Acoustics, Dynamics, and Controls Commons^™

Automated Control System For The Remote-Controlled Torch Positioner, Christopher Ferguson, Anna Abate, Kyle Cramer, Alex Sabitsch, Jacob Stefanko

Williams Honors College, Honors Research Projects

The goal of this project is to design and implement a controls system for Dr. Morscher’s burner rig. The rig serves to simulate jet turbine conditions and test how materials, specifically ceramic matrix composites, react under high temperatures and stresses. Currently, the location of the torch relies solely on manual adjustments and has no automated control system. The improved design will automatically adjust the torch position based on the desired temperature of the sample being tested, therefore maintaining a steady environment for the sample. The current method of manual adjustments for regulating temperature is a crude solution that does not …

Mise Au Point D’Une Méthode De Mesure Objective De L’Effet D’Occlusion Basée Sur La Voix, Hugues Nélisse, Hugo Saint-Gaudens, Franck Sgard, Olivier Doutres

Rapports de recherche scientifique

Lors de l’utilisation de protecteurs auditifs ou de prothèses auditives, le fait d’obstruer le canal auditif peut engendrer un effet indésirable et désagréable, appelé « effet d’occlusion », qui se manifeste notamment par la sensation que notre propre voix sonne différemment, avec de basses fréquences amplifiées, qu’elle est distordue. L’effet d’occlusion est souvent considéré comme une source d’inconfort qui entraîne parfois les utilisateurs de protecteurs ou de prothèses à mal les utiliser ou encore à simplement les retirer. Dans le cas des travailleurs, par exemple, le retrait des protecteurs auditifs peut les exposer à des niveaux de bruits potentiellement dangereux, …

Base Vibration Effects On Additive Manufactured Part Quality: A Study Of 3d Printing Onboard U.S. Navy Ships, Nick Jensen

Dissertations, Master's Theses and Master's Reports

The current landscape of manufacturing is evolving because of technology like additive manufacturing (AM). The mobility and compactness of AM are what make it desirable for many industry sectors. The U.S. Navy has shown interest in deploying AM on ships as it could alleviate their dependency on off-route docking to recharge supplies. However, the U.S. Navy's aspiration is currently hindered due to harsh ship-borne environments that degrade AM part quality.

This thesis focuses on vertical base vibration effects on AM part quality. An introduction is first given in Chapter 1 to familiarize the reader with the U.S. Navy's predicament. The …

A Geometric Description Of The Set Of Stabilizing Pid Controllers, Keqin Gu, Qian Ma, Huiqing Zhou, Mahzoon Salma, Xingzi Yang

SIUE Faculty Research, Scholarship, and Creative Activity

This article developed a new method to described the set of stabilizing PID control. The method is based on D-parameterization with natural description of the set. It was found that the stability crossing surface is a ruled surface that is completely determined by a curve known as discriminant. The discriminant is divided into sectors at the cusps. Corresponding to the sectors, the stability crossing surface is divided into positive and negative patches. A systematic study is conducted to identify the regions with a fixed number of right half-plane characteristic roots. The crossing directions of characteristic roots for positive patches and …

Bicycle Wheel Aerodynamics Predictions Using Cfd: Efficiency Using Blade Element Method, Drew Vigne

Honors Undergraduate Theses

The cycling industry has long relied on expensive wind tunnel testing when designing aerodynamic products, particularly in the context of wheels which account for 10 to 15 percent of a cyclist's total aerodynamic drag. With the recent advent of Computational Fluid Dynamics (CFD), the industry now has an economical tool to supplement the wheel design process; however, the complex nature of rotating spoked wheels requires high resolution meshes to model at acceptable fidelity. This research investigates an alternative CFD method that lowers the computational cost of modeling aerodynamic bicycle wheels by modeling spokes using Blade Element Method (BEM). Two CFD …

The Effect Of Dynamic Span Wise Bending On The Forces Of A Pitching Flat Plate, Manoj Prabakar Sargunaraj

Electronic Theses and Dissertations, 2020-2023

A novel experiment has been conducted to investigate the effect of dynamic spanwise bending on the formation of a dynamic stall vortex on a rapidly pitching flat plate. Experiments have been performed in a towing tank at different nondimensional pitch rates (Kp) in the range of 0.4112 < Kp < 0.8225, and four maximum pitch angles (30° , 45°, 60°, and 90°) at a Reynolds number of 12,000. Synchronized direct force measurements and particle image velocimetry (PIV) are used to characterize the effect of bending on the unsteady forces and the flow field. An unsteady analytical model based on the bending and pitching kinematics is used to model the lift force histories. It is found that a spanwise bending of a pitching wing alleviated the unsteady lift forces. However, the main contribution was found to come from the non-circulatory forces. The circulation and pressure analysis of the pitching wing revealed little or no sensitivity to the wing bending motions examined.

