1,721,030 research outputs found
Uncertainty of Estimated Rainflow Damage in Stationary Random Loadings and in Those Stationary per partes
Full text linkThe uncertainty of rainflow fatigue damage is evaluated for stationary loadings and for non-stationary switching loadings with a finite number of stationary states. The approach is based on confidence intervals constructed after direct analysis of stress-time histories. The accuracy of confidence intervals is verified first by numerical simulations, and then by experimental data measured in a mountain bike traveling under various driving and road surface conditions, yielding stationary and non-stationary switching loadings. Stationarity and non-stationarity of loading records is checked by a statistical method (run test). In experiments, a small set of records (validation set) is also collected and used to approximate the expected damage, which serves for verification purposes. Not only do numerical and experimental results confirm the correctness of the proposed confidence interval for damage, but they also emphasize its usefulness in real engineering applications
A probabilistic fatigue model based on nonlinear Kohout-Věchet function: Application to 42CrMo4+QT steel
No full textThis paper presents a fatigue model designed to provide probabilistic-stress-life (P-S-N) curves at any probability level. Grounded in the Weibull probabilistic model's framework, the model describes two scenarios: P-Case A, which considers deviations in stress, and P-Case B, centered on deviations in cycles to failure from the median S-N curve. A significant aspect of the proposed model is the incorporation of the Kohout-Vechet function as the representative median S-N curve, allowing for the Kohout-Vechet P-S-N curves across any probability level. To demonstrate the model's practical relevance, an experimental example focused on specimens made from 42CrMo4+QT steel and subjected to push-pull loading is explored. Not only do the results show the robustness of the model but they also emphasize the role of the characteristic P-S-N curves, especially at lower probability level, in assuring the safety of engineering components
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
Editorial: Structural integrity and durability of engineering materials and components
Full text linkEngineering components and structural details may be subjected in service to quite
different loading conditions: high-cycle or low-cycle fatigue (with constant or variable
amplitudes), static loadings and/or overloads, vibrations, creep, stress corrosion–just to cite a few examples. Whatever the loading condition, an assessment of the structural integrity for a structural detail must ensure an adequate safety margin against unexpected failures with potential catastrophic consequences. This goal is pursued by the use of theoretical, numerical and experimental approaches, often combined. For example, laboratory tests to estimate fundamental material properties, or full-scale tests to validate a finite element analysis implementing suitable strength models. Most often, scientific research deals with each of these areas separately, by proposing unconventional strength criteria, developing numerical techniques, or testing the durability of specific categories of traditional and advanced materials.
The four papers of this Research Topic address some of the above-mentioned
Research Topic by means of theoretical and/or experimental studies that cover
application areas from mechanical to civil engineering
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