Open Access. Powered by Scholars. Published by Universities.®

Acoustics, Dynamics, and Controls Commons

Open Access. Powered by Scholars. Published by Universities.®

1810 Full-Text Articles 2859 Authors 299911 Downloads 49 Institutions

All Articles in Acoustics, Dynamics, and Controls

Faceted Search

1810 full-text articles. Page 1 of 30.

Constraints On Acoustic Signaling Among Birds Breeding In Secondary Cavities: The Effects Of Weather, Cavity Material, And Noise On Sound Propagation, John P. Swaddle, Caitlin R. Kight, Saji Perera, Eduardo Davila-Reyes, Shena Sikora 2017 College of William and Mary

Constraints On Acoustic Signaling Among Birds Breeding In Secondary Cavities: The Effects Of Weather, Cavity Material, And Noise On Sound Propagation, John P. Swaddle, Caitlin R. Kight, Saji Perera, Eduardo Davila-Reyes, Shena Sikora

John Swaddle

Increasing evidence suggests that anthropogenic noise from urbanization affects animal acoustic communication. We investigated whether the begging calls of nestling Eastern Bluebirds (Sialia sialis) varied along a disturbance gradient of ambient noise. Contrary to our prediction and the results of a previous study of nestling Tree Swallows (Tachycineta bicolor), we found that nestling Eastern Bluebirds did not increase the amplitude or structural characteristics—including frequency, rate, and duration—of their vocalizations in response to ambient noise. However, we found that prevalent temperature and humidity conditions attenuated begging calls. Specifically, in warmer, more humid weather, vocalizations of nestling Eastern Bluebirds attenuated ...


Boundary Element Solutions To Wave Scattering By Surface Irregularities On A Fluid-Solid Interface, S. Shenoy, Thomas J. Rudolphi, F. J. Rizzo 2017 Iowa State University

Boundary Element Solutions To Wave Scattering By Surface Irregularities On A Fluid-Solid Interface, S. Shenoy, Thomas J. Rudolphi, F. J. Rizzo

Thomas Rudolphi

The boundary element method is used to solve fluid-solid half-space problems with fluid-filled dimples and air bubbles on the solid surface. The problems, formulated in the Fourier (frequency) domain, are described by the fullspace three-dimensional acoustic and elastodynamic boundary integral equations (BIE), with pressure and displacement serving as primary variables. The techniques developed are general and may be with any kind of incident wave, however, plane waves are used in all numerical experiments. The equations governing the acoustic region are first converted mathematically to equations like those of an elastic region. The two regions are coupled and solved for the ...


Active Management Assistant System For Embry-Riddle Ecocar 3 Hybrid Supervisory Control System, Matthew Nelson, Blair Cutting, Michael J. Aleardi 2016 Embry-Riddle Aeronautical University

Active Management Assistant System For Embry-Riddle Ecocar 3 Hybrid Supervisory Control System, Matthew Nelson, Blair Cutting, Michael J. Aleardi

Student Works

The Embry-Riddle EcoCAR 3 team is developing a prototype hybrid Chevrolet Camaro utilizing a customized vehicle powertrain controller. This controller is serving to ensure system safety, vehicle operation, and consumer drivability while also incorporating advanced driving aids to achieve both the desired performance levels one expects from a Camaro as well as vehicle efficiency. This vehicle must reach the team set vehicle technical specifications of a 4.9 second 0 to 60 time while maintaining a 53 miles per gallon gasoline equivalence rating.

In order to reach the efficiency goal, the team is developing an Active Management Assistance System utilizing ...


Design Of A Flexible Control Platform And Miniature In Vivo Robots For Laparo-Endoscopic Single-Site Surgeries, Lou P. Cubrich 2016 University of Nebraska-Lincoln

Design Of A Flexible Control Platform And Miniature In Vivo Robots For Laparo-Endoscopic Single-Site Surgeries, Lou P. Cubrich

Mechanical (and Materials) Engineering -- Dissertations, Theses, and Student Research

Minimally-invasive laparoscopic procedures have proven efficacy for a wide range of surgical procedures as well as benefits such as reducing scarring, infection, recovery time, and post-operative pain. While the procedures have many advantages, there are significant shortcomings such as limited instrument motion and reduced dexterity. In recent years, robotic surgical technology has overcome some of these limitations and has become an effective tool for many types of surgeries. These robotic platforms typically have an increased workspace, greater dexterity, improved ergonomics, and finer control than traditional laparoscopic methods. This thesis presents the designs of both a four degree-of-freedom (DOF) and 5-DOF ...


