Matching Items (178)
Description
There is a high demand for customized designs of various types of cement-based materials in order to address specific purposes in the construction field. These demands stem from the need to optimize the cementitious matrix properties and reinforcement choices, especially in high reliability, durability, and performance applications that include infrastructure, energy production, commercial buildings, and may ultimately be extended to low risk/high volume applications such as residential applications. The typical tools required to guide practicing engineers should be based on optimization algorithms that require highly efficient capacity and design alternatives and optimal computational tools. The general case of flexural design of members is an important aspect of design of structural members which can be extended to a variety of applications that include various cross-sections such as rectangular, W-sections, channels, angles, and T sections. The model utilized the simplified linear constitutive response of cement-based composite in compression and tension and extends into a two-segment elastic-plastic, strain softening, hardening, tension-stiffening, and a multi-segment system. The generalized parametric model proposed uses a dimensionless system in the stress-strain materials diagram to formulate piecewise equations for an equilibrium of internal stresses and obtains strain distributions for the closed-form solution of neutral axis location. This would allow for the computation of piecewise moment-curvature response. The number of linear residual stress implemented is flexible to a user to maintain a robust response. In the present approach bilinear, trilinear, and quad-linear models are addressed and a procedure for incorporating additional segments is presented. Moreover, a closed-form solution of moment-curvature can be solved and employed in calculating load-deflection response. The model is adaptable for various types of fiber-reinforced and textile reinforced concrete (FRC, TRC, UHPC, AAC, and Reinforced Concrete). The extensions to cover continuous fiber reinforcement such as textile reinforced concrete (TRC, FRCM) strengthening and repair are addressed. The theoretical model is extended to incorporate the hybrid design (HRC) with continuous rebar with FRC to increase the ductility and ultimate moment capacity. HRC extends the performance of the fiber system to incorporate residual capacity into a serviceability-based design that reduced the reliance on the design based on the limit state. The design chart for HRC and as well as conventional RC has been generated for practicing engineering applications. Results are compared to a large array of data from experimental results conducted at the ASU structural lab facilities and other published literature.
Contributorspleesudjai, chidchanok (Author) / Mobasher, Barzin (Thesis advisor) / Neithalath, Narayanan (Committee member) / Rajan, Subramaniam (Committee member) / Arizona State University (Publisher)
Created2021
Description
The tensile stress–strain response of a fiber reinforced concrete dominates the performance under many loading conditions and applications. To represent this property as an average equivalent response, a back-calculation process from flexural testing is employed. The procedure is performed by model fitting of the three-point and four-point bending load deflection data on two types of macro synthetic polymeric fibers, one type of steel fiber and one type of Alkali Resistant (AR) glass fiber. A strain softening tensile model is used to simulate the behavior of different FRC types and obtain the experimental flexural response. The stress–strain model for each age, fiber type and dosage rate is simulated by means of the inverse analysis procedure, using closed-form moment–curvature relationship and load–deflection response of the piecewise-linear material. The method of approach is further applied to one external data set for High Performance Fiber Reinforced Concrete (HPFRC) with two different types of steel fibers and validated by tensile test results reported. Results of back-calculation of stress–strain responses by tri-linear tensile model for all mixtures are compared and correlated with the corresponding standard method parameters used for post crack behavior characterization and a regression analysis for comparative evaluation of test data is presented.
ContributorsMobasher, Barzin (Author) / Bakhshi, Mehdi (Author) / Barsby, Christopher (Author) / Ira A. Fulton Schools of Engineering (Contributor)
Created2014-11-15
Description
This study examined an adverse effect of an adolescent group intervention. Group interventions represent one of the most economical, convenient, and common solution to adolescent behavior problems, although prior findings from program evaluation studies have suggested that these groups can unexpectedly increase the externalizing behaviors that they were designed to reduce or prevent. The current study used data from a longitudinal, randomized controlled trial of the Bridges to High School / Puentes a La Secundaria Program, a multicomponent prevention program designed to reduce risk during the middle school transition, which has demonstrated positive effects across an array of outcomes. Data were collected at the beginning of 7th grade, with follow-up data collected at the end of the 7th, 8th, 9th, and 12th grade from a sample of Mexican American adolescents and their mothers. Analyses evaluated long-term effects on externalizing outcomes, trajectories of externalizing behaviors across adolescence, and potential mediators of observed effects. Results showed that the adverse effect that was originally observed based on adolescent self-report of externalizing symptoms at 1-year posttest among youth with high pretest externalizing symptoms was not maintained over time and was not reflected in changes in adolescents' trajectories of externalizing behaviors. Moreover, neither of the peer mediators that theory suggests would explain adverse effects were found to mediate the relationship between intervention status and externalizing symptoms at 1-year posttest. Finally, only beneficial effects were found on externalizing symptoms based on mother report. Together, these findings suggest that the Bridges intervention did not adversely affect adolescent problem behaviors and that future studies should use caution when interpreting unexpected adverse effects.
