Acoustics, Dynamics, and Controls Commons^™

Ballasting System For An Autonomous Underwater Vehicle, Noura Rayes, Bahram Nassersharif, Zach Champney, Kyle Alessandro, Jason Mirandou

Senior Honors Projects

NOURA RAYES (Mechanical Engineering); Ballasting System for an Autonomous Underwater Vehicle Sponsor: Bahram Nassersharif (Mechanical Engineering)

Over the last year, our Mechanical Engineering Capstone team, Nautilus, has been working to design a ballasting system for various Autonomous Underwater Vehicles (AUVs) sponsored by Raytheon Technologies. Common AUV systems are used for a wide range of applications from environmental monitoring, oceanic exploration, to data collection. AUVs also have many technical advantages that make underwater tasks more efficient, cost-effective, and generally safer. Raytheon Technology, specifically, is looking to improve their existing ballasting mechanism for their AUVs to use for military defense. For this …

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 …

Ambient Temperature Phase Change Launcher, Johnny Molloy

Senior Honors Projects

JOHNNY MOLLOY (Mechanical Engineering) Ambient Temperature Phase Change Launcher Sponsor: Bahram Nassersharif (Mechanical Engineering)

Deployment of payloads stored in watertight cylindrical bodies in underwater environmental conditions are of interest to the marine and naval community. The proposed work will investigate the possibility of using inert carbon dioxide gas compressed into its liquid state and stored under pressure to launch payloads by means of expansion from a cylindrical tube. To suit the needs of the Naval Undersea Warfare Center (NUWC), this launching system must fire from up to 14 ft underwater, have two degrees of freedom, and the payload must not …

Cal Poly Fluid Power Vehicle Challenge 2022, Sangmin Sung, Eddy Rodriguez, Travis Welch, Jeremy Baechler, Kevin Pauls

Mechanical Engineering

In this report, the Featherweight Cycles design team puts forth the scope and overview of their design project, discusses background research and competitor analysis, and presents the project’s final design and manufacturing plans. The overall goal of this project is to fabricate and compete in the Fluid Power Vehicle Challenge, hosted by the National Fluid Power Association. To better define the design process, the team researched previous year’s designs from Cal Poly, as well as winning designs from the last two years to form a baseline of knowledge about competing schools’ designs. After researching multiple design paths, Featherweight Cycles chose …

New Mathematical Models For Acoustic Insertion Loss Of Fiberglass Lining In Hvac Duct, Michael Anthony Schwob

UNLV Theses, Dissertations, Professional Papers, and Capstones

The design objectives for HVAC air distribution systems are thermal comfort, good indoor air quality, energy efficiency, low construction cost, and appropriate indoor noise levels. The last objective requires that the designer can predict the attenuation of sound transmitted through an air duct. One form of attenuation commonly introduced to an air distribution system to achieve interior noise criteria is fiberglass liner. Past research has been conducted to obtain reliable and accurate insertion loss (IL) data for duct with fiberglass liner. Empirical efforts have relied on limited data sets. Computational efforts have produced numerical models that are not practical for …

Understanding The Nonlinear Dynamics Governing Vertical-Lift Vehicles With Variable-Speed, Fixed Rotors, Stephanie Vavra, Micah Busboom, Aleea Stanford, Keegan Moore

UNL Student Research Days Posters, Undergraduate

Problem: Traffic significantly limits travel in urban areas. • The NASA Urban Air Mobility Project is developing an air taxi as an alternative mean of transportation (Fig. 1).

Challenge: Operating rotors at different frequencies may cause the cabin to vibrate at high amplitudes. Such effects are currently unknown.

Objective: Understand the effect of variable speed rotors on passenger comfort.

