany Parkinson

Undergraduate Honors Theses

Resorbable materials—or materials which diffuse into their surroundings—present a promising means of actuating mechanical systems. In current practice, such as in the realm of in vivo surgical devices, resorbable materials are often intended to perform a temporary function and completely dissolve when that function is completed (e.g. resorbable sutures). In this paper, resorbable materials are proposed for use in a different way: as a means for actuating mechanical systems. We create several prototypes which demonstrate that resorbable materials, combined with stored energy, can be used to actuate mechanical systems under several loading conditions and in various applications. We also present …

Optimization Of Solar-Coal Hybridization For Low Solar Augmentation, Aaron T. Bame, Joseph Furner, Ian Hoag, Kasra Mohammadi, Kody Powell, Brian D. Iverson

Faculty Publications

This work presents a process to determine the preliminary optimal configuration of a concentrating solar power-coal hybrid power plant with low solar augmentation, and is demonstrated on a regenerative steam Rankine cycle coal power plant in Castle Dale, UT, USA (average DNI of 542 W m⁻²). A representative plant model is developed and validated against published data for a coal power plant. The simplifications that lead to the representative model from a coal power plant model include combining multiple feedwater heaters, combining turbines, and using a mass-average calculation for extraction steam properties. Comparing net power generation and boiler …

Flowunsteady: An Interactional Aerodynamics Solver For Multirotor Aircraft And Wind Energy, Eduardo Alvarez, Judd Mehr, Andrew Ning

Faculty Publications

The ability to accurately and rapidly assess unsteady interactional aerodynamics is a shortcoming and bottleneck in the design of various next-generation aerospace systems: from electric vertical takeoff and landing (eVTOL) aircraft to airborne wind energy (AWE) and wind farms. In this study, we present a meshless CFD framework based on the reformulated vortex particle method (rVPM) for the analysis of complex interactional aerodynamics. The rVPM is a large eddy simulation (LES) solving the Navier-Stokes equations in their vorticity form. It uses a meshless Lagrangian scheme, which not only avoids the hurdles of mesh generation, but it also conserves the vortical …

Large Eddy Simulation Of The Wakes Of Three Urban Air Mobility Vehicles, Denis-Gabriel Caprace, Andrew Ning

Faculty Publications

Recent advances in urban air mobility have driven the development of many new VTOL concepts. These vehicles often feature original designs and futuristic shapes. Due to their novelty, the wake characteristics of such aircraft are unknown. However, large wake-induced velocities, should they exist, may be dangerous for any other vehicle evolving in their close proximity. Therefore, improved knowledge about the wakes of VTOL vehicles is needed to guarantee the safety of urban air mobility operations. In this work, we study the wake of three VTOL aircraft in cruise by means of large eddy simulation. We present a two-stage numerical procedure …

Low-Cost Prosthetic Feet For Underserved Populations: A Comparison Of Gait Analysis And Mechanical Stiffness, Kaleigh Renninger, Brevin Banks, Dustin A. Bruening

Library/Life Sciences Undergraduate Poster Competition 2022

• Lower limb loss is an ongoing cause of disability throughout the world.
• Despite advancements in prosthetic technologies, there are numerous underserved populations in need of effective low-cost prosthetic foot options.

Kemar Hats Head Orientation Directivity, Samuel D. Bellows, Timothy W. Leishman

Directivity

This directivity data set for a KEMAR head head-and-torso simulator (HATS) includes head orientations in 14 directions in 5° steps starting from 0° to 40° and then in 10° steps from 40° to 90°. The full spherical measurements followed at an a = 0.97 m radius with the mouth aperture at the spherical center. The sampling density and distribution followed the AES 5° dual-equiangular sampling standard, omitting the south pole (θ = 180°). Thus, each spherical directivity assessment included 36 polar-angle θ samples and 72 azimuthal-angle ϕ samples. The presented data include 22 1/3-octave bands, ranging from 80 Hz …

Modeling Data And Reactor Data Associated With The Design, Modeling, And Testing Of The Pressurized Oxy-Coal (Poc) Reactor, Bradley R. Adams, Andrew R. Fry, Dale R. Tree

