Acoustics, Dynamics, and Controls Commons^™

Adaptable Clean Energy Laboratory, Joao Marcelo Rocha Belmonte, Marc D. Compere

Sustainability Conference

The Adaptable Clean Energy (ACE) Lab is a real-world, long term, test platform that will guide the courses of the Energy Systems track. The lab will provide realistic electrical and HVAC loads that mimic a solar powered office. The lab is a 20’ high cube shipping container modified with a door, windows, lights computers, air conditioner and appliances. The lab is Net-Zero and powered entirely from the sun. Two insulation test sections expose the exterior walls for research access to real external heat loads in a real building

Dual-Axis Solar Tracker, Bryan Kennedy

All Undergraduate Projects

Renewable energies, and fuels that are not fossil fuel-based, are one of the prolific topics of debate in modern society. With climate change now becoming a primary focus for scientists and innovators of today, one of the areas for the largest amount of potential and growth is that of the capturing and utilization of Solar Energy. This method involves using a mechanical system to track the progression of the sun as it traverses the sky throughout the day. A dual-axis solar tracker such as the one designed and built for this project, can follow the sun both azimuthally and in …

Multi-Objective Optimization Of Multi-Loop Control Systems, Yuekun Chen

Theses, Dissertations and Capstones

Cascade Control systems are composed of inner and outer control loops. Compared to the traditional single feedback controls, the structure of cascade controls is more complex. As a result, the implementation of these control methods is costly because extra sensors are needed to measure the inner process states. On the other side, cascade control algorithms can significantly improve the controlled system performance if they are designed properly. For instance, cascade control strategies can act faster than single feedback methods to prevent undesired disturbances, which can drive the controlled system’s output away from its target value, from spreading through the process. …

Active Noise Control Using Carbon Nanotube Thermophones: Case Study For An Automotive Hvac Application, Walker H. Nelson

Dissertations, Master's Theses and Master's Reports

The goal of this project was to reduce the overall noise levels emitted by the HVAC components in a vehicle’s cabin. More specifically, the feasibility of achieving this goal using two key technologies was investigated.

The first of these technologies, Active Noise Control (ANC), is a noise attenuation technique that relies on destructive interference that “cancels” unwanted noise. Typically used in situations where physical constraints prevent passive attenuation techniques from being used, ANC is known for its high size-to-effectiveness ratio. This benefit cannot be gained without a cost however; the complexity of ANC systems is significantly higher than their passive …

Dynamic Loading Experimentation And Surface Imaging Of Pressure Vessel Loadcell Fractures, Austin T. Sumner

Honors College Theses

Pressure vessels are very common pieces of equipment in industry and they are used for a variety of applications. It is standard in industry to rest pressure vessels on load cells. For some special cases, the pressure vessels are rested on load cells instead of solid foundation. Pressure vessels and their loadcells are generally designed for static environmental conditions and loading and tend to experience adverse effects when exposed to dynamic environments, such as hurricanes and earthquakes. These adverse-loading conditions cause vibrations and asymmetrical loading on the load cells, which can concurrently cause unexpected failure. This research investigates the effects …

Numerical And Experimental Studies Of Blocked Force Determination On An Offset Interface For Plate And Shell Structures And Duct Acoustic Systems, Keyu Chen

Theses and Dissertations--Mechanical and Aerospace Engineering

Blocked force determination is an alternative to the more routine method of inverse force determination using classical transfer path analysis. One advantage of determining blocked forces is that there is no need for the source to be detached or isolated from the system. Another advantage is that calculated blocked forces are appropriate when modifications are made on the receiver side of the interface. This insures that the blocked forces are suitable for utilization in analysis models where receiver system modifications are considered. Difficulties in using the approach arise when interface locations are difficult to instrument. This thesis demonstrates that blocked …

Filtered-Dynamic-Inversion Control For Unknown Minimum-Phase Systems With Unknown Relative Degree, Sumit Suryakant Kamat

Theses and Dissertations--Mechanical and Aerospace Engineering

We present filtered-dynamic-inversion (FDI) control for unknown linear time-invariant systems that are multi-input multi-output and minimum phase with unknown-but-bounded relative degree. This FDI controller requires limited model information, specifically, knowledge of an upper bound on the relative degree and knowledge of the first nonzero Markov parameter. The FDI controller is a single-parameter high-parameter-stabilizing controller that is robust to uncertainty in the relative degree. We characterize the stability of the closed-loop system. We present numerical examples, where the FDI controller is implemented in feedback with mathematical and physical systems. The numerical examples demonstrate that the FDI controller for unknown relative degree …

Development And Application Of Novel Sound Absorbers, Weiyun Liu

Theses and Dissertations--Mechanical and Aerospace Engineering

The sound absorbers in most common use today are porous materials like fibers and foams. This work examines three alternatives to porous absorbers: microperforated panels, acoustic fabrics, and additively manufactured absorbers. The research is a combination of design, measurement and characterization of their properties, and analysis.

