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- Creators: Barrett, The Honors College
Description
Aluminum alloys are ubiquitously used in almost all structural applications due to their high strength-to-weight ratio. Their superior mechanical performance can be attributed to complex dispersions of nanoscale intermetallic particles that precipitate out from the alloy’s solid solution and offer resistance to deformation. Although they have been extensively investigated in the last century, the traditional approaches employed in the past haven’t rendered an authoritative microstructural understanding in such materials. The effect of the precipitates’ inherent complex morphology and their three-dimensional (3D) spatial distribution on evolution and deformation behavior have often been precluded. In this study, for the first time, synchrotron-based hard X-ray nano-tomography has been implemented in Al-Cu alloys to measure growth kinetics of different nanoscale phases in 3D and reveal mechanistic insights behind some of the observed novel phase transformation reactions occurring at high temperatures. The experimental results were reconciled with coarsening models from the LSW theory to an unprecedented extent, thereby establishing a new paradigm for thermodynamic analysis of precipitate assemblies. By using a unique correlative approach, a non-destructive means of estimating precipitation-strengthening in such alloys has been introduced. Limitations of using existing mechanical strengthening models in such alloys have been discussed and a means to quantify individual contributions from different strengthening mechanisms has been established.
The current rapid pace of technological progress necessitates the demand for more resilient and high-performance alloys. To achieve this, a thorough understanding of the relationships between material properties and its structure is indispensable. To establish this correlation and achieve desired properties from structural alloys, microstructural response to mechanical stimuli needs to be understood in three-dimensions (3D). To that effect, in situ tests were conducted at the synchrotron (Advanced Photon Source) using Transmission X-Ray Microscopy as well as in a scanning electron microscope (SEM) to study real-time damage evolution in such alloys. Findings of precipitate size-dependent transition in deformation behavior from these tests have inspired a novel resilient aluminum alloy design.
The current rapid pace of technological progress necessitates the demand for more resilient and high-performance alloys. To achieve this, a thorough understanding of the relationships between material properties and its structure is indispensable. To establish this correlation and achieve desired properties from structural alloys, microstructural response to mechanical stimuli needs to be understood in three-dimensions (3D). To that effect, in situ tests were conducted at the synchrotron (Advanced Photon Source) using Transmission X-Ray Microscopy as well as in a scanning electron microscope (SEM) to study real-time damage evolution in such alloys. Findings of precipitate size-dependent transition in deformation behavior from these tests have inspired a novel resilient aluminum alloy design.
ContributorsKaira, Chandrashekara Shashank (Author) / Chawla, Nikhilesh (Thesis advisor) / Solanki, Kiran (Committee member) / Jiao, Yang (Committee member) / De Andrade, Vincent (Committee member) / Arizona State University (Publisher)
Created2017
Description
Interstitial impurity atoms can significantly alter the chemical and physical properties of the host material. Oxygen impurity in HCP titanium is known to have a considerable strengthening effect mainly through interactions with dislocations. To better understand such an effect, first the role of oxygen on various slip planes in titanium is examined using generalized stacking fault energies (GSFE) computed by the first principles calculations. It is shown that oxygen can significantly increase the energy barrier to dislocation motion on most of the studied slip planes. Then the Peierls-Nabbaro model is utilized in conjunction with the GSFE to estimate the Peierls stress ratios for different slip systems. Using such information along with a set of tension and compression experiments, the parameters of a continuum scale crystal plasticity model, namely CRSS values, are calibrated. Effect of oxygen content on the macroscopic stress-strain response is further investigated through experiments on oxygen-boosted samples at room temperature. It is demonstrated that the crystal plasticity model can very well capture the effect of oxygen content on the global response of the samples. It is also revealed that oxygen promotes the slip activity on the pyramidal planes.