Localization Of Stationary Source Of Floor Vibration Using The Steered Response Power Method, Mohammad Royvaran

Theses and Dissertations--Civil Engineering

If the generated vibration in a building exceeds the acceptable limit design for a floor system, it is necessary to identify the source of vibration, a process known as localization. The objective of this study is the localization of stationary vibration sources, and the approach used is the steered response power (SRP) method. This method has already been shown to work well for wireless and acoustical applications to locate transmitter and sound sources, respectively. To the writer’s knowledge, this study is the first application of the SRP method to locate vibration sources using floor vibration measurements. However, because waves behave …

Prediction Of Noise Emissions Using Panel Contribution Analysis Supplemented With Scale Modeling, Gong Cheng

Theses and Dissertations--Mechanical and Aerospace Engineering

Panel contribution analysis (PCA) can be used to predict machinery noise emissions, component contributions, and to assess the impact of sound reduction treatments. PCA is a measurement approach that is advantageous for complex machinery that is not easily modeled using conventional numerical analysis approaches. In this research, PCA is combined with scale modeling in order to speed up the necessary measurement work. Moreover, the method can be applied to much larger machinery and noise emissions can be assessed prior to locating and installing the equipment. This eliminates the necessity to use voluminous anechoic chambers.

The machinery is first discretized into …

Electromagnetic Formation Control Using Frequency Multiplexing, Zahra Abbasi

Theses and Dissertations--Mechanical and Aerospace Engineering

This dissertation addresses control of relative positions and orientations of formation flying satellites using magnetic interactions. Electromagnetic formation flight (EMFF) is implemented, in which each satellite is equipped with a set of electromagnetic coils to generate an electromagnetic field. Traditional EMFF technique applies DC magnetic fields which lead to a nonlinear and highly coupled formation dynamics that allow for only position or orientation control of the satellites. We present a new frequency multiplexing method, which is a technique that uses multi-frequency sinusoidal controls, to approximately decouple the formation dynamics and to provide enough controls for both position and orientation control. …

Novel New Modeling Procedure For Industrial Machinery With Nonlinear Connections, Steven Whitican

Dissertations, Master's Theses and Master's Reports

Given current timelines for rolling out production at volume, the ability to model portions of the production process is of paramount importance. To model production, high-fidelity models of production assets must be obtained. The production assets are comprised of linear and nonlinear structures. The linear structures are well understood and defined. Significant work has, and is, being done to understand the nonlinear components. This work focuses on developing and correlating a model of a nonlinear component. The component studied and modeled is a linear guide. Linear guides are bearings which facilitate translational motion of machine axes. An accurate model of …

Development Of The Carbon Nanotube Thermoacoustic Loudspeaker, Troy Bouman

Dissertations, Master's Theses and Master's Reports

Traditional speakers make sound by attaching a coil to a cone and moving that coil back and forth in a magnetic field (aka moving coil loudspeakers). The physics behind how to generate sound via this velocity boundary condition has largely been unchanged for over a hundred years. Interestingly, around the time moving coil loudspeakers were first investigated the idea of using heat to generate sound was also known. These thermoacoustic speakers heat and cool a thin material at acoustic frequencies to generate the pressure wave (i.e. they use a thermal boundary condition). Unfortunately, when the thermoacoustic principle was initially discovered …

Development Of A Method To Model An Enclosed, Coaxial Carbon Nanotube Speaker With Experimental Validation, Suraj Prabhu

Dissertations, Master's Theses and Master's Reports

Carbon nanotube (CNT) speakers operate on heat as compared to conventional loudspeakers that operate on vibration. CNT speakers are extremely lightweight, stretchable, flexible, and have high operating temperatures. Due to these advantages, CNT speakers are being considered as a viable replacement option for conventional loudspeakers. One such application is automotive exhaust noise control. The goal of this research is to design an enclosed, coaxial CNT speaker and to develop a modeling method to model this speaker using COMSOL Multiphysics.

As part of this research, an enclosed, coaxial CNT speaker was designed and manufactured for automotive exhaust noise control. The first …

Assessing The Comfort Of Earplugs: Development And Validation Of The French Version Of The Coprod Questionnaire, Jonathan Terroir, Nellie Perrin, Pascal Wild, Olivier Doutres, Franck Sgard, Chantal Gauvin, Alessia Negrini

Études primaires

Earplugs are a common form of protection for workers exposed to hazardous noise levels. Their comfort directly impacts the effective protection by influencing their consistent and correct use. Nevertheless, comfort definition may vary according to the studies. Thus, a previous review of the literature has shown that to improve our understanding of perceived comfort and to reduce measurement variability, it is advisable to consider comfort through a multidimensional construct (physical, acoustical, functional and psychological). On this basis, the COPROD (COnfort des PROtections auDitives/COmfort of hearing PROtection Devices) questionnaire was developed. It is intended for people working in noisy environments. Nine …

