Matching Items (433)
Filtering by
- Creators: Mechanical and Aerospace Engineering Program
- Member of: Theses and Dissertations
Description
Formula SAE is a student design competition where students design and fabricate a formula-style racecar to race in a series of events against schools from around the world. It gives students of all majors the ability to use classroom theory and knowledge in a real world application. The general guidelines for the prototype racecars is for the students to use four-stroke, Otto cycle piston engines with a displacement of no greater than 610cc. A 20mm air restrictor downstream the throttle limits the power of the engines to under 100 horsepower. A 178-page rulebook outlines the remaining restrictions as they apply to the various vehicle systems: vehicle dynamics, driver interface, aerodynamics, and engine. Vehicle dynamics is simply the study of the forces which affect wheeled vehicles in motion. Its primary components are the chassis and suspension system. Driver interface controls everything that the driver interacts with including steering wheel, seat, pedals, and shifter. Aerodynamics refers to the outside skin of the vehicle which controls the amount of drag and downforce on the vehicle. Finally, the engine consists of the air intake, engine block, cooling system, and the exhaust. The exhaust is one of the most important pieces of an engine that is often overlooked in racecar design. The purpose of the exhaust is to control the removal of the combusted air-fuel mixture from the engine cylinders. The exhaust as well as the intake is important because they govern the flow into and out of the engine's cylinders (Heywood 231). They are especially important in racecar design because they have a great impact on the power produced by an engine. The higher the airflow through the cylinders, the larger amount of fuel that can be burned and consequently, the greater amount of power the engine can produce. In the exhaust system, higher airflow is governed by several factors. A good exhaust design gives and engine a higher volumetric efficiency through the exhaust scavenging effect. Volumetric efficiency is also affected by frictional losses. In addition, the system should ideally be lightweight, and easily manufacturable. Arizona State University's Formula SAE racecar uses a Honda F4i Engine from a CBR 600 motorcycle. It is a four cylinder Otto cycle engine with a 600cc displacement. An ideal or tuned exhaust system for this car would maximize the negative gauge pressure during valve overlap at the ideal operating rpm. Based on the typical track layout for the Formula SAE design series, an ideal exhaust system would be optimized for 7500 rpm and work well in the range
ContributorsButterfield, Brandon Michael (Author) / Huang, Huei-Ping (Thesis director) / Trimble, Steven (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Materials Science and Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
One of the leading concerns regarding the commercial and military applications of rotary wing powered vehicles is the issue of blade-vortex interaction (BVI) noise occurring during forward descent. This impulsive noise-generating phenomenon occurs due to the close proximity and interference between the main rotor blades and the wake vortices generated by the rotor blades from previous revolutions. Throughout the descent phase of a helicopter in forward flight, the rotating blades pass through these induced vortices, thus generating an impulsive "slap" noise that is characteristic of the common sound associated with helicopter flight among the general population. Therefore, parameterization of the variables of interest that affect BVI noise generation will allow for thorough analysis of the origins of the noise and open pathways for innovation that may offer significant improvements in acoustic performance. Gaining an understanding of the factors that govern the intensity of the BVI acoustic signature provides a strong analytical and experimental basis for enhanced rotor blade design.
ContributorsAhlf, Rick James (Author) / Dahm, Werner (Thesis director) / Wells, Valana (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / School of Sustainability (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
In real world applications, materials undergo a simultaneous combination of tension, compression, and torsion as a result of high velocity impact. The split Hopkinson pressure bar (SHPB) is an effective tool for analyzing stress-strain response of materials at high strain rates but currently little can be done to produce a synchronized combination of these varying impacts. This research focuses on fabricating a flange which will be mounted on the incident bar of a SHPB and struck perpendicularly by a pneumatically driven striker thus allowing for torsion without interfering with the simultaneous compression or tension. Analytical calculations are done to determine size specifications of the flange to protect against yielding or failure. Based on these results and other design considerations, the flange and a complementary incident bar are created. Timing can then be established such that the waves impact the specimen at the same time causing simultaneous loading of a specimen. This thesis allows research at Arizona State University to individually incorporate all uniaxial deformation modes (tension, compression, and torsion) at high strain rates as well as combining either of the first two modes with torsion. Introduction of torsion will expand the testing capabilities of the SHPB at ASU and allow for more in depth analysis of the mechanical behavior of materials under impact loading. Combining torsion with tension or compression will promote analysis of a material's adherence to the Von Mises failure criterion. This greater understanding of material behavior can be implemented into models and simulations thereby improving the accuracy with which engineers can design new structures.