The effect of oxygen impurity on titanium is further investigated under high cycle fatigue loading. For that purpose, a two-step hierarchical crystal plasticity for fatigue predictions is presented. Fatigue indicator parameter is used as the main driving force in an energy-based crack nucleation model. To calculate the FIPs, high-resolution full-field crystal plasticity simulations are carried out using a spectral solver. A nucleation model is proposed and calibrated by the fatigue experimental data for notched titanium samples with different oxygen contents and under two load ratios. Overall, it is shown that the presented approach is capable of predicting the high cycle fatigue nucleation time. Moreover, qualitative predictions of microstructurally small crack growth rates are provided. The multi-scale methodology presented here can be extended to other material systems to facilitate a better understanding of the fundamental deformation mechanisms, and to effectively implement such knowledge in mesoscale-macroscale investigations.
The effect of oxygen impurity on titanium is further investigated under high cycle fatigue loading. For that purpose, a two-step hierarchical crystal plasticity for fatigue predictions is presented. Fatigue indicator parameter is used as the main driving force in an energy-based crack nucleation model. To calculate the FIPs, high-resolution full-field crystal plasticity simulations are carried out using a spectral solver. A nucleation model is proposed and calibrated by the fatigue experimental data for notched titanium samples with different oxygen contents and under two load ratios. Overall, it is shown that the presented approach is capable of predicting the high cycle fatigue nucleation time. Moreover, qualitative predictions of microstructurally small crack growth rates are provided. The multi-scale methodology presented here can be extended to other material systems to facilitate a better understanding of the fundamental deformation mechanisms, and to effectively implement such knowledge in mesoscale-macroscale investigations.
ContributorsGholami Bazehhour, Benyamin (Author) / Solanki, Kiran N (Thesis advisor) / Liu, Yongming (Committee member) / Oswald, Jay J (Committee member) / Rajagopalan, Jagannathan (Committee member) / Jiao, Yang (Committee member) / Arizona State University (Publisher)
Created2018
Description
Advanced material systems refer to materials that are comprised of multiple traditional constituents but complex microstructure morphologies, which lead to their superior properties over conventional materials. This dissertation is motivated by the grand challenge in accelerating the design of advanced material systems through systematic optimization with respect to material microstructures or processing settings. While optimization techniques have mature applications to a large range of engineering systems, their application to material design meets unique challenges due to the high dimensionality of microstructures and the high costs in computing process-structure-property (PSP) mappings. The key to addressing these challenges is the learning of material representations and predictive PSP mappings while managing a small data acquisition budget. This dissertation thus focuses on developing learning mechanisms that leverage context-specific meta-data and physics-based theories. Two research tasks will be conducted: In the first, we develop a statistical generative model that learns to characterize high-dimensional microstructure samples using low-dimensional features. We improve the data efficiency of a variational autoencoder by introducing a morphology loss to the training. We demonstrate that the resultant microstructure generator is morphology-aware when trained on a small set of material samples, and can effectively constrain the microstructure space during material design. In the second task, we investigate an active learning mechanism where new samples are acquired based on their violation to a theory-driven constraint on the physics-based model. We demonstrate using a topology optimization case that while data acquisition through the physics-based model is often expensive (e.g., obtaining microstructures through simulation or optimization processes), the evaluation of the constraint can be far more affordable (e.g., checking whether a solution is optimal or equilibrium). We show that this theory-driven learning algorithm can lead to much improved learning efficiency and generalization performance when such constraints can be derived. The outcomes of this research is a better understanding of how physics knowledge about material systems can be integrated into machine learning frameworks, in order to achieve more cost-effective and reliable learning of material representations and predictive models, which are essential to accelerate computational material design.
