1,720,960 research outputs found
Impact characteristics of glass fiber composites with respect to fiber volume fraction
No full textThe impact energy absorption characteristics of glass epoxy composites and glass polyester composites with respect to fiber volume fraction were investigated by the instrumented Charpy impact test method. Also, the interlaminar shear properties were measured by the short beam shear test to investigate the correlation between the interlaminar shear properties and the impact energy absorption characteristics. Appropriate curing cycle was suggested for polyester resin by measuring the dissipation factor. Using the experimental results, the impact absorption characteristics of glass fiber composites such as fiber breakage and fiber pull-out and delamination were discussed
Impact Properties of Glass Fiber Composites with respect to Surface Treatment and Fiber Volume Fraction
No full textImpact energy absorption characteristics of glass fiber hybrid composites
No full textIn the present study, the impact energy absorption characteristics of glass fiber-reinforced hybrid composites were investigated by the instrumented Charpy impact test method with respect to the volume fraction of different materials embedded. Also, the interlaminar shear properties were measured by the short beam shear test to investigate the correlation between the interlaminar shear properties and the impact energy absorption characteristics. To predict the impact absorption characteristics of glass fiber hybrid composites, the progressive impact fracture model was proposed. (C) 1999 Elsevier Science Ltd. All rights reserved
Impact energy absorption characteristics of composite structures
No full textThe tensile and compressive tests of glass-epoxy composites with 1-200 s(-1) strain rates which are typical strain rate range during automobile crash accidents were performed in order to measure the strength variation with respect to strain rate. The tests were performed using both a horizontal type pneumatic impact tester and a conventional dynamic universal test machine with strain-rate-increase mechanisms. Also, the impact energy absorption characteristics of glass fiber reinforced composites were estimated using the newly proposed progressive impact fracture model. From the experiments and predictions, it was found that the proposed method predicted relatively well the experimental results. (C) 2000 Published by Elsevier Science Ltd. All rights reserved
Composite side-door impact beams for passenger cars
No full textThe fuel efficiency and emission gas regulation of passenger cars are two important issues nowadays. The best way to increase fuel efficiency without sacrificing safety is to employ fibre reinforced composite materials in the body of cars because fibre-reinforced composite materials have higher specific strengths than those of steel. In this study, the side-door impact beam for passenger cars was developed using glass-fibre-reinforced composite materials as metals usually have a lower capacity of impact absorption energy at Bow temperature compared with that of glass-fibre-reinforced composite materials. Static tests were carried out to determine the optimum fibre stacking sequences and cross-sectional thickness for the composite impact beams taking consideration of the weight saving ratio compared to the high strength steel. Dynamic tests were carried out at several different temperatures using the pneumatic impact tester, which was developed to investigate the dynamic characteristics of impact beams at a speed of 30 mph. Also, finite-element analyses were performed using ABAQUS, a commercial software to compare the simulated characteristics of the impact beams with the experimental results. From the comparison, it was found that the results from the finite-element analyses showed good agreement with the experimental results, although several assumptions were made in the finite-element analyses. (C) 1997 Elsevier Science Ltd
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
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