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- All Subjects: Mechanical Engineering
- All Subjects: Jazz
- Creators: Jiang, Hanqing
Description
With the increasing focus on developing environmentally benign electronic packages, lead-free solder alloys have received a great deal of attention. Mishandling of packages, during manufacture, assembly, or by the user may cause failure of solder joint. A fundamental understanding of the behavior of lead-free solders under mechanical shock conditions is lacking. Reliable experimental and numerical analysis of lead-free solder joints in the intermediate strain rate regime need to be investigated. This dissertation mainly focuses on exploring the mechanical shock behavior of lead-free tin-rich solder alloys via multiscale modeling and numerical simulations. First, the macroscopic stress/strain behaviors of three bulk lead-free tin-rich solders were tested over a range of strain rates from 0.001/s to 30/s. Finite element analysis was conducted to determine appropriate specimen geometry that could reach a homogeneous stress/strain field and a relatively high strain rate. A novel self-consistent true stress correction method is developed to compensate the inaccuracy caused by the triaxial stress state at the post-necking stage. Then the material property of micron-scale intermetallic was examined by micro-compression test. The accuracy of this measure is systematically validated by finite element analysis, and empirical adjustments are provided. Moreover, the interfacial property of the solder/intermetallic interface is investigated, and a continuum traction-separation law of this interface is developed from an atomistic-based cohesive element method. The macroscopic stress/strain relation and microstructural properties are combined together to form a multiscale material behavior via a stochastic approach for both solder and intermetallic. As a result, solder is modeled by porous plasticity with random voids, and intermetallic is characterized as brittle material with random vulnerable region. Thereafter, the porous plasticity fracture of the solders and the brittle fracture of the intermetallics are coupled together in one finite element model. Finally, this study yields a multiscale model to understand and predict the mechanical shock behavior of lead-free tin-rich solder joints. Different fracture patterns are observed for various strain rates and/or intermetallic thicknesses. The predictions have a good agreement with the theory and experiments.
ContributorsFei, Huiyang (Author) / Jiang, Hanqing (Thesis advisor) / Chawla, Nikhilesh (Thesis advisor) / Tasooji, Amaneh (Committee member) / Mobasher, Barzin (Committee member) / Rajan, Subramaniam D. (Committee member) / Arizona State University (Publisher)
Created2011
Description
Concrete columns constitute the fundamental supports of buildings, bridges, and various other infrastructures, and their failure could lead to the collapse of the entire structure. As such, great effort goes into improving the fire resistance of such columns. In a time sensitive fire situation, a delay in the failure of critical load bearing structures can lead to an increase in time allowed for the evacuation of occupants, recovery of property, and access to the fire. Much work has been done in improving the structural performance of concrete including reducing column sizes and providing a safer structure. As a result, high-strength (HS) concrete has been developed to fulfill the needs of such improvements. HS concrete varies from normal-strength (NS) concrete in that it has a higher stiffness, lower permeability and larger durability. This, unfortunately, has resulted in poor performance under fire. The lower permeability allows for water vapor to build up causing HS concrete to suffer from explosive spalling under rapid heating. In addition, the coefficient of thermal expansion (CTE) of HS concrete is lower than that of NS concrete. In this study, the effects of introducing a region of crumb rubber concrete into a steel-reinforced concrete column were analyzed. The inclusion of crumb rubber concrete into a column will greatly increase the thermal resistivity of the overall column, leading to a reduction in core temperature as well as the rate at which the column is heated. Different cases were analyzed while varying the positioning of the crumb-rubber region to characterize the effect of position on the improvement of fire resistance. Computer simulated finite element analysis was used to calculate the temperature and strain distribution with time across the column's cross-sectional area with specific interest in the steel - concrete region. Of the several cases which were investigated, it was found that the improvement of time before failure ranged between 32 to 45 minutes.
ContributorsZiadeh, Bassam Mohammed (Author) / Phelan, Patrick (Thesis advisor) / Kaloush, Kamil (Thesis advisor) / Jiang, Hanqing (Committee member) / Arizona State University (Publisher)
Created2011
Description
Pb-free solders are used as interconnects in various levels of micro-electronic packaging. Reliability of these interconnects is very critical for the performance of the package. One of the main factors affecting the reliability of solder joints is the presence of porosity which is introduced during processing of the joints. In this thesis, the effect of such porosity on the deformation behavior and eventual failure of the joints is studied using Finite Element (FE) modeling technique. A 3D model obtained by reconstruction of x-ray tomographic image data is used as input for FE analysis to simulate shear deformation and eventual failure of the joint using ductile damage model. The modeling was done in ABAQUS (v 6.10). The FE model predictions are validated with experimental results by comparing the deformation of the pores and the crack path as predicted by the model with the experimentally observed deformation and failure pattern. To understand the influence of size, shape, and distribution of pores on the mechanical behavior of the joint four different solder joints with varying degrees of porosity are modeled using the validated FE model. The validation technique mentioned above enables comparison of the simulated and actual deformation only. A more robust way of validating the FE model would be to compare the strain distribution in the joint as predicted by the model and as observed experimentally. In this study, to enable visualization of the experimental strain for the 3D microstructure obtained from tomography, a three dimensional digital image correlation (3D DIC) code has been implemented in MATLAB (MathWorks Inc). This developed 3D DIC code can be used as another tool to verify the numerical model predictions. The capability of the developed code in measuring local displacement and strain is demonstrated by considering a test case.
