1,720,965 research outputs found
3D beam-column finite elements under tri-axial stess-strain states: non-uniform shear stress distribution and warping
Get PDFIn many engineering structures, the effects of shear and torsional loads are an important aspect of both the analysis and the design process. These effects are usually neglected in typical framed structures. However, in some relevant cases, such as bridges, shear walls or thin-walled frames, it is essential to account for the shear and torsional loads and their interaction with the other loading conditions to correctly reproduce the structural response.
In this framework, the main task is to accurately describe the nonlinear structural response in terms of global behavior and local stress-strain distributions, reproducing the coupling of the stress components and its influence on the global response. This results even more important in large scale structures made of cementitious and/or innovative composite materials, widely adopted in nowadays professional practice. Indeed, these structures usually show degrading mechanisms and softening behavior. Hence, they require sophisticated computational models and ad hoc analysis strategies to predict
the structure capacity under severe loading conditions.
A standard approach to analyze these structures is the adoption of beam-column finite element (FE) models, which are often preferred with respect to two-dimensional (2D) plate/shell or three-dimensional (3D) FEs, because of their efficiency and low computational cost. However, most beam-column FE formulations are based on theclassical Euler-Bernoulli or Timoshenko theory, assuming the cross-sections to remain plane during the loading process. This assumption requires specific corrective measures, when the shear and torsion and the related warping effects are pronounced.
This work discusses the simulation of RC members with a 3D 2-node beam FE that includes warping effects. The FE formulation in [1] is extended to allow the description of structural members with softening material behavior. The governing equations are derived from a four-field Hu-Washizu variational principle, with independent interpolation
of the warping displacement field from the rigid section displacements, the generalized section deformations and the material stress fields. In particular, the warping of the cross-section is described by interpolating the out-of-plane displacement with
the addition of a variable number of local degrees of freedom to those commonly used for the beam FE. The global nonlinear response and the local distributions of strains and stresses are described introducing a fiber cross-section discretization. Hence, the coupling of axial, flexural, shear and torsional effects in terms of material response is automatically taken into account.
Focusing on RC structures, the damaging mechanisms of the concrete material is described by adopting a new 3D nonlinear constitutive relationship with plasticity and damage. This is an enhanced version of that proposed in [2] and introduces the description of the unilateral effects typically appearing in concrete-like materials, due to the crack opening and closure. A Drucker-Prager type plastic model is coupled with a two-parameter isotropic damage model, where two scalar variables are used to describe the damage in tension and compression, respectively.
The localization problems and the related mesh-dependency, due to the softening material behavior, are controlled through a regularization technique based on a properly modified nonlocal integral procedure. For beam-column FEs, the nonlocal strain measures are evaluated performing the integration of the local generalized section deformations along the element axis, whereas for 2D FEs the nonlocal integration is performed considering the generalized membrane/plate deformations.
The proposed model is implemented and validated through some correlation studies. These consider the numerical analysis of a series of plain concrete and RC beams subjected to torsional loads and of two RC shear walls. The results are compared with experimental measurements and with those of standard FE beam models
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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