Design And Testing Of A Feed-Forward Control System For Deployable Vortex Generators Dependent On Angle Of Attack, Solomon B. Whitmire, Christopher J. Chapanar, Kirklin M. Anderson, Nickalus R. Amon, Daniel W. Chech

Williams Honors College, Honors Research Projects

A vortex generator (VG hereafter) is a common feature of an aircraft wing that disturbs the flow on the leading edge of the wing, thus energizing the boundary layer and reducing flow separation. For an aircraft experiencing flow separation, VGs can increase the lift-to-drag ratio of the wing and prevent stall; however, if flow separation isn’t an issue, the unnecessary frontal area of the VGs has the potential to produce parasitic drag. This study seeks to determine whether the use of a deployment system can improve the performance of VG’s by raising or lowering them depending on the angle of …

Foldibot The Autonomous Clothes Folder, Jacob Kittinger, Braden Glasgow, Steven Shimko

Williams Honors College, Honors Research Projects

As society becomes more technologically advanced, so does the demand for innovative products that save time; products like the Roomba have revolutionized household chores. Our teams’ vision was to develop a solution for another time-consuming household chore: folding laundry. The goal of this project was to conceptually design a marketable “robot” capable of autonomously folding clothes and explore a potential design by prototyping and testing it. Our team utilized our culmination of knowledge acquired over five years of engineering studies to turn a “pen and paper” sketch into a functioning prototype; this project used engineering tools such as a Weighted …

Road Racing Aerodynamic Simulation + Testing, Jack Sawyer

Williams Honors College, Honors Research Projects

There are multiple goals for this project. The first goal of this project is to design, assemble and simulate additional aerodynamic components. Another goal is to create a product that can analyze various angles of attack of Aerodynamic components. The product will be used on, or off the track to determine the lift coefficients of vehicles at varying speeds. I will be using my 1992 Honda Civic for testing and compare my physical results to my simulated tests.

The project did come with a list of design and manufacturing challenges along with additional finical cost which has resulted in some …

Less Commute Miles. Decreased Tire Wear. What Would You Do?, Dylan Schwarz, Brendon M. Ford, Brandon D. Hadinger, Abbie N. Pearce, Jacinta M. Pikunas

Williams Honors College, Honors Research Projects

With the flagrant recognition of the coronavirus as one of those most impactful viruses in the history of the world, it is important to study how the effects of such a disease can create troublesome ripple effects in the world. Covid-19 has caused the death of hundreds of thousands of individuals and has negatively impacted the lives of American’s all across the country during the nationwide lockdown. Decreased work commuters, minimal road travel, and little need for car repairs hit the Goodyear Tire and Rubber Company hard. The University of Akron has teamed up with Goodyear to explore such effects …

Entertainment 721, Mark Hendricks, Noah John, Jadon Vanyo, Chelsea Payne

Williams Honors College, Honors Research Projects

The goal of this project was to design a luxury, aesthetically pleasing entertainment system with a TV lift mechanism that could be remote controlled. The design would also include a cooling cabinet for gaming systems, a remote locking system, and additional storage. Using a morphological chart and weighted decision matrix for each subsystem key features were determined to be included in the design. Several performance benchmarks were determined to accomplish the team’s design. Almost every benchmark was successful in the build of the first prototype. Several heat calculations and FEA analyses were performed on the system to ensure the success …

Application Of Carbon Nanotube Thermophones As Duct Noise Cancelling Speakers: Using New Technology With Old Theories, Stephania M. Vaglica

Dissertations, Master's Theses and Master's Reports

Certain materials can produce sound through heat fluctuations. In recent times, the material capable of this was discovered to be Carbon Nanotubes (CNT). The idea is to create a flexible speaker that can be made into any shape or form to create sound. Once a speaker has been created, an active noise control system can be designed to cancel loud sounds in building and pipe ducts. This technology, similar to noise cancelling headphones, allows a user to create a modular system to mitigate noise in everyday life. Thus, the purpose of this research is to illustrate the abilities of a …

Experimental Evaluation And Simulation Of Torque Transmissibility Frequency Response Functions Of Vibration Isolators And Absorbers For Drivetrain Applications, Luke Jurmu

Dissertations, Master's Theses and Master's Reports

Four studies involving torsional vibration isolation performance of automotive drivetrain components, make up this dissertation. One study features a prototype planetary torsional vibration absorber, a unique device that targets low frequency torsion modes in automotive drivetrains. Two studies feature experiments on several torque converters, clutch locked and open, to validate models of the hardware. The last study details experiments on a centrifugal pendulum absorber in a torque converter, to characterize the viscous friction while submerged in automatic transmission fluid (ATF). The enclosed studies improve the state of the art of drivetrain vibration absorbers and isolators, by introducing a new vibration …