ContributorsVotroubek, Edward Daniel (Author) / Solanki, Kiran (Thesis director) / Oswald, Jay (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
As part of a United States-Australian Solar Energy Collaboration on a Micro Urban Solar Integrated Concentrator project, the purpose of the research was to design and build a bench-top apparatus of a solar power concentrator thermal storage unit. This prototype would serve to be a test apparatus for testing multiple thermal storage mediums and heat transfer fluids for verification and optimization of the larger system. The initial temperature range for the system to test a wide variety of thermal storage mediums was 100°C to 400°C. As for the thermal storage volume it was decided that the team would need to test volumes of about 100 mL. These design parameters later changed to a smaller range for the initial prototype apparatus. This temperature range was decided to be 210°C to 240°C using tin as a phase change material (PCM). It was also decided a low temperature (<100°C) test using paraffin as the PCM would be beneficial for troubleshooting purposes.
ContributorsLee, William John (Author) / Phelan, Patrick (Thesis director) / Wang, Robert (Committee member) / Barrett, The Honors College (Contributor) / Mechanical and Aerospace Engineering Program (Contributor) / School of International Letters and Cultures (Contributor)
Created2015-05
Description
In order to better understand the physical properties of polyethylene, an extremely common plastic used mostly in packaging, many scientists and engineers use olecular dynamics. To reduce the computational expense associated with traditional atomistic molecular dynamics, coarse-grained molecular dynamics is often used. Coarse-grained molecular dynamics groups multiple atoms into single beads, reducing the number of degrees of freedom in a system and eliminating smaller atoms with faster kinematics. However, even coarse-grained methods have their limitations, one of which is timestep duration, which is limited by the maximum vibrational frequency in the coarse-grained system. To study this limitation, a coarse-grained model of polyethylene was created such that every C 2 H 4 unit was replaced with a bead. Coarse-grained potentials for bond-stretching, bond-bending, and non-bonded interaction were generated using the iterative Boltzmann inversion method, which matches coarse-grained distribution functions to atomistic distribution functions. After the creation of the model, the coarse-grained potentials were rescaled by a constant so that they were less stiff, decreasing the maximum vibrational frequency of the system. It is found that by diminishing the bond-stretching potential to 6.25% of its original value, the maximum stable timestep can be increased 85% over that of the unmodified potential functions. The results of this work suggest that it may be possible to simulate lengthy processes, such as the crystallization of polyethylene, in less time with adjusted coarse-grained potentials. Additionally, the large discrepancies in the speed of bond-stretching, bond-bending, and non- bonded interaction dynamics suggest that a multi-timestep method may be worth investigating in future work.
ContributorsWiles, Christian Scott (Author) / Oswald, Jay (Thesis director) / Dai, Lenore (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2015-12
Description
The goal of this thesis project was to build an understanding of supersonic projectile dynamics through the creation of a trajectory model that incorporates several different aerodynamic concepts and builds a criteria for the stability of a projectile. This was done iteratively where the model was built from a foundation of kinematics with various aerodynamic principles being added incrementally. The primary aerodynamic principle that influenced the trajectory of the projectile was in the coefficient of drag. The drag coefficient was split into three primary components: the form drag, skin friction drag, and base pressure drag. These together made up the core of the model, additional complexity served to increase the accuracy of the model and generalize to different projectile profiles.