ContributorsCang, Ruijin (Author) / Ren, Yi (Thesis advisor) / Liu, Yongming (Committee member) / Jiao, Yang (Committee member) / Nian, Qiong (Committee member) / Zhuang, Houlong (Committee member) / Arizona State University (Publisher)
Created2018
Description
The saxophone is privileged to have a wide variety of repertoire from contemporary composers. Due to its invention in the later half of the nineteenth century, it has no repertoire written by baroque composers, including Johann Sebastian Bach. There are several published arrangements of Bach’s three solo violin partitas including that of Ronald Caravan and Raaf Hekkema. These collections either do not present every movement of each of these three partitas, or they do not present them in their original keys. An advantage to arranging these works in their original keys is that saxophonists have the opportunity to learn more about the works by playing along with recordings of great violinists such as Itzhak Perlman and Hilary Hahn, something that would be very difficult to do if they were not in the original keys. In Ronald Caravan’s Bach for Solo Saxophone, Caravan includes a collection of many unaccompanied works by Bach for saxophone but does not include all of the movements from the three partitas and they are not in the original keys that Bach wrote for. In Raaf Hekkema’s Bach for Saxophone, Hekkema arranges the entirety of the three partitas, however they are not set in the original keys that Bach wrote for. In addition to these points, those collections do not provide information of the life of J.S. Bach, baroque performance practice, mechanics of the baroque violin, baroque dances, and advice on going about the mechanics of these pieces from a saxophonist’s perspective. This information is very useful to a young saxophonist who is trying to fully understand and perform Bach’s three solo violin partitas.
ContributorsSalazar, Nathan John (Author) / Creviston, Christopher (Thesis director) / Saucier, Catherine (Committee member) / School of Music (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
This thesis evaluates the viability of an original design for a cost-effective wheel-mounted dynamometer for road vehicles. The goal is to show whether or not a device that generates torque and horsepower curves by processing accelerometer data collected at the edge of a wheel can yield results that are comparable to results obtained using a conventional chassis dynamometer. Torque curves were generated via the experimental method under a variety of circumstances and also obtained professionally by a precision engine testing company. Metrics were created to measure the precision of the experimental device's ability to consistently generate torque curves and also to compare the similarity of these curves to the professionally obtained torque curves. The results revealed that although the test device does not quite provide the same level of precision as the professional chassis dynamometer, it does create torque curves that closely resemble the chassis dynamometer torque curves and exhibit a consistency between trials comparable to the professional results, even on rough road surfaces. The results suggest that the test device provides enough accuracy and precision to satisfy the needs of most consumers interested in measuring their vehicle's engine performance but probably lacks the level of accuracy and precision needed to appeal to professionals.
ContributorsKing, Michael (Author) / Ren, Yi (Thesis director) / Spanias, Andreas (Committee member) / School of Mathematical and Statistical Sciences (Contributor) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
This research project will test the structural properties of a 3D printed origami inspired structure and compare them with a standard honeycomb structure. The models have equal face areas, model heights, and overall volume but wall thicknesses will be different. Stress-deformation curves were developed from static loading testing. The area under these curves was used to calculate the toughness of the structures. These curves were analyzed to see which structures take more load and which deform more before fracture. Furthermore, graphs of the Stress-Strain plots were produced. Using 3-D printed parts in tough resin printed with a Stereolithography (SLA) printer, the origami inspired structure withstood a larger load, produced a larger toughness and deformed more before failure than the equivalent honeycomb structure.
ContributorsMcGregor, Alexander (Author) / Jiang, Hanqing (Thesis director) / Kingsbury, Dallas (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
This creative project explores the concept of how music is like a language and how, as a teacher, I plan to enforce this concept through my teaching. The aim of this project is to highlight the importance of completing research and acquiring knowledge of aspects, such as the composer's life, historical background and literary references, when learning a piece of music. Through this project, I address connections between the brain and music pertaining to memorization, the components of language, the similarities between language and music, the role of the teacher and the development of a "toolbox" of knowledge for studying a piece of music. I present my own research on Schumann's Novelette Op. 21, No. 8 in f-sharp minor as well as my own experiences of learning the piece to demonstrate an example of the process and discoveries I hope my students will make in their own studies of repertoire.
