Acoustics, Dynamics, and Controls Commons^™

Gamelan Gong Directivity Dataset, Samuel D. Bellows, Dallin T. Harwood, Kent L. Gee, Micah R. Shepherd

Directivity

No abstract provided.

Experimental Uncertainty In Measurements Of Violin Impulse Response, Andrew Piacsek, Seth Lowery

All Faculty Scholarship for the College of the Sciences

Experiments that investigate how an individual musical instrument changes in response to subtle alterations must contend with measurement uncertainty, which typically arises from inconsistencies in the measurement setup. We quantify uncertainty in violin response measurements by measuring bridge admittance and radiatively of a single instrument that is repeatedly removed and reinstalled in our measurement apparatus. From this set of baseline measurements, we calculate the average and standard deviation of admittance and radiativity. The amount of variation observed in the baseline data is compared to the change in bridge admittance that occurred over several days due to a large and abrupt …

Jet Noise Reduction: A Fresh Start, Christopher K. Tam, Fang Q. Hu

Mathematics & Statistics Faculty Publications

Attempts to reduce jet noise began some 70 years ago. In the literature, there have been many publications written on this topic. By now, it is common knowledge that jet noise consists of a number of components. They possess different spectral and radiation characteristics and are generated by different mechanisms. It appears then that one may aim at the suppression of the noise of a single component instead of trying to reduce jet noise overall. The objective of the present project is to reduce large turbulence structures noise. It is the most dominant noise component radiating in the downstream direction. …

Bbt Acoustic Alternative Top Bracing Cadd Data Set-Norev-2022jun28, Bill Hemphill

STEM Guitar Project’s BBT Acoustic Kit

This electronic document file set consists of an overview presentation (PDF-formatted) file and companion video (MP4) and CADD files (DWG & DXF) for laser cutting the ETSU-developed alternate top bracing designs and marking templates for the STEM Guitar Project’s BBT (OM-sized) standard acoustic guitar kit. The three (3) alternative BBT top bracing designs in this release are
(a) a one-piece base for the standard kit's (Martin-style) bracing,
(b) 277 Ladder-style bracing, and
(c) an X-braced fan-style bracing similar to traditional European or so-called 'classical' acoustic guitars.

The CADD data set for each of the three (3) top bracing designs includes …

Control And Planning For Mobile Manipulators Used In Large Scale Manufacturing Processes, Joshua T. Nguyen

LSU Master's Theses

Sanding operations in industry is one of the few manufacturing tasks that has yet to achieve automation. Sanding tasks require skilled operators that have developed a sense of when a work piece is sufficiently sanded. In order to achieve automation in sanding with robotic systems, this developed sense, or intelligence, that human operators have needs to be understood and implemented in order to achieve, at the minimum, the same quality of work. The system will also need to have the equivalent reach of a human operator and not be constrained to a single, small workspace. This thesis developed solutions for …

Bbt Side Mold Assy, Bill Hemphill

STEM Guitar Project’s BBT Acoustic Kit

This electronic document file set covers the design and fabrication information of the ETSU Guitar Building Project’s BBT (OM-sized) Side Mold Assy for use with the STEM Guitar Project’s standard acoustic guitar kit. The extended 'as built' data set contains an overview file and companion video, the 'parent' CADD drawing, CADD data for laser etching and cutting a drill &/or layout template, CADD drawings in AutoCAD .DWG and .DXF R12 formats of the centerline tool paths for creating the mold assembly pieces on an AXYZ CNC router, and support documentation for CAM applications including router bit specifications, feeds, speed, multi-pass …

Investigation Of Topological Phonons In Acoustic Metamaterials, Wenting Cheng

Dissertations

Topological acoustics is a recent and intense area of research. It merges the knowledge of mathematical topology, condensed matter physics, and acoustics. At the same time, it has been pointed out that quasiperiodicity can greatly enhance the periodic table of topological systems. Because quasiperiodic patterns have an intrinsic global degree of freedom, which exists in the topological space called the hull of a pattern, where the shape traced in this topological space is called the phason. The hull augments the physical space, which opens a door to the physics of the integer quantum Hall effect (IQHE) in arbitrary dimensions. In …

A Central Compact Hybrid-Variable Method With Spectral-Like Resolution, Md Mahmudul Hasan