ContributorsJakkali, Vaidehi (Author) / Chawla, Nikhilesh K (Thesis advisor) / Jiang, Hanqing (Committee member) / Solanki, Kiran (Committee member) / Arizona State University (Publisher)
Created2011
Description
The study of artist transcriptions is an effective vehicle for assimilating the language and style of jazz. Pairing transcriptions with historical context provides further insight into the back story of the artists' life and method. Innovators are often the subject of published studies of this kind, but transcriptions of plunger-mute master Al Grey have been overlooked. This document fills that void, combining historical context with thirteen transcriptions of Grey's trombone features and improvisations. Selection of transcribed materials was based on an examination of historically significant solos in Al Grey's fifty-five-year career. The results are a series of open-horn and plunger solos that showcase Grey's sound, technical brilliance, and wide range of dynamics and articulation. This collection includes performances from a mix of widely available and obscure recordings, the majority coming from engagements with the Count Basie Orchestra. Methods learned from the study of Al Grey's book Plunger Techniques were vital in the realization of his work. The digital transcription software Amazing Slow Downer by Roni Music aided in deciphering some of Grey's more complicated passages and, with octave displacement, helped bring previously inaudible moments to the foreground.
ContributorsHopkins, Charles E (Author) / Pilafian, Sam (Thesis advisor) / Stauffer, Sandra (Committee member) / Solís, Ted (Committee member) / Ericson, John (Committee member) / Kocour, Michael (Committee member) / Arizona State University (Publisher)
Created2011
Description
This study examines the experiences of participants enrolled in an online community college jazz history course. I surveyed the participants before the course began and observed them in the online space through the duration of the course. Six students also participated in interviews during and after the course. Coded data from the interviews, surveys, and recorded discussion posts and journal entries provided evidence about the nature of interaction and engagement in learning in an online environment. I looked for evidence either supporting or detracting from a democratic online learning environment, concentrating on the categories of student engagement, freedom of expression, and accessibility. The data suggested that the participants' behaviors in and abilities to navigate the online class were influenced by their pre-existing native media habits. Participants' reasons for enrolling in the online course, which included convenience and schedule flexibility, informed their actions and behaviors in the class. Analysis revealed that perceived positive student engagement did not contribute to a democratic learning environment but rather to an easy, convenient experience in the online class. Finally, the data indicated that participants' behaviors in their future lives would not be affected by the online class in that their learning experiences were not potent enough to alter or inform their behavior in society. As online classes gain popularity, the ability of these classes to provide meaningful learning experiences must be questioned. Students in this online jazz history class presented, at times, a façade of participation and community building but demonstrated a lack of sincerity and interest in the course. The learning environment supported accessibility and freedom of expression to an extent, but students' engagement with their peers was limited. Overall, this study found a need for more research into the quality of online classes as learning platforms that support democracy, student-to-student interaction, and community building.
ContributorsHunter, Robert W. (Author) / Stauffer, Sandra L (Thesis advisor) / Tobias, Evan (Thesis advisor) / Bush, Jeffrey (Committee member) / Kocour, Michael (Committee member) / Pilafian, Sam (Committee member) / Arizona State University (Publisher)
Created2011
Description
This thesis focuses on the continued extension, validation, and application of combined thermal-structural reduced order models for nonlinear geometric problems. The first part of the thesis focuses on the determination of the temperature distribution and structural response induced by an oscillating flux on the top surface of a flat panel. This flux is introduced here as a simplified representation of the thermal effects of an oscillating shock on a panel of a supersonic/hypersonic vehicle. Accordingly, a random acoustic excitation is also considered to act on the panel and the level of the thermo-acoustic excitation is assumed to be large enough to induce a nonlinear geometric response of the panel. Both temperature distribution and structural response are determined using recently proposed reduced order models and a complete one way, thermal-structural, coupling is enforced. A steady-state analysis of the thermal problem is first carried out that is then utilized in the structural reduced order model governing equations with and without the acoustic excitation. A detailed validation of the reduced order models is carried out by comparison with a few full finite element (Nastran) computations. The computational expedience of the reduced order models allows a detailed parametric study of the response as a function of the frequency of the oscillating flux. The nature of the corresponding structural ROM equations is seen to be of a Mathieu-type with Duffing nonlinearity (originating from the nonlinear geometric effects) with external harmonic excitation (associated with the thermal moments terms on the panel). A dominant resonance is observed and explained. The second part of the thesis is focused on extending the formulation of the combined thermal-structural reduced order modeling method to include temperature dependent structural properties, more specifically of the elasticity tensor and the coefficient of thermal expansion. These properties were assumed to vary linearly with local temperature and it was found that the linear stiffness coefficients and the "thermal moment" terms then are cubic functions of the temperature generalized coordinates while the quadratic and cubic stiffness coefficients were only linear functions of these coordinates. A first validation of this reduced order modeling strategy was successfully carried out.
