Matching Items (14)
Description
Active flow control for airfoil designs has been researched for the past few decades. This has been achieved through steady blowing, pulsed blowing, synthetic jets, and plasma jets. These techniques have been applied to both single and dual jet configurations. This technology was examined for a wind turbine blade application so that lift and drag can be altered without needing a mechanical flap. Research was completed to also allow for thicker airfoils with more blunt trailing edges that result in the higher structural strength needed for large, heavy wind turbine blades without the negative aerodynamic effects such as boundary layer separation. This research tested steady blowing in a dual jet configuration for the S830 airfoil from the National Renewable Energy Laboratory (NREL) database of airfoils. Computational Fluid Dynamics was used in the software Ansys Fluent. Calculations were completed for a modified S830 airfoil with a rounded trailing edge surface at momentum coefficients of 0.01 for the lower jet and 0.1, 0.12, and 0.14 for the upper jet. These results were then compared to the original S830 results for the lift over drag efficiency. The design with momentum coefficients of 0.12 for the upper surface resulted in the highest increase in efficiency of 53% at an angle of attack of 12 degrees. At this momentum coefficient, the angle of attack where zero lift occurred was at -8.62 degrees, compared to the case with no blowing at -1.90 degrees. From previous research and research completed in this thesis it was concluded that active flow control is an effective technique to improve wind turbine energy collection.
ContributorsStapleton, Paige (Author) / Mertz, Benjamin (Thesis director) / Herrmann, Marcus (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Winglets and wingtip structures have been prominent in commercial aircraft design in the past few decades. These designs are known to reduce the induced drag on an aircraft wing, thus increasing its overall fuel efficiency. Several different winglet designs exist, and little reason is offered as to why different winglet designs are used in practice on different aircraft, especially those of variable range. This research tests existing winglets (no winglet, raked winglet, flat plate winglet, blended winglet, and wingtip fence) on a span-constrained wing planform design both computationally and in the wind tunnel. While computational tests using a vortex lattice code indicate that the wingtip fence minimizes induced drag and maximizes lift to drag ratio in most cases, wind tunnel tests show that at different lift coefficients and angles of attack, the raked winglet and blended winglet optimize the aerodynamic efficiency at incompressible flow velocities. Applying the wing aerodynamic data to existing variable range commercial aircraft, mission performance analysis is run on a Bombardier CRJ200, Airbus A320, and Airbus A340-300. By comparing flight lift coefficients in cruise for these aircraft to the lift coefficients at which winglets minimize drag in compressible flows, optimal winglet designs are chosen. It is found that the short range CRJ200 is best equipped with a flat plate or blended winglet, the medium range A320 can reduce drag with either a wingtip fence, raked winglet, or blended winglet, and the long range A340 performs best with a flat plate, blended, or raked winglet. Overall, despite the discrepancy in winglet selection depending on which experimental results are used, it is clear that addition of a winglet to a span-constrained wing is beneficial in that it reduces induced drag and therefore increases overall fuel efficiency.
ContributorsOremland, Joshua Elan (Author) / Wells, Valana (Thesis director) / Mertz, Benjamin (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Materials Science and Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
Engineers spend several years studying intense technical details of the processes that shape our world, yet few are exposed to classes addressing social behaviors or issues. Engineering culture creates specific barriers to addressing social science issues, such as unconscious bias, within engineering classrooms. I developed a curriculum that uses optical illusions, Legos, and the instructor's vulnerability to tackle unconscious bias in a way that addresses the barriers in engineering culture that prevent engineers from learning social science issues. Unconscious bias has documented long-term negative impacts on success and personal development, even in engineering environments. Creating a module in engineering education that addresses unconscious bias with the aim of reducing the negative effects of bias would benefit developing engineers by improving product development and team diversity. Engineering culture fosters disengagement with social issues through three pillars: depoliticization, technical/social dualism, and meritocracy. The developed curriculum uses optical illusions and Legos as proxies to start discussions about unconscious bias. The proxies allow engineers to explore their own biases without running into one of the pillars of disengagement that limits the engineer's willingness to discuss social issues. The curriculum was implemented in the Fall of 2017 in an upper-division engineering classroom as a professional communication module. The module received qualitatively positive feedback from fellow instructors and students. The curriculum was only implemented once by the author, but future implementations should be done with a different instructor and using quantitative data to measure if the learning objectives were achieved. Appendix A of the paper contains a lesson plan of the module that could be implemented by other instructors.
ContributorsLauber, Emily Anne (Author) / Wernimont, Jacqueline (Thesis director) / Mertz, Benjamin (Committee member) / Civil, Environmental and Sustainable Engineering Programs (Contributor) / College of Integrative Sciences and Arts (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
Carbon emissions have become a major concern since the turn of the century. This has increased the demand of hybrid vehicles in United States market. Hence, there is a need to make these vehicles more efficient. This thesis focuses on creating a thermal model that could be used for optimization of these vehicles. The project was accomplished in collaboration with EcoCar3, and the temperature data obtained from the model was compared with the experimental temperature data gathered from EcoCar's testing of the vehicle they built. The data obtained through this study demonstrates that the model was accurately able to predict thermal behavior of the electric motor and the high-voltage batteries in the vehicle. Therefore, this model could be used for optimization of the powertrain in a hybrid vehicle.