Open Access Theses & Dissertations

Numerical methods for hyperbolic conservation laws have been a driving force for theresearch in scientific computing and simulation science in the past decades, as many physical, biological, and engineering systems are governed by these equations, such as fluid mechanics, tumor growth, and virtual wind tunnel simulations. Despite the existence of many schemes in the literature, people have never stopped searching for more accurate and efficient methods for these problems. Indeed, the increasing complexity of systems in emerging applications demands better resolution of sub-grid scale phenomenon whereas classical methods usually fail to deliver high-fidelity simulation results of such systems within realistic …

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 …

Design Of Broadband Helmholtz Resonator Arrays Using The Radiation Impedance Method, Vidhya Rajendran, Andy Piacsek, Tomás Méndez Echenagucia

All Faculty Scholarship for the College of the Sciences

This paper describes the design process of a low-frequency sound absorptive panel composed of differently tuned Helmholtz resonators (HRs), considering size and fabrication constraints relevant for applications in the building sector. The paper focuses on cylindrical and spiral resonators with embedded necks that are thin and can achieve high absorption. the mutual interaction between the resonators was modeled based on the radiation impedance method and it plays a key component in enhancing the absorption performance of the array. The differential evolution search algorithm was used to design the resonators and modify their mutual interaction to derive the absorption performance of …

On-Ice Detection, Classification, Localization And Tracking Of Anthropogenic Acoustic Sources With Machine Learning, Steven J. Whitaker

Dissertations, Master's Theses and Master's Reports

Arctic acoustics have been of concern in recent years for the US navy. First-year ice is now the prevalent factor in ice coverage in the Arctic, which changes the previously understood acoustic properties. Due to the ice melting each year, anthropogenic sources in the Arctic region are more common: military exercises, shipping, and tourism. For the navy, it is of interest to detect, classify, localize, and track these sources to have situational awareness of these surroundings. Because the sources are on-water or on-ice, acoustic radiation propagates at a longer distance and so acoustics are the method by which the sources …

The Effect Of Noise-Reducing Acoustic Panels On The Noise Levels And Overall Safety Of Infant Sleep Machines, Pranav Poola

Journal of the South Carolina Academy of Science

Infant sleep machines (ISMs) are devices used to help infants fall asleep faster and stay asleep for longer amounts of time, yet they can often be too loud for infantile ears, which could potentially be dangerous. This research aimed to minimize the risks of infant sleep machines without reducing the effectiveness of the infant sleep machines themselves through the use of acoustic panels. Based on previous studies, it was hypothesized that the acoustic panels would reduce the noise levels of the ISM to less than recommended limits of 50 dB-A. A specific corner of a designated room was prepared with …

Development And Applications Of Adjoint-Based Aerodynamic And Aeroacoustic Multidisciplinary Optimization For Rotorcraft, Ramiz Omur Icke

Mechanical & Aerospace Engineering Theses & Dissertations

Urban Air Mobility (UAM) is one of the most popular proposed solutions for alleviating traffic problems in populated areas. In this context, the proposed types of vehicles mainly consist of rotors and propellers powered by electric motors. However, those rotary-wing components can contribute excessively to noise generation. Therefore, a significant noise concern emerges due to urban air vehicles in or around residential areas. Reducing noise emitted by air vehicles is critically important to improve public acceptance of such vehicles for operations in densely populated areas.

Two main objectives of the present dissertation are: (1) to expand the multidisciplinary optimization to …

Real-Time Monitoring Of Fdm 3d Printer For Fault Detection Using Machine Learning: A Bibliometric Study, Vaibhav Kisan Kadam, Satish Kumar, Arunkumar Bongale

Library Philosophy and Practice (e-journal)

Additive Manufacturing has wide application range including healthcare, Fashion, Manufacturing, Prototypes, Tooling etc. AM techniques are subjected to various defects that may be printing defects or anomalies in machine. There is gap between current AM techniques and smart manufacturing since current AM lacks in build sensors necessary for process monitoring and fault detection. Both of these issues can be solved by incorporating real-time monitoring into AM. So the study is carried out to identify recent work done in AM to improve current system. For this bibliometric study Scopus database is used, study is kept limited to year 2010-2021 and English …

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 …

The Beautiful Math Of Everything And You Included, E. Ozie

The Transdisciplinary STEAM+ Journal

This a reflection on how there is beautiful math to everything. An author's interpretation of matrices and mechanics in its relationship to someone's identity.