ContributorsMatney, Andrew (Author) / Mignolet, Marc (Thesis advisor) / Jiang, Hanqing (Committee member) / Spottswood, Stephen (Committee member) / Arizona State University (Publisher)
Created2011
Description
Damage assessment and residual useful life estimation (RULE) are essential for aerospace, civil and naval structures. Structural Health Monitoring (SHM) attempts to automate the process of damage detection and identification. Multiscale modeling is a key element in SHM. It not only provides important information on the physics of failure, such as damage initiation and growth, the output can be used as "virtual sensing" data for detection and prognosis. The current research is part of an ongoing multidisciplinary effort to develop an integrated SHM framework for metallic aerospace components. In this thesis a multiscale model has been developed by bridging the relevant length scales, micro, meso and macro (or structural scale). Micro structural representations obtained from material characterization studies are used to define the length scales and to capture the size and orientation of the grains at the micro level. Parametric studies are conducted to estimate material parameters used in this constitutive model. Numerical and experimental simulations are performed to investigate the effects of Representative Volume Element (RVE) size, defect area fraction and distribution. A multiscale damage criterion accounting for crystal orientation effect is developed. This criterion is applied for fatigue crack initial stage prediction. A damage evolution rule based on strain energy density is modified to incorporate crystal plasticity at the microscale (local). Optimization approaches are used to calculate global damage index which is used for the RVE failure prediciton. Potential cracking directions are provided from the damage criterion simultaneously. A wave propagation model is incorporated with the damage model to detect changes in sensing signals due to plastic deformation and damage growth.
ContributorsLuo, Chuntao (Author) / Chattopadhyay, Aditi (Thesis advisor) / Papandreou-Suppappola, Antonia (Committee member) / Jiang, Hanqing (Committee member) / Dai, Lenore (Committee member) / Li, Jian (Committee member) / Arizona State University (Publisher)
Created2011
Description
The Vocal Jazz ensemble, a uniquely American choral form, has grown and flourished in the past half century largely through the efforts of professionals and educators throughout the collegiate music community. This document provides historical data as presented through live and published interviews with key individuals involved in the early development of collegiate Vocal Jazz, as well as those who continue this effort currently. It also offers a study of the most influential creative forces that provided the spark for everyone else's fire. A frank discussion on the obstacles encountered and overcome is central to the overall theme of this research into a genre that has moved from a marginalized afterthought to a legitimate, more widely accepted art form. In addition to the perspective provided to future generations of educators in this field, this document also discusses the role of collegiate music academia in preserving and promoting the Vocal Jazz ensemble. The discussion relies on recent data showing the benefits of Vocal Jazz training and the need for authenticity towards its universal integration into college and university vocal performance and music education training.
ContributorsAmerind, Gregory (Author) / Kocour, Michael (Thesis advisor) / Carpenter, Ellon (Committee member) / Britton, David (Committee member) / Ryan, Russell (Committee member) / Arizona State University (Publisher)
Created2013
Description
Jazz continues, into its second century, as one of the most important musics taught in public middle and high schools. Even so, research related to how students learn, especially in their earliest interactions with jazz culture, is limited. Weaving together interviews and observations of junior and senior high school jazz players and teachers, private studio instructors, current university students majoring in jazz, and university and college jazz faculty, I developed a composite sketch of a secondary school student learning to play jazz. Using arts-based educational research methods, including the use of narrative inquiry and literary non-fiction, the status of current jazz education and the experiences by novice jazz learners is explored. What emerges is a complex story of students and teachers negotiating the landscape of jazz in and out of early twenty-first century public schools. Suggestions for enhancing jazz experiences for all stakeholders follow, focusing on access and the preparation of future jazz teachers.
ContributorsKelly, Keith B (Author) / Stauffer, Sandra (Thesis advisor) / Tobias, Evan (Committee member) / Kocour, Michael (Committee member) / Sullivan, Jill (Committee member) / Schmidt, Margaret (Committee member) / Arizona State University (Publisher)
Created2013
Description
This project sheds light on trombonist Andy Martin's improvisation and provides tools for further learning. A biographical sketch gives background on Martin, establishing him as a newer jazz master. Through the transcription and analysis of nine improvised solos, Martin's improvisational voice and vocabulary is deciphered and presented as a series of seven thematic hooks. These patterns, rhythms, and gestures are described, analyzed, and presented as examples of how each is used in the solos. The hooks are also set as application exercises for learning jazz style and improvisation. These exercises demonstrate how to use Martin's hooks as a means for furthering one's own improvisation. A full method for successful transcription is also presented, along with the printed transcriptions and their accompanying information sheets.
ContributorsWilkinson, Michael Scott (Author) / Ericson, John (Thesis advisor) / Kocour, Michael (Committee member) / Solis, Theodore (Committee member) / Arizona State University (Publisher)
Created2013