ContributorsWong, Jessie Jong-Chee (Author) / Gonzales, Nancy A. (Thesis advisor) / West, Stephen G. (Thesis advisor) / Chassin, Laurie (Committee member) / Dishion, Thomas (Committee member) / Arizona State University (Publisher)
Created2015
Description
Composite materials are finally providing uses hitherto reserved for metals in structural systems applications – airframes and engine containment systems, wraps for repair and rehabilitation, and ballistic/blast mitigation systems. They have high strength-to-weight ratios, are durable and resistant to environmental effects, have high impact strength, and can be manufactured in a variety of shapes. Generalized constitutive models are being developed to accurately model composite systems so they can be used in implicit and explicit finite element analysis. These models require extensive characterization of the composite material as input. The particular constitutive model of interest for this research is a three-dimensional orthotropic elasto-plastic composite material model that requires a total of 12 experimental stress-strain curves, yield stresses, and Young’s Modulus and Poisson’s ratio in the material directions as input. Sometimes it is not possible to carry out reliable experimental tests needed to characterize the composite material. One solution is using virtual testing to fill the gaps in available experimental data. A Virtual Testing Software System (VTSS) has been developed to address the need for a less restrictive method to characterize a three-dimensional orthotropic composite material. The system takes in the material properties of the constituents and completes all 12 of the necessary characterization tests using finite element (FE) models. Verification and validation test cases demonstrate the capabilities of the VTSS.
ContributorsHarrington, Joseph (Author) / Rajan, Subramaniam D. (Thesis advisor) / Neithalath, Narayanan (Committee member) / Mobasher, Barzin (Committee member) / Arizona State University (Publisher)
Created2015
Description
A simplified bilinear moment-curvature model are derived based on the moment-curvature response generated from a parameterized stress-strain response of strain softening and or strain-hardening material by Dr. Barzin Mobasher and Dr. Chote Soranakom. Closed form solutions are developed for deflection calculations of determinate beams subjected to usual loading patterns at any load stage. The solutions are based on a bilinear moment curvature response characterized by the flexural crack initiation and ultimate capacity based on a deflection hardening behavior. Closed form equations for deflection calculation are presented for simply supported beams under three point bending, four point bending, uniform load, concentrated moment at the middle, pure bending, and for cantilever beam under a point load at the end, a point load with an arbitrary distance from the fixed end, and uniform load. These expressions are derived for pre-cracked and post cracked regions. A parametric study is conducted to examine the effects of moment and curvature at the ultimate stage to moment and curvature at the first crack ratios on the deflection. The effectiveness of the simplified closed form solution is demonstrated by comparing the analytical load deflection response and the experimental results for three point and four point bending. The simplified bilinear moment-curvature model is modified by imposing the deflection softening behavior so that it can be widely implemented in the analysis of 2-D panels. The derivations of elastic solutions and yield line approach of 2-D panels are presented. Effectiveness of the proposed moment-curvature model with various types of panels is verified by comparing the simulated data with the experimental data of panel test.
ContributorsWang, Xinmeng (Author) / Mobasher, Barzin (Thesis advisor) / Rajan, Subramaniam D. (Committee member) / Neithalath, Narayanan (Committee member) / Arizona State University (Publisher)
Created2015
Description
The concert vocalise, a dazzling wordless vocal etude intended for performance, is largely a phenomenon of the twentieth century. Made famous by composers such as Sergei Rachmaninoff and Maurice Ravel, the concert vocalise is generally a short, non-programmatic work with a relatively simple form. In contrast, Nikolai Medtner’s two monumental Op. 41 vocalises, the Sonata-Vocalise mit einem Motto “Geweihter Platz and the Suite Vocalise, are staggering in their length and formal complexity. They are also programmatically conceived, sharing the Goethe poem “Geweihter Platz” as their inspiration.
The innovation of adding a textual element to a traditionally textless genre introduces a tantalizing new layer of complexity that demands further research and exploration. However, as with any innovation, it also offers new challenges to performers wishing to program either or both works. Current scholarship has yet to offer any kind of in-depth analysis of either work, leaving questions as to the structural and motivic elements which bind these large works together, not to mention questions related to exactly how Medtner addresses the challenge of linking specific parts of Goethe’s text to the textless portions of music. Furthermore, neither work is considered standard repertoire, and recordings and performances are limited, leaving aspiring performers in something of an informational desert.