Dynamic Responses Of Wheel-Rail Systems With Block Dampers, TzuYu Tseng 2016 University of Nebraska-Lincoln

Dynamic Responses Of Wheel-Rail Systems With Block Dampers, Tzuyu Tseng

Mechanical (and Materials) Engineering -- Dissertations, Theses, and Student Research

The wheel-rail interaction problem has been widely studied in the past few decades. In this problem, dynamic responses at the contact areas remain the central issue since they induce damage to the rail over time. In particular, the dynamic responses at the contact areas between the wheels and rails present difficulties in understanding and mathematical modeling. Even with the computer power one has today, its mathematical modeling employs the versatile numerical analysis method, the finite element method (FEM) remains a formidable challenge due to its extremely small contact areas and in turn the extremely high stress levels. In addition, friction ...


3-Axis Automated Probe Traverse For Aerodynamic Testing, Tananant Boonya-ananta, Ricky Wai, Zander Oostman, Teyvon Brooks 2016 California Polytechnic State University, San Luis Obispo

3-Axis Automated Probe Traverse For Aerodynamic Testing, Tananant Boonya-Ananta, Ricky Wai, Zander Oostman, Teyvon Brooks

Mechanical Engineering

Our primary objective is to design, build, and test an automated traverse to hold measurement probes in Cal Poly’s low speed wind tunnel. The device should cause minimal flow disturbance. It’s movements must be able to cover eighty percent of the three-dimensional test section. The device should have a mounting point for interchangeable probes. The assembly is to be integrated with the current frame structure on the wind tunnel test section, and should allow very minimal deflection of the measurement probe. The user should be able to control the motion of the traverse via a computer interface which ...


Dynamic Monitoring And Life Prediction Of Internal Strain-Gage Balances, David Leon Yoder 2016 University of Tennessee, Knoxville

Dynamic Monitoring And Life Prediction Of Internal Strain-Gage Balances, David Leon Yoder

Masters Theses

Wind tunnel test customers continue to push the limits by producing air vehicle designs that produce high aerodynamic loads at the desired test conditions. These loads are a combination of steady aerodynamic, unsteady aerodynamic, and inertial forces. A methodology to monitor the health of a wind tunnel strain-gage balance has been developed. The objective of this methodology is to define the stress limits of the balance and monitor these limits so the balance can be safely tested without failure of the balance. A balance failure could result in costly damage to the wind tunnel model, support system, and the wind ...


Bridge Damage Detection Using Spatiotemporal Patterns Extracted From Dense Sensor Network, Chao Liu, Yongqiang Gong, Simon Laflamme, Brent M. Phares, Soumik Sarkar 2016 Iowa State University

Bridge Damage Detection Using Spatiotemporal Patterns Extracted From Dense Sensor Network, Chao Liu, Yongqiang Gong, Simon Laflamme, Brent M. Phares, Soumik Sarkar

Civil, Construction and Environmental Engineering Publications

The alarmingly degrading state of transportation infrastructures combined with their key societal and economic importance calls for automatic condition assessment methods to facilitate smart management of maintenance and repairs. With the advent of ubiquitous sensing and communication capabilities, scalable data-driven approaches is of great interest, as it can utilize large volume of streaming data without requiring detailed physical models that can be inaccurate and computationally expensive to run. Properly designed, a data-driven methodology could enable fast and automatic evaluation of infrastructures, discovery of causal dependencies among various sub-system dynamic responses, and decision making with uncertainties and lack of labeled data ...


A Bioinspired Modification For Uas Propeller/Rotor Noise Reduction, Mark N. Callender 2016 Middle Tennessee State University

A Bioinspired Modification For Uas Propeller/Rotor Noise Reduction, Mark N. Callender

ASA Multidisciplinary Research Symposium

This projects presents a bioinspired modification to UAS propellers/rotors for noise reduction. Sound pressure levels (SPL) and thrust for modified propellers were compared to a baseline propeller. The bioinspired modification yielded lower SPL with a requisite increase in rpm in order to maintain a chosen level of thrust.


The Simulation For Ultrasonic Testing Based On Frequency-Phase Coded Excitation, JiaYing Zhang, WenLong Tian, Tie Gang, Sen Cong, ZhaoYang Sheng 2016 Harbin Institute of Technology

The Simulation For Ultrasonic Testing Based On Frequency-Phase Coded Excitation, Jiaying Zhang, Wenlong Tian, Tie Gang, Sen Cong, Zhaoyang Sheng

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.


