1,721,050 research outputs found
Shortening Effect on Buckling Behavior of Reddy Plates and Prismatic Plate Structures
No full textA closed-form solution based on the Reddy third-order shear deformation plate theory is proposed for the buckling
of both flat and stiffened plates, with simply supported on two opposite edges. The effect of the non-linear straindisplacement
terms, usually neglected under the von Kármán hypothesis, on the buckling of thick plates is
investigated, and the equations governing the critical behaviour considering the full Green-Lagrange strain tensor
and the second Piola-Kirchhoff stress tensor are derived using the principle of minimum potential energy. The
general Levy-type approach is employed, and the accuracy and effectiveness of the proposed formulation is
validated through direct comparison with analytical and numerical results available in the literature. The parametric
analyses performed for different geometrical ratios show that the von Kármán hypothesis holds only for thin flat
plates whereas it can significantly overestimate buckling loads for stiffened plates, for which the buckling mode
entails comparable in-plane and out-of-plane displacemen
A discrete differential geometry-based approach to buckling and vibration analyses of inhomogeneous Reddy plates
No full textIn this paper, a novel discrete differential geometry-based numerical procedure for buckling and vibration analyses of rectangular plates with non-uniform thickness is developed. In the proposed approach a plate is discretized using a finite number of rigid bars, lumped masses, and elastic rotational springs to simulate both bending and shear deformation responses, allowing the analysis of thick plates through the adoption of the Reddy’s third-order shear deformable plate theory. An interesting analogy between the proposed model and the central finite difference method for solving a set of partial differential equations is also highlighted, showing how the former can be seen as the physical model behind the mathematical representation of the latter. The numerical results presented show both the versatility and the accuracy of the proposed approach
Bending analysis of functionally graded rectangular plates using the dual mesh control domain method
No full textThe dual mesh control domain method (DMCDM) introduced by Reddy employs one mesh
for the approximation of the primary variables (primal mesh) and another mesh for the satisfaction
of the governing equations (dual mesh). The present study deals with the extension
and application of the DMCDM to functionally graded rectangular plates. The
formulation makes use of the traditional finite element interpolation of the primary variables
with a primal mesh and a dual mesh to satisfy the integral form of the governing differential
equations, the basic premise of the finite volume method. The method is used to
analyze bending of through-thickness functionally graded rectangular plates using the firstorder
shear deformation plate theory. Numerical results are presented to illustrate the methodology,
and a comparison of the displacements and stresses computed using the DMCDM
with those of the finite element model shows excellent agreement while requiring less formulative
(and possibly computational) effort. The influence of the extensional-bending coupling
stiffness (due to the through-thickness grading of the material) on the deflections is
also brought out
Analytical solution for a 5-parameter beam displacement model
No full textIn this paper, a new beam model based on a 5-parameter displacement field, accounting for an enhanced kinematics and able to reproduce the Poisson effect, is proposed. The displacement field enriches the classical three-parameter Timoshenko beam with two new parameters capable to simulate the shortening effect over the thickness. The related differential equations, derived from a variational formulation, are analytically solved and implemented in a deformation method approach, capable of solving structural problems of beams with general geometry, boundary and load conditions. Several numerical applications are developed, highlighting the characteristic of the proposed 5-parameters model and comparing the results with those obtained using the classical Bernoulli, Timoshenko and Reddy beam models. Numerical results show that, although for homogeneous beam the differences in terms of generalized stress and displacement are generally very small, the proposed model returns local stress enriched by the new parameters, with more significant differences where the Poisson effect is more pronounced
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
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