ContributorsMuthuvenkatesh, Nikhil (Author) / Mayyas, Abdel (Thesis director) / Patel, Jay (Committee member) / W.P. Carey School of Business (Contributor) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
This study analyzes mechanical properties of additively manufactured plastic materials produced in a conventional 3D printer. This topic has generally been studied in controlled scenarios, and this study aims to reflect the properties seen by consumers. Layered prints are inherently anisotropic due to the direction of the layers and associated weaknesses or stress concentrators. Thus, the ultimate strength and elastic modulus of plastic specimens produced using default settings are compared based on print orientation angle, and trends are observed. When a specimen is parallel to the build plate, it tends to have ultimate strength and elastic modulus near the published bulk values of 13.2MPa and 404-710MPa, but these values tend to decrease as the print angle increases.
ContributorsGarry, Allan Edward (Author) / Patel, Jay (Thesis director) / Mertz, Benjamin (Committee member) / School of Mathematical and Statistical Sciences (Contributor) / Mechanical and Aerospace Engineering Program (Contributor) / Materials Science and 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
In today’s day and age, the use of automated technology is becoming increasingly prevalent. Throughout the aerospace industry, we see the use of automated systems in manufacturing, testing, and, progressively, in design. This thesis focuses on the idea of automated structural design that can be directly coupled with parametric Computer-Aided Drafting (CAD) and used to support aircraft conceptual design. This idea has been around for many years; however, with the advancement of CAD technology, it is becoming more realistic. Having the ability to input design parameters, analyze the structure, and produce a basic CAD model not only saves time in the design process but provides an excellent platform to communicate ideas. The user has the ability to change parameters and quickly determine the effect on the structure. Coupling this idea with automated parametric CAD provides visual verification and a platform to export into Finite Element Analysis (FEA) for further verification.
ContributorsAnderson, Benjamin Kyle (Author) / Takahashi, Timothy (Thesis advisor) / Bolukbasi, Akif (Committee member) / Patel, Jay (Committee member) / Arizona State University (Publisher)
Created2017
Description
In this study, a scissor jack was structurally analyzed and compared to a FEA model to study the structure of the jack. the system was simplified to a 2D system, and one of the truss members was analyzed for yielding, fatigue, and buckling.
ContributorsLedalla, Aishwarya (Author) / Kosaraju, Srinivas (Thesis director) / Patel, Jay (Committee member) / Mechanical and Aerospace Engineering Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description
Concurrency bugs are one of the most notorious software bugs and are very difficult to manifest. Significant work has been done on detection of atomicity violations bugs for high performance systems but there is not much work related to detect these bugs for embedded systems. Although criteria to claim existence of bugs remains same, approach changes a bit for embedded systems. The main focus of this research is to develop a systemic methodology to address the issue from embedded systems perspective. A framework is developed which predicts the access interleaving patterns that may violate atomicity using memory references of shared variables and provides support to force and analyze these schedules for any output change, system fault or change in execution path.
ContributorsPatel, Jay (Author) / Lee, Yann-Hang (Thesis advisor) / Ren, Fengbo (Committee member) / Srivastava, Aviral (Committee member) / Arizona State University (Publisher)
Created2016
Description
Essential knowledge of Co-continuous composite material properties are explored in this thesis. Mechanical characterization of these materials gives a detailed outlook to use them in design, manufacture and tailor make the products.
Soft and hard polymer materials have extensive properties individually, but when combined to make a single structure, they give an exceptional combination of properties. In this study, Polymer materials used are in the form of Co-Continuous structures (i.e., both soft and hard polymers are continuous throughout the microstructure) fabricated into several microstructures namely, Simple Cubic (SC), Body-Centered Cubic (BCC) and Face Centered Cubic (FCC) shapes. An experimental process is designed and fine-tuned from existing methods to understand and record the mechanical response of these co-continuous polymers. Experimental testing is used to gather detailed information about several constituencies namely stress behavior and damage progression. A 3D imaging technique, Microtomography is used to visualize damage initiation and progression in the sample. Variations in energy absorption, fracture initiation and damage propagation in samples are observed and correlated analysis is performed to provide a logical explanation. Comparative studies are performed as well for different structures.
Based on the Knowledge gained from the above study on co-continuous polymer composites, several conclusions are drawn, and future work directions are suggested.
Soft and hard polymer materials have extensive properties individually, but when combined to make a single structure, they give an exceptional combination of properties. In this study, Polymer materials used are in the form of Co-Continuous structures (i.e., both soft and hard polymers are continuous throughout the microstructure) fabricated into several microstructures namely, Simple Cubic (SC), Body-Centered Cubic (BCC) and Face Centered Cubic (FCC) shapes. An experimental process is designed and fine-tuned from existing methods to understand and record the mechanical response of these co-continuous polymers. Experimental testing is used to gather detailed information about several constituencies namely stress behavior and damage progression. A 3D imaging technique, Microtomography is used to visualize damage initiation and progression in the sample. Variations in energy absorption, fracture initiation and damage propagation in samples are observed and correlated analysis is performed to provide a logical explanation. Comparative studies are performed as well for different structures.
Based on the Knowledge gained from the above study on co-continuous polymer composites, several conclusions are drawn, and future work directions are suggested.
ContributorsVARAKANTHAM, MADHAVA REDDY (Author) / Yongming, Liu (Thesis advisor) / Patel, Jay (Committee member) / Hanqing, Jiang (Committee member) / Arizona State University (Publisher)
Created2019