1,720,956 research outputs found
Fatigue damage in carbon fibre reinforced aluminium alloy laminates
No full textThis research seeks to develop a unified model for fatigue crack and damage growth processes in a hybrid laminate. The progress of damage in a carbon fibre reinforced aluminium alloy laminate has been monitored, while simultaneously the strain within a defined area in the vicinity of the crack has been measured directly, by means of fibre optic sensors. Some preliminary finite element modelling results are presented. It is shown that the range of the stress intensity factor remains the most significant parameter for characterising fatigue crack growth. A stress intensity factor, modified to account for the changing compliance introduced by fibre-bridging and delamination, was found to be appropriate for these materials
Characterisation of fatigue crack growth and related damage mechanisms in FRP-metal hybrid laminates
No full textNumerical simulation of fatigue failure in carbon fibre reinforced aluminium alloy laminates
No full textHybrid laminates typically consist of alternate layers of fibre reinforced plastic and aluminium alloy. Developed for fatigue critical aerospace applications i.e. fuselage and lower wing skins, the hybrid laminates are orthotropic materials with lower density and higher strength compared to the alloy monolith. A remote sensing system reliant upon fibre optic technology has been developed to monitor the strain field encountered across composite laminae. This fibre optic system has been applied initially to the problem of characterising delamination zone development about a fatigue crack initiated at a through thickness fastener hole. Delamination measurements obtained using an in-situ ultrasonic C-scanner have been utilised in numerical simulations of the fatigue failure process and the data compared with measured strain profiles
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
Damage assessment across hybrid laminates using an array of embedded fibre optic sensors
No full textHybrid laminates typically consist of alternate layers of fibre-reinforced polymer and aluminium alloy. Developed primarily for fatigue critical aerospace applications, the hybrid laminates are orthotropic materials with lower density and higher strength compared to the aluminium alloy monolith. One of the damage mechanisms of particular interest is that of fatigue crack growth, which for hybrid laminates is a relatively complex process that includes a combination of delamination and fibre bridging. To facilitate the development of a unified model for both crack and damage growth processes, a remote sensing system, reliant upon fibre optic sensor technology, has been utilised to monitor strain within the composite layer. The fibre optic system, with capacity for sub microstrain resolution, combines time domain multiplexing with line switching to monitor continuously an array of Bragg grating sensors. Herein are detailed the findings from a study performed using an array of 40 sensors distributed across a small area of a test piece containing a fatigue crack initiated at a through-thickness fastener hole. Together with details of system operation, sensor measurements of the strain profiles associated with the developing delamination zone are reported
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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