1. Test Data, Zhiqu Lu, Likun Zhang, Lei Cao

Gulf Research Program Data Sets

This data set contains recorded and processed bubble sounds under different conditions: a few bubbles vs. constant flow bubbles. Each condition is tested with nitrogen and with methane.

2. Modeling, Zhiqu Lu, Likun Zhang, Lei Cao

Gulf Research Program Data Sets

This data set contains the results for acoustic bubble modeling.

3. Localization, Zhiqu Lu, Likun Zhang, Lei Cao

Gulf Research Program Data Sets

This data set contains the results for oil leakage source localization.

4. Metadata Files, Zhiqu Lu, Likun Zhang, Lei Cao

Gulf Research Program Data Sets

This data set contains all ReadMe files for test data, modeling data, and localization data, as well as the corresponding codes.

5. Programs And Algorithms, Zhiqu Lu, Likun Zhang, Lei Cao

Gulf Research Program Data Sets

This data set contains all codes for the study.

6. Supplemental Materials, Zhiqu Lu, Likun Zhang, Lei Cao

Gulf Research Program Data Sets

This data set contains all conference presentations, manuscripts, technical reports, posters.

Understanding Of Aerosol Transmission Of Covid 19 In Indoor Environments, Adama Barro, Cathal O'Toole, Jacob S. Lopez, Matthew Quinones, Sherene Moore

Publications and Research

Our reason for discussing severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) or 2019 novel corona virus (Covid-19), is to understand its aerosol transmission characteristics in indoor spaces and to mitigate further spread of this disease by designing a new HVAC system. The problem that we are tackling is the spread of covid-19 droplets through aerosol transmission by looking at potential engineering solutions to the existing HVAC systems. The purpose is to eradicate the spread of the COVID-19 by testing indoor spaces in an effort to understand the effectiveness of ventilation controls. We believe that scientists and engineers have not …

Sound Vortex Diffraction Via Topological Charge In Phase Gradient Metagratings, Yangyang Fu, Chen Shen, Xiaohui Zhu, Junfei Li, Youwen Liu, Steven A. Crummer

Henry M. Rowan College of Engineering Departmental Research

Wave fields with orbital angular momentum (OAM) have been widely investigated in metasurfaces. By engineering acoustic metasurfaces with phase gradient elements, phase twisting is commonly used to obtain acoustic OAM. However, it has limited ability to manipulate sound vortices, and a more powerful mechanism for sound vortex manipulation is strongly desired. Here, we propose the diffraction mechanism to manipulate sound vortices in a cylindrical waveguide with phase gradient metagratings (PGMs). A sound vortex diffraction law is theoretically revealed based on the generalized conservation principle of topological charge. This diffraction law can explain and predict the complicated diffraction phenomena of sound …

Investigating The Feasibility And Stability For Modeling Acoustic Wave Scattering Using A Time-Domain Boundary Integral Equation With Impedance Boundary Condition, Michelle E. Rodio

Mathematics & Statistics Theses & Dissertations

Reducing aircraft noise is a major objective in the field of computational aeroacoustics. When designing next generation quiet and environmentally friendly aircraft, it is important to be able to accurately and efficiently predict the acoustic scattering by an aircraft body from a given noise source. Acoustic liners are an effective tool for aircraft noise reduction and are characterized by a frequency-dependent impedance. Converted into the time-domain using Fourier transforms, an impedance boundary condition can be used to simulate the acoustic wave scattering by geometric bodies treated with acoustic liners

This work considers using either an impedance or an admittance (inverse …

Dispersion Tuning And Route Reconfiguration Of Acoustic Waves In Valley Topological Phononic Crystals, Zhenhua Tian, Chen Shen, Junfei Li, Eric Reit, Hunter Bachman, Joshua E. S. Socolar, Steven A. Crummer, Tony Jun Huang

Henry M. Rowan College of Engineering Departmental Research

The valley degree of freedom in crystals offers great potential for manipulating classical waves, however, few studies have investigated valley states with complex wavenumbers, valley states in graded systems, or dispersion tuning for valley states. Here, we present tunable valley phononic crystals (PCs) composed of hybrid channel-cavity cells with three tunable parameters. Our PCs support valley states and Dirac cones with complex wavenumbers. They can be configured to form chirped valley PCs in which edge modes are slowed to zero group velocity states, where the energy at different frequencies accumulates at different designated locations. They enable multiple functionalities, including tuning …

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 …

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 …

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, …

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, …