In this paper, I endeavor to fill this informational gap for performers and scholars alike by providing them with a brief biography of Medtner, an outline of the development of the concert vocalise genre, and the background of the Goethe poem that inspired Medtner. Then my in-depth analyses reveal underlying structural, motivic, and programmatic links both within and between the works. Finally, my performer’s guide, based on the analyses and my experience performing both works, offers suggestions regarding the interpretational, ensemble, and technical challenges presented by these great works.
The innovation of adding a textual element to a traditionally textless genre introduces a tantalizing new layer of complexity that demands further research and exploration. However, as with any innovation, it also offers new challenges to performers wishing to program either or both works. Current scholarship has yet to offer any kind of in-depth analysis of either work, leaving questions as to the structural and motivic elements which bind these large works together, not to mention questions related to exactly how Medtner addresses the challenge of linking specific parts of Goethe’s text to the textless portions of music. Furthermore, neither work is considered standard repertoire, and recordings and performances are limited, leaving aspiring performers in something of an informational desert.
In this paper, I endeavor to fill this informational gap for performers and scholars alike by providing them with a brief biography of Medtner, an outline of the development of the concert vocalise genre, and the background of the Goethe poem that inspired Medtner. Then my in-depth analyses reveal underlying structural, motivic, and programmatic links both within and between the works. Finally, my performer’s guide, based on the analyses and my experience performing both works, offers suggestions regarding the interpretational, ensemble, and technical challenges presented by these great works.
ContributorsUhl, Nathan Leonard (Author) / Campbell, Andrew (Thesis advisor) / Carpenter, Ellon (Thesis advisor) / FitzPatrick, Carole (Committee member) / Ryan, Russell (Committee member) / Arizona State University (Publisher)
Created2017
Description
The Sonata for Cello and Piano (1915) was one of the last three sonatas written by Claude Debussy (1862–1918). When Debussy composed the sonata, France was involved in World War I and Debussy was influenced by political dogmas that sought to advance nationalism as well as the use of French traditions in musical compositions. By discussing the political impact of World War I on French music, this paper will place the Sonata in a context that strengthens the understanding of the work.
Debussy, who participated in the political project of seeking out tradition as the protector of French culture, also presents his understanding of what French tradition is in this sonata. An analytical description of the structure, thematic materials, harmonies and intervallic relationships of the Sonata reveals Debussy’s approach of combining the elements that he observed from his French predecessors, as well as his own innovations in the work as he negotiated musical world that was controlled by political dogma
Debussy, who participated in the political project of seeking out tradition as the protector of French culture, also presents his understanding of what French tradition is in this sonata. An analytical description of the structure, thematic materials, harmonies and intervallic relationships of the Sonata reveals Debussy’s approach of combining the elements that he observed from his French predecessors, as well as his own innovations in the work as he negotiated musical world that was controlled by political dogma
ContributorsSong, Peipei (Author) / Ryan, Russell (Thesis advisor) / Campbell, Andrew (Committee member) / Feisst, Sabine (Committee member) / Landschoot, Thomas (Committee member) / Arizona State University (Publisher)
Created2016
Description
Unidirectional glass fiber reinforced polymer (GFRP) is tested at four initial strain rates (25, 50, 100 and 200 s-1) and six temperatures (−25, 0, 25, 50, 75 and 100 °C) on a servo-hydraulic high-rate testing system to investigate any possible effects on their mechanical properties and failure patterns. Meanwhile, for the sake of illuminating strain rate and temperature effect mechanisms, glass yarn samples were complementally tested at four different strain rates (40, 80, 120 and 160 s-1) and varying temperatures (25, 50, 75 and 100 °C) utilizing an Instron drop-weight impact system. In addition, quasi-static properties of GFRP and glass yarn are supplemented as references. The stress–strain responses at varying strain rates and elevated temperatures are discussed. A Weibull statistics model is used to quantify the degree of variability in tensile strength and to obtain Weibull parameters for engineering applications.
ContributorsOu, Yunfu (Author) / Zhu, Deju (Author) / Zhang, Huaian (Author) / Huang, Liang (Author) / Yao, Yiming (Author) / Li, Gaosheng (Author) / Mobasher, Barzin (Author) / Ira A. Fulton Schools of Engineering (Contributor)
Created2016-05-19