1,721,022 research outputs found
An in-plane phase-field ductile fracture model for orthotropic paperboard material
Get PDFA phase-field ductile fracture formulation for orthotropic paperboard materials is proposed, based on an anisotropic, multi-surface elastoplastic model describing the in-plane behavior of paperboard. A variational statement for the finite-step elastoplastic problem is extended to include the variational description of Griffith-type brittle fracture by a phase-field gradient term. The interaction between plastic and fracture dissipation mechanisms is modeled by introducing a scalar modulation function, assuming plasticity driven damage growth. This function depends on a scalar measure of the plastic strain components in the material orthotropy frame. It modifies the fracture activation criterion in a non-variational fashion, resulting in a direction-dependent material strength against crack propagation. The model performance is assessed by comparing numerical simulations and experimental tests conducted in a climate-controlled laboratory
Efficient and accurate simulation of the packaging forming process
No full textTo allow for large-scale forming applications, such as converting paperboard into package containers, efficient and reliable numerical tools are needed. In finite element simulations of thin structures, elements including structural features are required to reduce the computational cost. Solid-shell elements based on reduced integration with hourglass stabilization is an attractive choice. One advantage of this choice is the natural inclusion of the thickness, not present in standard degenerated shells, which is especially important for many problems involving contact. Furthermore, no restrictions are imposed on the constitutive models since the solid-shell element does not require the plane stress condition to be enforced. In this work, a recently proposed efficient solid-shell element is implemented together with a state-of-the-art continuum model for paperboard. This approach is validated by comparing the obtained numerical results with experimental results for paperboard as well as with those found by using 3D continuum elements. To show the potential of this approach, a large-scale forming simulation of paperboard is used as a proof of concept
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
Crack-growth-rate Estimation on a Three-point Bend Specimen During Low-cycle Fatigue
No full textThe ratio of the change of the clip-gage measured crack-opening displacement of a three-point bend specimen to the change of the displacement at the point of application of the cyclic load is shown to vary linearly with the ratio of the crack length to the specimen height. With the aid of this relation, the crack-growth rate is obtained by numerical differentiation of the crack length with respect to the number of load cycles. A clip-gage correction factor is introduced in order to compensate for the use of external edges to position the clip-gage during the experiment
A modification of the Tsai-Wu failure criterion for the biaxial strength of paper
No full textPrediction of the in-plane biaxial strength of paper by the Tsai-Wu failure criterion has in general proved to be in good agreement with experimental data. However, the Tsai-Wu criterion overestimates the strength in some parts of the biaxial tension region. This shortcoming can be corrected by adding a pair of cubic terms to the existing Tsai-Wu criterion. The modified Tsai-Wu criterion presented here predicts the biaxial strength of paper more accurately than the Tsai-Wu criterion. The extra pair of parameters introduced is determined ftom data obtained by standard tests
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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