Educational Software Based on System Dynamics

Description

This thesis explores the potential for software to act as an educational experience for engineers who are learning system dynamics and controls. The specific focus is a spring-mass-damper system. First, a brief introduction of the spring-mass-damper system is given, followed

This thesis explores the potential for software to act as an educational experience for engineers who are learning system dynamics and controls. The specific focus is a spring-mass-damper system. First, a brief introduction of the spring-mass-damper system is given, followed by a review of the background and prior work concerning this topic. Then, the methodology and main approaches of the system are explained, as well as a more technical overview of the program. Lastly, a conclusion and discussion of potential future work is covered. The project was found to be useful by several engineers who tested it. While there is still plenty of functionality to add, it is a promising first attempt at teaching engineers through software development.

Date Created
2021-05
Agent

Unique Design Discoveries for a Modern Mach 1.3 Airliner Including Anomalies in the Shock Wave Formation Along a Highly Swept Blunt Leading Edge Wing

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Description
The process of designing any real world blunt leading-edge wing is tedious andinvolves hundreds, if not thousands, of design iterations to narrow down a single design.
Add in the complexities of supersonic flow and the challenge increases exponentially.
One possible, and often

The process of designing any real world blunt leading-edge wing is tedious andinvolves hundreds, if not thousands, of design iterations to narrow down a single design.
Add in the complexities of supersonic flow and the challenge increases exponentially.
One possible, and often common, pathway for this design is to jump straight into detailed
volume grid computational fluid dynamics (CFD), in which the physics of supersonic
flow are modeled directly but at a high computational cost and thus an incredibly long
design process. Classical aerodynamics experts have published work describing a process
which can be followed which might bypass the need for detailed CFD altogether.

This work outlines how successfully a simple vortex lattice panel method CFDcode can be used in the design process for a Mach 1.3 cruise speed airline wing concept.
Specifically, the success of the wing design is measured in its ability to operate subcritically (i.e. free of shock waves) even in a free stream flow which is faster than the
speed of sound. By using a modified version of Simple Sweep Theory, design goals are
described almost entirely based on defined critical pressure coefficients and critical Mach
numbers. The marks of a well-designed wing are discussed in depth and how these traits
will naturally lend themselves to a well-suited supersonic wing.

Unfortunately, inconsistencies with the published work are revealed by detailedCFD validation runs to be extensive and large in magnitude. These inconsistencies likely
have roots in several concepts related to supersonic compressible flow which are
explored in detail. The conclusion is made that the theory referenced in this work by the
classical aerodynamicists is incorrect and/or incomplete. The true explanation for the
perplexing shock wave phenomenon observed certainly lies in some convolution of the
factors discussed in this thesis. Much work can still be performed in the way of creating
an empirical model for shock wave formation across a highly swept wing with blunt
leading-edge airfoils.
Date Created
2020
Agent

Mathematical Modeling of Air Bladders for use as an Orthotic

Description
Due to the Human foot constantly growing at a rapid pace, typical gel and mold orthotics quickly become ineffective as they no longer fit the foot properly. In pediatric patients, this situation is even more pronounced as their feet change

Due to the Human foot constantly growing at a rapid pace, typical gel and mold orthotics quickly become ineffective as they no longer fit the foot properly. In pediatric patients, this situation is even more pronounced as their feet change geometry at an even more rapid rate. This project consists of designing an adjustable sizing Pediatric Orthotic for use in children as well as adult patient’s shoes to provide better foot support than not using one at all, or for that matter an inappropriately sized orthotic. This idea incorporates multiple air bladders that can hold pressure and adjust shape as is necessary to best accommodate the patient’s foot geometry to reduce the deformation and average stress presented within the foot. Results will be obtained by running simulation models of these phenomena in MATLAB as well as Ansys softwares. From the results, by incorporating two bladders into the middle arch of a ‘control’ patient who has a perfectly symmetric arch, maximum deformation of the foot was reduced by approximately 17%. Under this same scenario, average stress in the foot dropped by approximately 13%. In a more abnormal ‘experimental’ case, of a largely asymmetric arch, it was found that max deformation and average stress in the foot dropped by 21% and 17% respectively. This leads to the conclusion that incorporating this design will indeed lower the stress and fulfill the requirement of an orthotic while also being a removable and adjustable air bladder to fulfill the adjustability constraint.
Date Created
2020-12
Agent

Thermal Analysis of Preliminary Design of Pulsed Plasma Thruster for Multi-Axis CubeSat Attitude Control Applications

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Description
Smallsats such as CubeSats have a variety of growing applications in low Earth orbit (LEO), near Earth orbit (NEO), and deep space environments across communications, imaging, and more. Such applications have tight pointing requirements and thus an accompanying need for

Smallsats such as CubeSats have a variety of growing applications in low Earth orbit (LEO), near Earth orbit (NEO), and deep space environments across communications, imaging, and more. Such applications have tight pointing requirements and thus an accompanying need for attitude control systems (ACS) with finer pointing capabilities and longer lifetimes. Current systems such as magnetorquers and reaction wheels have notable limitations. Magnetorquers lose applicability for many deep space applications while the latter is dependent on moving components and cannot be operated independently due to momentum saturation among other limitations. Micro-Pulsed Plasma Thrusters (μPPTs) can be designed for multi-axis control in space. The use of solid Teflon (PTFE) propellant to produce a controllably small impulse within the thrusters can enable increased fine pointing accuracy and precision. In this paper, a preliminary design of an 8-thruster set of breech-fed μPPTs is analyzed through mechanical simulation tools to address challenges posed by miniaturization into a 1U module. Mechanical challenges of miniaturizing a μPPT module are particularly driven by the volume constraint and the associated appropriate mass. Thermal analysis performed using C&R Thermal Desktop, addresses the thermal environment for various use cases, individual component heating, as well as heat transfer through the module. This directly informs component layout recommendations and thermal controls based upon maintaining operational temperature ranges for various use cases. This model as well as fabrication considerations inform material selections for various structures in the preliminary μPPT design. In this paper I will discuss the overall design of the PPT model that has been configured here at Arizona State University by the Sun Devil Satellite Laboratory. I will then discuss the findings of my thermal analysis that was performed using Thermal Desktop.
Date Created
2020-05
Agent

Controlling Exhaust Pipe Temperatures: An Environmental Concern

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Description
The temperature of exhaust pipes can be dangerous in dry areas where there is a lot of brush. The temperatures of exhaust pipes can reach a high enough temperature to start a fire if touching the dry brush, which ignites

The temperature of exhaust pipes can be dangerous in dry areas where there is a lot of brush. The temperatures of exhaust pipes can reach a high enough temperature to start a fire if touching the dry brush, which ignites around 300°C. The goal of this project was to explore different techniques to limit the possibility of these brush fires. Specifically, different methods were explored to reduce the temperature of the pipe that would be contacting the brush. Fires can begin within seconds of contacting the hot exhaust pipes [10]. This experiment found that of the three options tested: exhaust wrap, heat sink with thermoelectric devices, and high temperature paint, adding a heat shield/sink is the best way to limit the high temperatures from igniting the brush. There was a cooling difference of nearly 100°C when a heat shield/sink was added to the bare pipe. The additional thermal mass as well as the finned heat sinks attached to the heat sink helped dissipate the heat from the pipe and release the waste heat into the surroundings. The increase in surface area in correspondence with forced convection from the surrounding air lowered the temperature of the metal in contact with the dry brush.
Date Created
2020-05
Agent