From the reduced-order modeling simulations, it can be assumed that counteracting the rotor speed in-balances can reduce the displacement and vibrations experienced at the center of the wing. In other words, should a rotor not maintain its optimal operation speed, reducing …

Jet Engine Emissions And Vapor Contrail Reduction Through Increased Combustion Efficiency With The Aim To Mitigate Greenhouse Gases Emissions, Austin J. Brant

Honors College Theses

As society continues to globalize and advance in complexity, the increased demand for business aviation has caused the global travel rate of airlines to increase with each year. With this continual increase in aviation travel, the Federal Aviation Administration (FAA) predicts that the fuel consumption rate is to increase by 1.6 percent as of the year 2025. While this increase in fuel consumption is a positive trait of a thriving aviation community, concerns also arise regarding increased greenhouse gas emissions and enlarged contributions to the greenhouse effect. The most prevalent greenhouse gases associated with jet engine emissions are water vapor, …

The Effect Of Store-To-Store Energy Transfers On The Global Dynamics Of Aircraft, Guilherme Mainieri Eymael, Keegan J. Moore

UNL Student Research Days Posters, Undergraduate

This study analyzes the energy transfer mechanisms when nonlinear devices (stores) are attached to a linear model airplane. For that, a reduced-order model (ROM) was derived to simulate the first two flexible modes of vibration of the primary structure (aircraft) with one store in each wing. Each store can either be locked or unlocked. When locked, it only contributes as mass-effect, and when unlocked, it adds nonlinearity to the system. Simulations were then performed with either both stores locked, one store unlocked, or both stores unlocked. It was found that the attachment of nonlinear stores in the ROM changes the …

The Effect Of Store-To-Store Energy Transfers On The Global Dynamics Of Aircraft, Guilherme Mainieri Eymael

Honors Program: Senior Projects (Public)

This study analyzes the energy transfer mechanisms when nonlinear devices (stores) are attached to a linear model airplane. For that, a reduced-order model (ROM) was derived to simulate the first two flexible modes of vibration of the primary structure (aircraft) with one store in each wing. Each store can either be locked or unlocked. When locked, it only contributes as mass-effect, and when unlocked, it adds nonlinearity to the system. Simulations were then performed with either both stores locked, one store unlocked, or both stores unlocked. It was found that the attachment of nonlinear stores in the ROM changes the …

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 …

Baja Sae Semi-Active Suspension, Philip Pang, Stassa Cappos, Harrison Hirsch, John Deboer

Mechanical Engineering

This Final Design Review (FDR) Report outlines the senior design project of the Baja SAE Semi-Active Suspension group, which includes mechanical and electrical engineering students at California Polytechnic State University San Luis Obispo. This document compiles the Baja SAE Semi-Active Suspension senior project team’s research and development of a semi-active suspension system for the Cal Poly Racing Baja SAE racecar. The goal is to design a system that adjusts the damping constant of the racecar’s spring-damper suspension while the vehicle is being driven in order to improve vehicle dynamics and driver comfort. None of the semi-active dampers that exist on …

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 …

R/C Baja: Drivetrain, Connor T. Donovan

All Undergraduate Projects

The Central Washington University Mechanical Engineering Technology Department hosts an annual R/C Baja competition in which R/C cars fabricated by student teams are put through a series of courses and tests to determine which team's vehicle is best. The goal of this project was to create a functioning drivetrain that conveys power from the battery to the wheels and provides control of the vehicle. A list of requirements for the drivetrain was created to ensure that the vehicle will not only function, but that it will actually succeed in the competition. These requirements included that the vehicle must achieve a …

Jcati Carbon Fiber Shredder 2022, Parker Sudderth

All Undergraduate Projects

This project is a potential solution to keep the carbon fiber waste from airplane manufacturing to a minimum, sponsored by the Joint Center for Aerospace Technology Innovation (JCATI). The design and assembly will be scalable for future industry application. The overall design of the whole carbon fiber recycler consists of a crusher, shredder, and oven. This report is on the caron fiber shredder module. The shredder is tasked with being able to shred the delaminated carbon fiber scrap that directly comes from the crusher. The operation must produce shreds in the proper size to be gathered and delivered to the …

Generative Adversarial Networks For Extrapolation Of Corrosion In Automobile Images, Andre Von Zuben