Sound Data Collection And Transmission Noise Reduction, Bradley Cockrel 2016 Western Kentucky University

Sound Data Collection And Transmission Noise Reduction, Bradley Cockrel

Honors College Capstone Experience/Thesis Projects

The WKU Engineering Department Senior Student Team, The Synchronizers, has been contracted to modify a MTD transmission’s sound characteristics. This project entails developing a sound data acquisition apparatus and method, developing a sound test stand which will fully load the transmission and load characteristics, and suggesting modes of sound modification. The Sound Data Acquisition method entails using a specialized microphone calibrated to operate on IOS devices to measure Sound Intensity. The sound intensity will be found over a collective area, in order to evaluate to the sound power generated. The sound test stand will consist of a system designed ...


The Effect Of Honeycomb Cavity: Acoustic Performance Of A Double-Leaf Micro Perforated Panel, Yuxian Huang, Kai Ming Li 2016 Purdue University

The Effect Of Honeycomb Cavity: Acoustic Performance Of A Double-Leaf Micro Perforated Panel, Yuxian Huang, Kai Ming Li

The Summer Undergraduate Research Fellowship (SURF) Symposium

A micro perforated panel (MPP) is a device consisting of a thin plate and submillimeter perforations for reducing low frequency noise. MPPs have many advantages compared to traditional sound absorption materials, such as durability and designability, and they can be used in a variety of places such as room interior designs, passenger and crew compartments of aircrafts and combustion engines. The models in this study were designed and fabricated with the latest 3-D printing technology. The transmission loss and sound absorption coefficient of the 3-D printed double-leaf MPPs with honeycomb cavities were studied. According to the established theory, MPPs work ...


Development Of Data Analytics Tools For Acoustic Measurement Of Positive Displacement Machines, Dan Ding, Monika Ivantysynova, Paul Kalbfleisch 2016 Purdue University

Development Of Data Analytics Tools For Acoustic Measurement Of Positive Displacement Machines, Dan Ding, Monika Ivantysynova, Paul Kalbfleisch

The Summer Undergraduate Research Fellowship (SURF) Symposium

Noise control is an important factor in evaluating the design of positive displacement machines. This research project aims to develop new tools in MATLAB, with emphasis on visual approaches, to comprehensively characterize the noise generated by positive displacement machines in spatial, temporal and frequency domains. Sound pressure level (SPL), sound intensity level (SIL) and loudness were calculated and plotted on a measurement surface surrounding the pump, which illustrates the spatial distribution of the sound field. In order to highlight the phenomenon within specific frequency bands, Butterworth filters were used to isolate desired frequencies, such that specific harmonic content or 1 ...


The Influence Of Thermal Conditions On The Thermomechanics Of Particulate-Composite, Mock Explosive Samples Under Near-Resonant Excitation, Jaylon B. Tucker, Allison R. Range, Jeffrey F. Rhoads 2016 Purdue University

The Influence Of Thermal Conditions On The Thermomechanics Of Particulate-Composite, Mock Explosive Samples Under Near-Resonant Excitation, Jaylon B. Tucker, Allison R. Range, Jeffrey F. Rhoads

The Summer Undergraduate Research Fellowship (SURF) Symposium

Vapor detection is one of the most effective ways to find hidden plastic-bonded explosives in the field today. In recent years, it has been demonstrated that providing near-resonant vibratory excitation to explosives dramatically increases their vapor pressure, allowing for easier detection. Unfortunately, there currently exists a limited understanding of the thermomechanics of energetic material. This study seeks to help fill this technical void by exploring the thermomechanics of mock plastic-bonded explosives using direct mechanical excitation with varying thermal conditions. Using two different ambient thermal boundary conditions (insulated geometric boundaries and boundaries with free convection), a 7" by 10" by 0 ...


Dynamic Behavior Of A Clamped-Clamped Bi-Stable Laminate For Energy Harvesting, Ajay V. Kumar, Andres F. Arrieta Ph.D., Myungwon Hwang 2016 Purdue University

Dynamic Behavior Of A Clamped-Clamped Bi-Stable Laminate For Energy Harvesting, Ajay V. Kumar, Andres F. Arrieta Ph.D., Myungwon Hwang

The Summer Undergraduate Research Fellowship (SURF) Symposium

Multi-stable laminates have many applications in morphing structures, energy harvesting devices, and metamaterials due to the specific characteristics attributed to the exhibited stable states. Changes between stable states allow for large deflections, on-demand variation of the stiffness of compliant structures embedded within these elements, and control of effective dynamic properties in periodic lattices. These changes in state can be accessed via a snap-through instability triggered by introducing a well-defined activation energy. The resulting oscillations could enable broadband energy harvesting via piezoelectric transduction and resistive circuits. In this paper, a clamped-clamped bi-stable laminate is studied to understand the behavior of the ...