ContributorsBlair, Martin (Co-author) / Armenta, Francisco (Co-author) / Takahashi, Timothy (Thesis director) / Herrmann, Marcus (Committee member) / Mechanical and Aerospace Engineering Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
This paper discusses the design of experimental setup and procedures to characterize polymethyl methylate (PMMA) at its glass transition temperature by studying its strain fields, process zone, and crack speed under different loading conditions. These loading conditions are different steady-state temperatures and initial crack lengths. Steady-state temperature testing uses a temperature control loop. Crack speed / resistivity testing is set up using a voltage drop method. From initial steady-state temperature testing, it was confirmed that the behavior of a PMMA sample becomes more ductile at higher temperatures, and that it is plausible for a crack process zone to be measured using DIC as temperature increases. From finite element simulations, it was validated that the crack speed is not constant relative to an initial crack length.
ContributorsKwan, Brandon (Author) / Oswald, Jay (Thesis director) / Hoover, Christian (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
Solar panels need to be both cost effective and environmentally friendly to compete with traditional energy forms. Photovoltaic recycling has the potential to mitigate the harm of waste, which is often landfilled, while putting material back into the manufacturing process. Out of many, three methods show much promise: Full Recovery End-of-Life Photovoltaic (FRELP), mechanical, and sintering-based recycling. FRELP recycling has quickly gained prominence in Europe and promises to fully recover the components in a solar cell. The mechanical method has produced high yields of valuable materials using basic and inexpensive processes. The sintering method has the potential to tap into a large market for feldspar. Using a levelized cost of electricity (LCOE) analysis, the three methods could be compared on an economic basis. This showed that the mechanical method is least expensive, and the sintering method is the most expensive. Using this model, all recycling methods are less cost effective than the control analysis without recycling. Sensitivity analyses were then done on the effect of the discount rate, capacity factor, and lifespan on the LCOE. These results showed that the change in capacity factor had the most significant effect on the levelized cost of electricity. A final sensitivity analysis was done based on the decreased installation and balance of systems costs in 2025. With a 55% decrease in these costs, the LCOE decreased by close to $0.03/kWh for each method. Based on these results, the cost of each recycling method would be a more considerable proportion of the overall LCOE of the solar farm.
ContributorsMeister, William Frederick (Author) / Goodnick, Stephen (Thesis director) / Phelan, Patrick (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
The project consists of steps that a Formula SAE team could take into developing their first carbon fiber monocoque chassis. The project is based on an interview with a successful team that has build carbon monocoques for the last several years. The project covers the steps into designing a carbon monocoque, including aspects that need to be highlighted in the design process as well as an outline of the overall rules and regulations regarding carbon fiber monocoques. The project also encompasses simple finite element analysis procedure that would introduce teams into carbon fiber composite sandwich analysis and its applications in racecar monocoques. The project also includes steps in manufacturing a carbon fiber monocoque beginning from methods to acquire necessary materials to the final process of de-molding the monocoque. The method has been used before from several FSAE teams, proving its viability. The goal is that through this report, teams could have an idea of where to start in developing their carbon monocoques and have a clear path to take on going from initial designs up until a final finished product.
ContributorsEhrke, Lawrence Herman (Co-author) / Andiyastika, Gede P. (Co-author) / Patel, Jay (Thesis director) / Middleton, James (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
The operating principles of bicycle drivetrains have remained largely static since the invention of the derailleur in 1905. A bicycle-specific Continuously Variable Transmission has the potential to eliminate many of these issues. This paper explores the current state of bicycle CVT technology, details the advantages and disadvantages of these designs, and analyzes the many human factors that play into their adoption. Finally, a conceptual design for a novel bicycle CVT is described, and a physical model is created to demonstrate the mechanical principles of operation.
ContributorsBurgard, Kyle (Author) / Singh, Anoop (Thesis director) / Trimble, Steven (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05