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An anisotropic displacement correlation method for extraction of stress intensity factors from three-dimensional fractures
Get PDFA displacement correlation method (DCM) for the extraction of stress intensity factors (SIFs) from three-dimensional fractures in anisotropic bodies is presented in this work. The proposed anisotropic DCM is able to handle materials with rectilinear anisotropy in bodies with arbitrary crack geometry and material alignment. A high-order generalized finite element method (GFEM) approximation is used enriched with -hierarchical polynomials, discontinuous Heaviside functions, and singular crack front functions for the approximate displacement fields. The anisotropic DCM is able to match results against analytical solutions for single mode and mixed-mode fracture with high accuracy. Several problems with more complex geometry are investigated and compared against results in the literature. Excellent agreement is seen in all problems examined. The goal of this work is to present an efficient and accurate method for the extraction of SIFs in three-dimensional, mixed-mode fractures that is applicable for problems with any form of rectilinear anisotropy, arbitrary crack geometry, and any material alignment.Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2021-05-01The student, Bryce Mazurowski, accepted the attached license on 2019-04-19 at 20:23.The student, Bryce Mazurowski, submitted this Thesis for approval on 2019-04-19 at 20:30.This Thesis was approved for publication on 2019-04-22 at 10:46.DSpace SAF Submission Ingestion Package generated from Vireo submission #13804 on 2019-08-22 at 16:23:27Made available in DSpace on 2019-08-23T20:48:21Z (GMT). No. of bitstreams: 2
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Previous issue date: 2019-04-22Embargo set by: Seth Robbins for item 112360
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An anisotropic displacement correlation method for extraction of stress intensity factors from three-dimensional fractures
No full textA displacement correlation method (DCM) for the extraction of stress intensity factors (SIFs) from three-dimensional fractures in anisotropic bodies is presented in this work. The proposed anisotropic DCM is able to handle materials with rectilinear anisotropy in bodies with arbitrary crack geometry and material alignment. A high-order generalized finite element method (GFEM) approximation is used enriched with -hierarchical polynomials, discontinuous Heaviside functions, and singular crack front functions for the approximate displacement fields. The anisotropic DCM is able to match results against analytical solutions for single mode and mixed-mode fracture with high accuracy. Several problems with more complex geometry are investigated and compared against results in the literature. Excellent agreement is seen in all problems examined. The goal of this work is to present an efficient and accurate method for the extraction of SIFs in three-dimensional, mixed-mode fractures that is applicable for problems with any form of rectilinear anisotropy, arbitrary crack geometry, and any material alignment.LimitedAuthor requested closed access (OA after 2yrs) in Vireo ETD syste
A multiscale computational framework for ceramic composite structures with localized material nonlinearity
No full textSubmission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2025-03-28 without embargo termsThe student, Bryce Mazurowski, accepted the attached license on 2024-11-19 at 15:51.The student, Bryce Mazurowski, submitted this Dissertation for approval on 2024-11-19 at 21:12.This Dissertation was approved for publication on 2024-11-20 at 12:06.DSpace SAF Submission Ingestion Package generated from Vireo submission #21345 on 2025-03-28 at 14:25:43Composite materials are gaining ground as the material of choice in many structural applications. These tailored materials allow engineers to meet more aggressive design goals, but they bring significant analysis challenges. Nonlinear material behavior greatly complicates homogenization methods and multiscale analysis techniques. In applications like high-speed aircraft, material nonlinearity is an expectation. The loading and environment are too extreme for materials to maintain linear behavior. This nonlinearity is, however, often localized to stress concentrations around features like connections, sharp gradient loads, or areas of high temperature. This dissertation develops a computational framework that allows the majority of an analysis domain to use linear elastic homogenized material properties and coarse, dimensionally-reduced structural models. In localized areas around stress concentrations, material heterogeneity and nonlinearity are introduced through high-fidelity models capable of capturing failure. These local areas can appear anywhere in the analysis domain, as needed. Communication across scales allows global behavior to influence local behavior and vice-versa. A Generalized Finite Element Method with global-local enrichment functions (GFEMgl) is the backbone of this method. Coarse, defeatured global models use linear elastic, homogenized material models. Auxiliary local problems capture heterogeneous, nonlinear material behavior and introduce local structural features, like fasteners. State-of-the-art material models are used to capture damage in ceramic matrix composites (CMCs) around local structural features. These material models are introduced via local problems and carried into the global analysis. Modifications to the GFEMgl allow these local problems to be introduced anywhere in the analysis domain. The GFEMgl developed in this work bridges three material length scales: global homogenized behavior, explicit laminate modeling, and intraply CMC-specific damage with the aforementioned material models. The GFEMgl framework is also included in an Iterative Global-Local method to create an IGL- GFEMgl solution procedure. Shell elements are the de facto choice for modeling aircraft at the global scale, but they do not have the resolution to capture CMC failure. The IGL- GFEMgl allows global shell models to be coupled with the proposed GFEMgl framework to capture failure of the CMC material. This creates a complete analysis loop from a global aircraft model down to the material level, where all scales provide insight and feedback to one another. This work presents a systematic study of the proposed multiscale analysis method. Relevant CMC material models are developed, calibrated, and validated on their own. Then the proposed GFEMgl is presented and verified. CMC behavior around open holes and fasteners is explored with the GFEMgl, including the use of contact models across scales. The method is consistently compared against industry-adopted multiscale methods and experiments. The IGL- GFEMgl is then used to couple global shell models, solved in a commercial software, with the GFEMgl framework to capture local CMC behavior. The computational framework is simple, efficient, and very capable when compared to competing methods
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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