Microperforated panels are thin metallic or plastic panels with sub-millimeter size holes or perforations. Sound absorption can be tuned by adjusting the spacing between the panel and a cavity behind the panel. Several different configurations were considered where the geometry behind the panel was divided up into channels of varying length and cross-sectional area. …

Using Transfer Path Analysis And Frequency Based Substructuring To Develop A Robust Vibration Laboratory Dynamic Test Fixture Design Process, Cora Taylor

Dissertations, Master's Theses and Master's Reports

The objective of this research is to determine a robust method for designing shock and vibration laboratory test fixtures that accurately reproduce the field environment for the component of interest. The methods presented in this research examine the boundary conditions presented unto the component of interest through transfer path analysis with the intent of reproducing the next-structure attachment impedance with a laboratory test fixture of one and two attachments. The first method includes only using the next-structure relative motion and stiffness to design a test fixture, while the second method uses an optimization algorithm to develop a lumped parameter model …

Experimental Evaluation Of An Rwd Vehicle With Parameter Extraction For Analytical Modeling And Evaluation, Jon Furlich

Dissertations, Master's Theses and Master's Reports

This study was conducted to perform experimental vibration testing on a light duty rear wheel drive vehicle. The vehicle is known to have excessive longitudinal acceleration response perceived after step changes in the driver torque command. The excessive response includes shuffle and clunk transients. Experimental testing was performed to understand the coupling between driver torque commands and peak shuffle oscillations. Data was also targeted to understand the coupling between driveline torsional oscillations and longitudinal vehicle vibrations. This data was also used to establish vehicle parameters for use in an analytical CAE model of the driveline and coupling. Driver applied tip-in …

Deep Learning Of Nonlinear Dynamical System, Aditya Wagh

Dissertations, Master's Theses and Master's Reports

A data-driven approach, such as neural networks, is an alternative to traditional parametric-model methods for nonlinear system identification. Recently, long Short- Term Memory (LSTM) neural networks have been studied to model nonlinear dynamical systems. However, many of these contributions are made considering that the input to the system is known or measurable, which often may not be the case. This thesis presents a method based on LSTM for output-only modeling, identification, and prediction of nonlinear systems. A numerical study is performed and discussed on Duffing systems with various cubic nonlinearity.

Analysis Of A Circular Resonant Plate For Shock Testing, Jon Markl

Dissertations, Master's Theses and Master's Reports

Designing a resonant plate for shock test specifications involves an understanding of how a system will respond with a given set of input and output locations in all three directions. To investigate how to effectively change the off-axis responses to meet test specifications, a finite element model (FEM) was created and examinations of input location/angle of impact, placement of the test fixture, and placement of the impact pad were conducted. The primary tool used to determine how a structure will respond to a given input at a given output on the test structure was done using the shock response spectra …

Experimental Characterization Of Spool Valve Flow Noise, Zachary Cohen

Dissertations, Master's Theses and Master's Reports

The purpose of this research was to experimentally measure the flow noise produced by a spool valve and compare with measurements of orifice flow noise to reduce flow noise modelling complexity. The similarities and differences are compared over a range of volume flow rates, back pressures, and cross section areas. The impact of down stream boundary conditions on the flow noise are also examined. The results are generalized and plotted against Froude number. The valve results are curve fit to generate empirical equations that can be used to predict flow noise under typical operating conditions. The valve and orifice data …

Dynamic Testing: An Experimental Approach To Defect Identification In Additive Manufactured Parts, Aimee Allen

Dissertations, Master's Theses and Master's Reports

Today’s additive manufacturing (AM) industry produces specialized parts at low volume or with complex geometries. Traditional testing methods are effective, but costly and time consuming to perform. The AM industry lacks an optimized testing method for identifying internal defects that occur in parts. The evaluation of multiple parts printed on the same build plate for internal defects using various nondestructive (dynamic) testing techniques is presented. From these experiments, perspective was gained on when and how dynamic testing can be used to find defects. Insight gained from these experiments can help the industry in future testing for internal defects.