ScholarsArchive Data

Data files in the zipped folders below contain research and development information related to the design, modeling, construction and testing of a pressurized, dry feed, oxy-coal reactor at Brigham Young University between 2016 and 2021. The reactor is a once-through system that includes a pressurized dry-coal feed system, a slagging combustion reactor, a spray quench and tube and shell heat exchanger for gas cooling, a cyclone particle collector, and gas depressurization and dilution system. The system is operated with an OPTO22 control system and includes instrumentation to measure gas and wall temperature profiles, radiative heat flux profiles (indicative of flame …

A General Coupling Methodology For Unsteady Aerostructural Optimization With Analytic Derivatives, Taylor Mcdonnell, Adam Cardoza, Denis-Gabriel Caprace, Andrew Ning

Faculty Publications

Multidisciplinary design optimization offers a comprehensive approach for designing complex aerostructural systems such as wind turbines. Gradient-based multidisciplinary design optimization can be used to optimize complex systems using large numbers of design variables. However, the convergence of gradient-based optimization methods to an optimal solution is highly dependent on the accuracy of the provided derivatives. In this paper, we propose a general method for creating unsteady coupled systems for steady-state, eigenvalue, and time-domain analyses. We then describe how highly accurate derivatives may be obtained from these analyses using a combination of automatic differentiation and analytic methods (including the unsteady adjoint). Finally, …

Closed Loop Recycling Of Low Friction Polymers In Fused Granule Fabrication Additive Manufacturing Processes, Neil Thompson, Jason Weaver

Faculty Publications

Plastic waste is a critical worldwide problem that impacts additive manufacturing (AM). Extensive research has explored how plastic waste in AM can be reduced by recycling prints into new filament, with varying success. An alternative to filament-based extrusion is “fused granule fabrication” (FGF), which extrudes from pellets or granules. This method is often used for large area additive manufacturing (LAAM) of polymers. This paper expands upon the knowledge base from previous research on LAAM and examines the extent to which PETG can be recycled and reprinted through the same FGF tool without significant loss to its material properties. The metric …

Durability Of Vacuum Infusion Tooling Produced From Fused Granular Fabrication Additive Manufacturing, Nathan Northrup, Jason Weaver, Andy R. George

Faculty Publications

Large area additive manufacturing (LAAM) has the capability to create tooling that is lower cost than conventionally manufactured tooling and still has sufficient properties for many applications. A vacuum infusion mold was printed from fiberglass-ABS and evaluated for wear and suitability for small vacuum infusion runs. The mold was designed to accentuate high wear as a “worst case” scenario. The mold was able to produce 10 parts successfully before any noticeable change occurred to the surface finish. By 14 parts, the surface finish had roughened sufficiently that demolding was difficult and resulted in damage to the part. Profilometry measurements showed …

Incorporating High-Fidelity Aerostructural Analyses In Wind Turbine Rotor Optimization, Denis-Gabriel Caprace, Adam Cardoza, Andrew Ning, Marco Mangano, Sicheng He, Joaquim R. R. A. Martins

Faculty Publications

s demand grows for wind turbines with larger blades, the design of future wind turbines must account for multi-physical interactions and an ever-increasing number of design load conditions. One aspect, aerostructural coupling, calls for design tools that are both accurate and computationally efficient. In this paper, we present a combined-fidelity approach that couples high-fidelity computational fluid dynamics and computational solid mechanics simulations, with a conventional aeroelastic turbine modeling tool based on blade element momentum and beam theories. The approach is integrated into a multidisciplinary optimization framework. It takes advantage of the high-fidelity tightly-coupled aerostructural simulations to evaluate the rotor power …

Considering Thickness-Accommodation, Nesting, Grounding And Deployment In Design Of Miura-Ori Based Space Arrays, Terri Bateman, Diana Bolanos, Nathan Brown, Brooklyn Clark, Larry L. Howell, Collin Ynchausti, Hunter Pruett, Jared Hunter, Spencer P. Magleby

Faculty Publications

The Miura-ori pattern exhibits favorable qualities desirable for deployable space arrays – especially achieving a large deployed area from a compact stowed volume. However, implementing the Miura-ori into a finite-thickness, engineered system poses challenges that are not manifest in a zero-thickness model. As such, it is important to understand and address the limitations of the pattern before implementing it into an engineered system. This paper presents the Miura-ori as a favorable, yet challenging, pattern in design of deployable space arrays. Challenges including thickness-accommodation, nesting, grounding and deployment are presented to introduce designers to unapparent complications associated with design of Miura-ori …