Electronic Theses and Dissertations, 2020-2023

Deep learning has shown success in several applications involving pattern recognition, expert systems, and scientific discovery. However, existing methods struggle with industrial applications, which are often challenged by non-ideal datasets. In many cases, the datasets are small, poorly labeled, noisy, or have unbalanced class distribution or any combination of such problems. In this Master's research, we propose a generative adversarial network (GAN) strategy that is able to circumvent limitations imposed by tiny datasets. As a case study, we use the extrapolation of corrosion in automobiles and feed our deep learning framework with only a few dozen images instead of the …

Modeling Human Control Behavior In Command-Following Tasks, Sajad Koushkbaghi

Theses and Dissertations--Mechanical and Aerospace Engineering

Humans interact with a variety of complex dynamic systems on a daily basis. However, they are often the lesser understood component of human-in-the-loop (HITL) systems. In this dissertation, we present the results of two HITL experiments to investigate the control strategies that humans use when performing command-following tasks. The first experiment is designed to investigate the control strategies that humans use to interact with nonlinear dynamic systems. Two groups of human subjects interact with a dynamic system and perform a command-following task. One group interacts with a linear time-invariant (LTI) dynamic system and the other group interacts with a Wiener …

Formation Control With Bounded Controls And Collision Avoidance: Theory And Application To Quadrotor Unmanned Air Vehicles, Zachary S. Lippay

Theses and Dissertations--Mechanical and Aerospace Engineering

This dissertation presents new results on multi-agent formation control and applies the new control algorithms to quadrotor unmanned air vehicles. First, this dissertation presents a formation control algorithm for double-integrator agents, where the formation is time varying and the agents’ controls satisfy a priori bounds (e.g., the controls accommodate actuator saturation). The main analytic results provide sufficient conditions such that all agents converge to the desired time-varying relative positions with one another and the leader, and have a priori bounded controls (if applicable). We also present results from rotorcraft experiments that demonstrate the algorithm with time-varying formations and bounded controls. …

The Effects Of Reference-Command Preview On The Strategies That Humans Use In Command-Following Tasks, Amelia J. S. Sheffler

Theses and Dissertations--Mechanical and Aerospace Engineering

This thesis presents results from an experiment in which 22 human subjects each interact with a dynamic system 40 times over a one-week period. For each interaction, a subject performs a command-following task, where the reference command is the same for all 22 subjects but different on each trial. The subjects are divided into 2 groups of 11 subjects. One group performs the command-following task without reference-command preview. The other group is provided with 1-s preview of the reference command. The experimental results are used to examine the effects of reference-command preview. For the group with 1-s reference-command preview, the …

Small-Satellite Attitude Control Using Sinusoidal Actuator Motion: Experiments On The International Space Station, K. Ryan Lush

Theses and Dissertations--Mechanical and Aerospace Engineering

In this work, we design, build, and test two 1.25U CubeSats. These small satellites were deployed on the International Space Station to perform attitude control experiments in microgravity. These CubeSats use an oscillating-mass actuation system for attitude control as opposed to traditional flywheels. Each CubeSat uses 3 pairs of servomotors to oscillate masses about 3 orthogonal axes. The servomotors have strict rotational stroke limits. Thus, they cannot spin continually. To oscillate each pair of masses, the angle of each servomotor is commanded using signals that are continuous and piecewise sinusoidal with amplitudes that do not violate the servomotor stroke constraints. …

Experimental Comparison Of Two Sampled-Data Adaptive Control Algorithms For Rejecting Sinusoidal Disturbances, William Grayson Woods

Theses and Dissertations--Mechanical and Aerospace Engineering

We review two adaptive control algorithms that address the problem of rejecting sinusoids with known frequencies that act on an unknown asymptotically stable linear time-invariant system. We present modifications to the algorithms that address the problems of sensor noise and actuator saturation. We demonstrate the effectiveness of the algorithms and compare the performance of the algorithms via numerical simulation and experimental testing.