1,721,344 research outputs found
Fatigue limit: Is there a link to the quasi-static damage?
No full textThe paper presents experimentally and numerically observed relations of the fatigue life limit and the quasi-static damage threshold, which provide rough estimation for the design strains to use under fatigue strength requirements and allow planning of the fatigue testing programs to minimize the amount of costly and time-consuming experiments with low loads and high number of cycles
Acoustic emission and damage mode correlation in textile reinforced PPS composites
Full text linkThe paper applies the cluster analysis methodology to thermoplastic Polyphenylene sulphide (PPS) carbon woven composites. The experimental quasi-static tensile tests were assisted by: a digital camera for digital image correlation (DIC) evaluation of the full field strain; a digital camera for local damage observation; acoustic emission (AE) sensors for measurement of the acoustic emission features during loading. The experimental data and the subsequent cluster analyses of the AE events show a similar distribution of the AE clusters for the considered thermoplastic carbon composites and other thermoset woven composites described in the literature. The boundaries of those clusters are different for some extent, while a typical damage mechanism, namely transverse cracks inside the yarns, was clearly correlated to the first cluster with lower amplitude and lower frequency acoustic events
Contributions of Stepan V Lomov to the research and development of composite materials
No full textThis paper presents a comprehensive review of the scientific and engineering contributions of Prof. Stepan V. Lomov in a career spanning over 3 decades. Starting from his early work on the modelling of dry textiles, different aspects of composite materials have benefited from his inspiring contribution. His wide scientific curiosity drove the research on several topics, covering permeability, forming, damage, fatigue, nano-engineered composites, as well as development of analytical and numerical models at different scales. The paper presents a full spectrum of his scientific career aiming to link his achievements and the future research on composite materials
Contributions of Stepan V Lomov to the research and development of composite materials
No full textThis paper presents a comprehensive review of the scientific and engineering contributions of Prof. Stepan V. Lomov in a career spanning over 3 decades. Starting from his early work on the modelling of dry textiles, different aspects of composite materials have benefited from his inspiring contribution. His wide scientific curiosity drove the research on several topics, covering permeability, forming, damage, fatigue, nano-engineered composites, as well as development of analytical and numerical models at different scales. The paper presents a full spectrum of his scientific career aiming to link his achievements and the future research on composite materials
High- and low-cycle tensile fatigue of all-carbon hybrid quasi-isotropic laminate
No full textIs the pseudo-ductile quasi-static tensile behaviour of all-carbon hybrid composites retained under fatigue loading? This paper addresses this question by examining the low-cycle tensile-tensile fatigue behaviour of a unidirectional carbon laminate and the high cycle fatigue behaviour of an all-carbon fibre hybrid quasi isotropic laminate. The low-cycle fatigue, monitored with the acoustic emission recordings, indicates that the damage pattern observed during the first cycle is maintained in subsequent cycles, albeit with reduced intensity than the initial damage. The high cycle tensile-tensile fatigue performance of an all-carbon fibre hybrid quasi-isotropic laminate revealed that its load-carrying ability is retained for load levels below the pseudo-ductile regime, while it is not beyond the limit of elastic response. Conversely, the
all-carbon hybrid composite maintains its load-carrying ability during strain-controlled fatigue in the pseudo-ductile regime, albeit with a lower stiffnes
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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