1,720,971 research outputs found
INVESTIGATION INTO TOOL SURFACE DESCRIPTION FOR FINITE-ELEMENT ANALYSIS OF 3-DIMENSIONAL SHEET-METAL FORMING PROCESSES
No full textA general method for the mathematical description of arbitrarily-shaped tool surfaces is proposed by introducing the parametric and non-parametric patch approaches. The cubic Ferguson patch is employed to describe the tool surface in the parametric patch approach and an efficient contact search algorithm is suggested to make this parametric patch approach more realistic for the FE analysis. The non-parametric patch approach introduces a cubic blending function as in the case of the parametric patch approach to allow C1 continuity. In the approach, an array of equi-spaced points is required to construct the whole tool surface. Computations are carried out for some complex sheet forming examples including actual auto-body panel to verify the validity and the robustness of the developed contact search algorithms
RIGID-PLASTIC FINITE-ELEMENT ANALYSIS OF SHEET-METAL FORMING PROCESSES USING CONTINUOUS CONTACT TREATMENT AND MEMBRANE ELEMENTS INCORPORATING BENDING EFFECTS
No full textAn improved method of contact treatment is developed in which both the FEM (finite element method) mesh and the tool surfaces are described with parametric patches which have C1 continuity or more. The FEM mesh at the current configuration is globally converted into smooth surface patches of net form. A continuous sheet surface normal scheme is devised by using the globally smoothed mesh surface. A robust and efficient contact search algorithm is also developed in connection with the proposed continuous contact treatment. As an improved version of conventional membrane element, the BEAM (abbreviated from Bending Energy Augmented Membrane) element is newly developed based on node spring. In order to verify the effectiveness of the proposed continuous contact treatment and BEAM element, deep drawing processes of complicated parts including actual auto-body panel are analysed. Comparisons with the available experiment and analysis show that the proposed continuous contact treatment in connection with BEAM elements can be effectively applied to the analysis of sheet metal forming processes for arbitrarily curved parts with deformation regions in which the bending effect must be taken into account
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
FINITE-ELEMENT ANALYSIS AND DESIGN OF BINDER WRAPS FOR AUTOMOBILE SHEET-METAL PARTS USING SURFACE BOUNDARY-CONDITION
No full textThe forming of automobile sheet metal parts in a draw die consists of clamping a blank by binders to form a binder wrap and drawing the blank into the final part. This paper proposes a numerical method to calculate the binder wrap. A blank is composed of two regions: the contact region with the die face and the noncontact region of the die cavity, In this study, surface boundary condition is suggested for calculating the configuration of the binder wrap. Surface boundary condition means that the three-dimensional geometric data of the die face are used as the base for the displacement boundary condition of the finite-element analysis. To verify the validity of the proposed method, the binder wraps of complicated automobile parts, including a front fender and a trunk lid, are analyzed
COMPARATIVE INVESTIGATION INTO IMPLICIT, EXPLICIT, AND ITERATIVE IMPLICIT EXPLICIT SCHEMES FOR THE SIMULATION OF SHEET-METAL FORMING PROCESSES
No full textThe objective of the paper is to make comparison of the effectiveness of implicit, explicit and iterative implicit/explicit finite-element analysis methods for the analysis of static and dynamic sheet-forming problems. In the finite-element simulation of sheet-metal forming processes, the robustness and stability of computation are important requirements, since the computation time and convergency became major points of consideration due to the complexity of the geometry and the boundary conditions. The implicit scheme employs a more reliable and rigorous scheme in considering the equilibrium at each step of deformation, while in the explicit scheme the problem of convergency is eliminated at the cost of solution accuracy. In the present work the rigid-plastic finite-element method using both the usual membrane elements and bending-energy-augmented membrane elements (BEAM) is employed for computation. Computations are carried out for some typical sheet-forming examples by implicit, explicit, iterative implicit/explicit schemes, including deep-drawing involving two-dimensional hemispherical stretching, a square box and an oil pan. From comparison of the methods, their advantages and disadvantages are discussed
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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