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Internal Length Scales in Damaged Solids: and elastoplastic fluid saturated porous media. Griffith and Gioda G. (Eds), CISM course on Advanced numerical applications and plasticity in geomechanics, 1-23, Springer Verlag Wien New York.
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On intersonic crack propagation in poroelastic fluid-saturated solids
No full textA closed-form solution is provided for the stress, pore pressure and displacement fields near the tip of a dynamic crack steadily propagating in an elastic fluid-saturated porous solid at crack tip speed ranging between the faster longitudinal wave-speed and the lower between the longitudinal Biot second wave-speed and the shear wave-speed. The Biot theory of poroelasticity with inertia forces is assumed to govern the motion of the medium. At variance with the subsonic case, for intersonic crack propagation the stress and pore pressure fields display a strong discontinuity (shock wave) across symmetric rays emanating from the moving crack tip. However, for favorable velocity regimes the stress and pore pressure singularity turns out to be weaker than square-root, leading to a vanishing small energy release rate at the crack tip. The introduction of a finite length cohesive zone remedies the vanishing of fracture energy, which is due to the point size model of the process zone
A unified multifield formulation in nonlocal damage
No full textThe focus is on isotropic damaging materials where damage is driven by the nonlocal equivalent strain. The nonlocal
equivalent strain definition is inserted into the work function by a Lagrangian multiplier. This Lagrangian formulation depends
on: displacement, nonlocal equivalent strain and Lagrangian multiplier, and provides a variational basis supporting multifield
formulations of both integral and implicit gradient type. Finite element results are presented for some representative one- and
two-dimensional examples
Strain localization for a class of anisotropic elastic-plastic solids
No full textLocalization of deformation is analyzed in elastic-anisotropic plastic solids with non-associative flow law. A particular form of elastic anisotropy is considered, for which the localization analysis can be performed with reference to isotropic-elastic plastic solids having non-coaxial yield function and plastic potential. In this framework, a new analytical solution is presented restricted to plane strain or plane stress assumption
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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