Lattice Boltzmann Methods For Wind Energy Analysis, Stephen Lloyd Wood 2016 University of Tennessee, Knoxville

Lattice Boltzmann Methods For Wind Energy Analysis, Stephen Lloyd Wood

Doctoral Dissertations

An estimate of the United States wind potential conducted in 2011 found that the energy available at an altitude of 80 meters is approximately triple the wind energy available 50 meters above ground. In 2012, 43% of all new electricity generation installed in the U.S. (13.1 GW) came from wind power. The majority of this power, 79%, comes from large utility scale turbines that are being manufactured at unprecedented sizes. Existing wind plants operate with a capacity factor of only approximately 30%. Measurements have shown that the turbulent wake of a turbine persists for many rotor diameters, inducing ...


Delay-Independent Stability Analysis Of Linear Time-Delay Systems Based On Frequency, Xianwei Li, Huijun Gao, Keqin Gu 2016 Harbin Institute of Technology

Delay-Independent Stability Analysis Of Linear Time-Delay Systems Based On Frequency, Xianwei Li, Huijun Gao, Keqin Gu

SIUE Faculty Research, Scholarship, and Creative Activity

This paper studies strong delay-independent stability of linear time-invariant systems. It is known that delay-independent stability of time-delay systems is equivalent to some frequency-dependent linear matrix inequalities. To reduce or eliminate conservatism of stability criteria, the frequency domain is discretized into several sub-intervals, and piecewise constant Lyapunov matrices are employed to analyze the frequency-dependent stability condition. Applying the generalized Kalman–Yakubovich–Popov lemma, new necessary and sufficient criteria are then obtained for strong delay-independent stability of systems with a single delay. The effectiveness of the proposed method is illustrated by a numerical example.


Development Of The Compact Jet Engine Simulator From Concept To Useful Test Rig, Henry H. Haskin 2016 Old Dominion University

Development Of The Compact Jet Engine Simulator From Concept To Useful Test Rig, Henry H. Haskin

Mechanical & Aerospace Engineering Theses & Dissertations

Two Compact Jet Engine Simulator (CJES) units were designed for integrated wind tunnel acoustic experiments involving a Hybrid Wing Body (HWB) vehicle. To meet the 5.8% scale of the HWB model, Ultra Compact Combustor technology from the Air Force Research Laboratory was used. The CJES units were built and integrated with a control system in the NASA Langley Low Speed Aero acoustic Wind Tunnel. The combustor liners, plug—vane and flow conditioner components were built in-house at Langley Research Center. The operation of the CJES units was mapped and fixes found for combustor instability tones and rig flow noise ...


Experimental Building Demonstration Model With Viscous Fluid Dampers, Blake Thomas Reeve, Brianna Jean Kufa, Aden Malek Stepanians, Sophie Carmion Ratkovich 2016 California Polytechnic State University, San Luis Obispo

Experimental Building Demonstration Model With Viscous Fluid Dampers, Blake Thomas Reeve, Brianna Jean Kufa, Aden Malek Stepanians, Sophie Carmion Ratkovich

Architectural Engineering

The Architectural Engineering major places a heavy emphasis on structural dynamics and the role of wind and seismic loading in building analysis and design. Buildings of high importance that are critical to community function, such as hospitals, often utilize supplemental damping devices like supplemental viscous fluid dampers or base isolators to reduce the overall demands on the structural system. The design and analysis of these dampers are typically not taught at the undergraduate level, and is frequently performed by mechanical engineers, in lieu of structural engineers.

To better understand and research building behavior with supplemental damping devices, our multi-disciplinary team ...


Physical Testing Of Potential Football Helmet Design Enhancements, Michael Jeremy Schuster 2016 California Polytechnic State University, San Luis Obispo

Physical Testing Of Potential Football Helmet Design Enhancements, Michael Jeremy Schuster

Master's Theses and Project Reports

Football is a much loved sport in the United States. Unfortunately, it is also hard on the players and puts them at very high risk of concussion. To combat this an inventor in Santa Barbara brought a new design to Cal Poly to be tested.

The design was tested in small scale first in order to make some preliminary conclusions about the design. In order to fully test the helmet design; however, full scale testing was required. In order to carry out this testing a drop tower was built based on National Operating Committee on Standards for Athletic Equipment, NOCSAE ...


Digital Commons powered by bepress