1,720,993 research outputs found
A comparison of numerical methods to predict the progressive collapse of lightweight aluminium vessels
No full textThis article presents a comparison of several methods to predict the primary longitudinal bending moment-curvature relationship for a series of box beams with dimensions equivalent to a large, lightweight aluminium ship. The comparative study includes the application of an extended progressive collapse methodology, which has been developed specifically to predict the strength behavior of lightweight hull structures under primary bending moment and accounts for compartment-level, gross panel buckling effects of the orthogonally stiffened structure. The approach is based on the principles of the Smith progressive collapse method, which has been shown to be a capable measure of ultimate strength when applied to steel ships. However, a fundamental premise of the Smith method is that buckling forms an interframe. The extended method discards this assumption and includes overall gross panel buckling effects in the determination of girder strength. For the case study, both the interframe and compartment behavior of the case study box girders are compared. The results are also compared with nonlinear finite element analyses of the box girders. The nonlinear finite element method is being increasingly applied to predict hull girder progressive collapse and, provided computation time is acceptable, will predict collapse modes over an entire compartment. The extended progressive collapse method is shown to compare favorably to the equivalent finite element analysis when overall buckling modes dominate.</p
A comparison of numerical methods to predict the progressive collapse of lightweight aluminium vessels
No full textThis article presents a comparison of several methods to predict the primary longitudinal bending moment?curvature relationship for a series of box beams with dimensions equivalent to a large, lightweight aluminium ship. The comparative study includes the application of an extended progressive collapse methodology, which has been developed specifically to predict the strength behavior of lightweight hull structures under primary bending moment and accounts for compartment-level, gross panel buckling effects of the orthogonally stiffened structure. The approach is based on the principles of the Smith progressive collapse method, which has been shown to be a capable measure of ultimate strength when applied to steel ships. However, a fundamental premise of the Smith method is that buckling forms an interframe. The extended method discards this assumption and includes overall gross panel buckling effects in the determination of girder strength. For the case study, both the interframe and compartment behavior of the case study box girders are compared. The results are also compared with nonlinear finite element analyses of the box girders. The nonlinear finite element method is being increasingly applied to predict hull girder progressive collapse and, provided computation time is acceptable, will predict collapse modes over an entire compartment. The extended progressive collapse method is shown to compare favorably to the equivalent finite element analysis when overall buckling modes dominat
Load shortening characteristics of marine grade aluminium alloy plates in longitudinal compression
No full textThis study presents detailed and rigorous numerical analysis for a parametric series of unstiffened aluminium plates typical of those used in lightweight ships and equivalent thin walled stiffened structures. The study is undertaken with a nonlinear finite element analysis procedure using ABAQUS. The strength behaviour of the plates under a progressively increasing longitudinal in-plane load are shown to be affected by a number of parameters including the alloy, geometric imperfection shape, heat affected zone distribution, level of heat softening and residual stress distribution. The comparative influences of these various factors, some of which are specific to welded aluminium structure, are explored to determine which must be accounted for in the development of a parametric series of design curve
An adapted orthotropic plate method to predict overall buckling of lightweight stiffened panels
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Full text linkWe 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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