System Identification Of Postural Tremor In Wrist Flexion-Extension And Radial-Ulnar Deviation, Sydney Bryanna Ward

Theses and Dissertations

Generic simulations of tremor propagation through the upper limb have been achieved using a previously developed postural tremor model, but this model had not yet been compared with experimental data or utilized for subject-specific studies. This work addressed these two issues, which are important for optimizing peripheral tremor suppression techniques. For tractability, we focused on a subsystem of the upper limb: the isolated wrist, including the four prime wrist muscles (extensor carpi ulnaris, flexor carpi ulnaris, extensor carpi radialis, and flexor carpi radialis) and the two degrees of freedom of the wrist (flexion-extension and radial-ulnar deviation). Muscle excitation and joint …

A High-Pressure Shear Testing Approach To Measure Flow Stresses Near A Friction Stir Welding Tool, David Prymak, Michael Miles, Tracy W. Nelson, Fredrick Michael

Faculty Publications

A new approach for measuring flow stresses near a spinning friction stir welding (FSW) tool is evaluated on AA 6061-T6 plate. The test consists of plunging a cylindrical tool with a flat face into the plate at different rotational speeds, using a variety of constant vertical loads. A viscosity-based model of the shear layer created under the tool is employed to estimate local flow stresses. The flow stresses measured by this approach exhibited an inverse relationship with temperature and a positive dependence on the pressure imposed by the spinning flat-faced tool. Compared to hot compression and hot torsion results, estimated …

Correlation Of Segmental Lumbar Kinematics With A Wearable Skin Strain Sensor Array, Andrew Gibbons, Paul Mcmullin, Joseph Peterson, Spencer Baker, Kelly Clingo, Ulrike H. Mitchell, David T. Fullwood, Anton E. Bowden

Student Works

Introduction: Joint kinematics have been shown to be strongly diagnostic of underlying pathology in the knee, hip, shoulder, and ankle. However, the anatomical complexity of the spine has made obtaining accurate, segmental kinematics extremely challenging. Current approaches required specialized hardware (e.g., a dual x-ray system), or are highly invasive (e.g., bone pins implanted into the vertebrae). Recently, our lab has developed a wearable array of skin-mounted strain sensors that hopes to address this challenge. The purpose of the present work study was to quantify the utility of this array through comparison with real-time lumbar vertebral kinematics.

Materials and Methods: A …

Development Of An Origami Inspired Composite Deployable Structure Utilizing Compliant Joints As Surrogate Folds, Samuel Porter Smith

Theses and Dissertations

This work presents the design and construction of a self-deployable, self-stiffening,and retractable (SDSR) space array from carbon fiber reinforced polymers (CFRP’s) and a working prototype is demonstrated. The effort required developing principles for the design of high-strain composite flexural joints and their integration into angled composite panels. Designing LET arrays in angled panels is explored. Analysis of simple composite LET joints is presented for two degrees of freedom. Validation of the composite LET modeling is sought through numerical methods and empirical testing. Testing of several composite LET joint specimens is conducted and the results are reported. Results indicate that (while …

Characterizing Behaviors And Functions Of Joints For Design Of Origami-Based Mechanical Systems, Nathan Chandler Brown

Theses and Dissertations

This thesis addresses a number of challenges designers face when designing deployable origami-based arrays, specifically joint selection, design, and placement within an array. In deployable systems, the selection and arrangement of joint types is key to how the system functions. The kinematics and performance of an array is directly affected by joint performance. This work develops joint metrics which are then used to compare joint performances, constructing a tool designers can use when selecting joints for an origami array. While often a single type of joint is used throughout an array, this work shows how using multiple types of joints …

Vacuum Infusion Of Composites: Durability Of Hybrid Large Area Additive Tooling For Vacuum Infusion Of Composites, Nathan Northrup, Jason Weaver, Andy R. George

Faculty Publications

The durability of a hybrid large area additively manufactured fiberglass ABS mold for vacuum infusion of composites was evaluated. The validation was done by designing and fabricating a mold for a custom test artifact and analyzing the surface geometry over the course of multiple infusions until tool failure. After printing and machining, the mold required a sealer to maintain vacuum integrity. The mold was able to produce 10 parts successfully before the sealed tool surface began to tangibly roughen, resulting in increased difficulty of demolding and a rougher surface finish. After the 14th infusion, the part required destructive force to …