ContributorsLee, Kara Jia-Shan (Author) / Pagano, Caio (Thesis director) / Creviston, Hannah (Committee member) / Division of Teacher Preparation (Contributor) / School of Music (Contributor) / Barrett, The Honors College (Contributor)
Created2017-12
Description
The SolarSPELL is an offline, ruggedized, digital library, created by Dr. Laura Hosman for the U.S. Peace Corps. It has thousands of pieces of educational content that can be accessed through a self-contained Wi-Fi hotspot on the device itself. Currently, there are more than 200 deployed in several Pacific Island nations. After visiting one of these nations, Tonga, in December of 2016, I learned that almost all of the Peace Corps volunteers stationed around the Pacific Islands suffered from a lack of resources due to a variety of reasons. While the SolarSPELL helps to remedy that, the device is lacking classroom activities and resources for creative work and educational drama. Furthermore, for many students in these environments, schools are for learning information and producing high scores on exams, not for learning about creative strengths and identity. After researching curriculum development and the use of drama in an educational setting, I compiled over 50 pieces of content to include on the SolarSPELL involving art, drama, music, movement, and most importantly, imagination. These resources will allow Peace Corps volunteers to explore additional ways to teach English in their schools, while also creating a classroom environment that allows for creative expression. All the content is compiled into one folder as "Teaching Resources", and is then broken down into seven sub- categories. In the first sub-category, Art Projects, there is a collection of several hands-on projects, many of which involve recyclable or readily available materials. These projects will allow for a greater understanding of conservation and "green" living, concepts that are crucial to the stability of these island nations. The next 5 categories are Drama Readings, Music, Movement, and Video, Group Exercises, Creative Writing, and Worksheets. The second sub- category is a collection of beginner-level "Reader's Theater" scripts. The third sub-category involves music and video to engage students in movement activities. The fourth sub-category is a compilation of group games and activities to help students express themselves and learn social skills. The fifth sub-category includes a collection of activities such as fill-in-the-blank story worksheets and journal prompts which will aid in creative thinking and the practice of the English language. The sixth sub-category involves a collection of worksheets that mainly focus on self-reflection and identity. The seventh and final sub-category, Content Guide and Information, works to explain the benefits of using of drama and creative play in the classroom, as well as strategies teachers can implement in order to further engage their students in dramatic learning and play. Overall, these pieces of content are meant to be used as resources for the Peace Corps volunteers in order to provide alternative ways to practice reading, writing, and speaking the English language, a critical part of education in the Pacific Islands.
ContributorsTaylor, Amanda Nicole (Author) / Hosman, Laura (Thesis director) / McAvoy, Mary (Committee member) / School of Film, Dance and Theatre (Contributor) / Division of Teacher Preparation (Contributor) / Barrett, The Honors College (Contributor) / School for the Future of Innovation in Society (Contributor)
Created2017-12
Description
This creative project thesis involves electronic music composition and production, and it uses some elements of algorithmic music composition (through recurrent neural networks). Algorithmic composition techniques are used here as a tool in composing the pieces, but are not the main focus. Thematically, this project explores the analogy between artificial neural networks and neural activity in the brain. This project consists of three short pieces, each exploring these concept in different ways.
ContributorsKarpur, Ajay (Author) / Suzuki, Kotoka (Thesis director) / Ingalls, Todd (Committee member) / Electrical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Musical interpretation is challenging when one's goal is to evoke an emotional response from an audience. In order to develop a well-informed interpretation of Mozart's Fantasia in D minor K. 397, a study was conducted on the historical background of the piece and various performances by well-regarded performers. Fantasias are written works, but improvisatory by nature. Mozart's fantasias were influenced by C. P. E. Bach's, which included sudden changes in emotion. An Emil Gilels performance provided a classically trained approach, while Mitsuko Uchida's performance provided an emotional approach. Colin Tilney and John Irving performances elucidated the sound of the instruments that Mozart would have been composing with. Altogether, the research culminated in an interpretation of the D minor Fantasia that endeavored to capture the essence of fantasy, improvisation and emotion.
ContributorsMo, Gina Nan (Author) / Emmery, Laura (Thesis director) / Creviston, Hannah (Committee member) / Department of Psychology (Contributor) / School of International Letters and Cultures (Contributor) / School of Molecular Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05