Automated And Standardized Tools For Realistic, Generic Musculoskeletal Model Development, Trevor Rees Moon

Graduate Theses, Dissertations, and Problem Reports (ETD)

Human movement is an instinctive yet challenging task that involves complex interactions between the neuromusculoskeletal system and its interaction with the surrounding environment. One key obstacle in the understanding of human locomotion is the availability and validity of experimental data or computational models. Corresponding measurements describing the relationships of the nervous and musculoskeletal systems and their dynamics are highly variable. Likewise, computational models and musculoskeletal models in particular are vitally dependent on these measurements to define model behavior and mechanics. These measurements are often sparse and disparate due to unsystematic data collection containing variable methodologies and reporting conventions. To date, …

Topological Wave Insulators: A Review, Farzad Zangeneh-Nejad, Andrea Alù, Romain Fleury

Advanced Science Research Center

Originally discovered in condensed matter systems, topological insulators (TIs) have been ubiquitously extended to various fields of classical wave physics including photonics, phononics, acoustics, mechanics, and microwaves. In the bulk, like any other insulator, electronic TIs exhibit an excessively high resistance to the flow of mobile charges, prohibiting metallic conduction. On their surface, however, they support one-way conductive states with inherent protection against certain types of disorder and defects, defying the common physical wisdom of electronic transport in presence of impurities. When transposed to classical waves, TIs open a wealth of exciting engineering-oriented applications, such as robust routing, lasing, signal …

Conception D’Oreilles Artificielles Réalistes Dédiées À L’Étude Du Confort Acoustique Et Physique Des Protecteurs Auditifs Intra-Auriculaires, Simon Benacchio, Olivier Doutres, Éric Wagnac, Franck Sgard

Rapports de recherche scientifique

Au Québec, environ 360 000 travailleurs sont exposés quotidiennement à des niveaux de bruit susceptibles d’engendrer des problèmes d’audition. Les protecteurs auditifs individuels sont souvent utilisés pour pallier ce problème. Cependant, l’inconfort lié à l'utilisation de ces protecteurs limite la durée du port et donc l'efficacité de la protection. Le développement d'outils de conception acoustique minimisant les sources d’inconforts auditifs et physiques de ces protecteurs tout en assurant une atténuation adéquate constitue le contexte de cette recherche.

La présente étude se concentre sur deux indicateurs du confort associés au port des bouchons d’oreille : l’atténuation et l’effet d’occlusion. L’atténuation quantifie …

Fast Decision-Making Under Time And Resource Constraints, Kyle Gabriel Lassak

Graduate Theses, Dissertations, and Problem Reports (ETD)

Practical decision makers are inherently limited by computational and memory resources as well as the time available in which to make decisions. To cope with these limitations, humans actively seek methods which limit their resource demands by exploiting structure within the environment and exploiting a coupling between their sensing and actuation to form heuristics for fast decision-making. To date, such behavior has not been replicated in artificial agents. This research explores how heuristics may be incorporated into the decision-making process to quickly make high-quality decisions through the analysis of a prominent case study: the outfielder problem. In the outfielder problem, …

Implementation Of Radial Basis Function Artificial Neural Network Into An Adaptive Equivalent Consumption Minimization Strategy For Optimized Control Of A Hybrid Electric Vehicle, Thomas P. Harris

Graduate Theses, Dissertations, and Problem Reports (ETD)

Continued increases in the emission of greenhouse gases by passenger vehicles has accelerated the production of hybrid electric vehicles. With this increase in production, there has been a parallel demand for continuously improving strategies of hybrid electric vehicle control. The goal of an ideal control strategy is to maximize fuel economy while minimizing emissions. The design and implementation of an optimized control strategy is a complex challenge. Methods exist by which the globally optimal control strategy may be found. However, these methods are not applicable in real-world driving applications since these methods require a priori knowledge of the upcoming drive …

Design And Optimization Of Dynamic System For A One-Kw Free Piston Linear Engine Alternator-Gensets Program, Nima Zamani Meymian

Graduate Theses, Dissertations, and Problem Reports (ETD)

In power/energy systems, free-piston linear machines are referred to as a mechanism where the constrained crank motion is eliminated and replaced with free reciprocating piston motion. Depending on the application, the piston motion can be converted into other types of energy and includes compressed air/fluid, electricity, and high temperature/pressure gas. A research group at West Virginia University developed a free-piston linear engine alternator (LEA) in 1998 and have achieved significant accomplishment in the performance enhancement of the LEAs to date. The present LEA design incorporates flexure springs as energy restoration components and as bearing supports. The advantages of using flexure …