1,721,066 research outputs found
On fatigue limit in the presence of notches: classical vs. recent unified formulations
No full textClassical formulations for the fatigue strength reduction factor of notched specimen, Kf, (such as those by Neuber, Peterson, Heywood) were developed long time ago and have found some success by introducing a material constant (dependent on the tensile strength only) in order to take into account the problem of notch sensitivity. However, being empirical fitting equations, they have serious limitations when their asymptotic behaviour is considered, or when the empirical constants are not directly calibrated with experiments. This is shown in this work by using example data taken from the literature for various steels and alloys, and various notch sizes and shapes.Furthermore, although the material constants can be modified to include fatigue threshold dependence (satisfying the requirements of fracture mechanics), only the Neuber formula has a correct functional form in the entire range of notch sizes and shapes, and indeed appears to be sufficiently conservative in the range of data considered.Improved accuracy is found with a more recent empirical criterion due to Atzori and Lazzarin based on the Smith and Miller classification of notches, and with a new criterion here obtained by making consistent the Atzori and Lazzarin with the Luká–Klesnil, having a sound interpretation in terms of self-arrested cracks ahead of a rounded notch for which the Creager–Paris stress field is valid. A large number of experimental data are taken from the literature to compare the accuracies of the various criteria
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
A generalized Paris' law for fatigue crack growth
No full textAn extension of the celebrated Paris law for crack propagation is given to take into account some of the deviations from the power-law regime in a simple manner using the Wohler SN curve of the material, suggesting a more general "unified law". In particular, using recent proposals by the first author, the stress intensity factor K(a) is replaced with a suitable mean over a material/structural parameter length scale Delta a, the "fracture quantum". In practice, for a Griffith crack, this is seen to correspond to increasing the effective crack length of Delta a, similarly to the Dugdale strip-yield models. However, instead of including explicitly information on cyclic plastic yield, short-crack behavior, crack closure, and all other detailed information needed to eventually explain the SN curve of the material, we include directly the SN curve constants as material property. The idea comes as a natural extension of the recent successful proposals by the first author to the static failure and to the infinite life envelopes. Here, we suggest a dependence of this fracture "quantum" on the applied stress range level such that the correct convergence towards the Wohler-like regime is obtained. Hence, the final law includes both Wohler's and Paris' material constants, and can be seen as either a generalized Wohler's SN curve law in the presence of a crack or a generalized Paris' law for cracks of any siz
NORMALIZATION OF LOAD AND CLEARANCE EFFECTS IN BALL-IN-SOCKET-LIKE REPLACEMENTS
No full textA normalizing loading parameter useful in summarising the mechanical response ofplane pin-in-plate-like contacts is extended to axisymmetric ball-in-socket-like contacts. Anexample addressing a compliant layered artificial hip joint is presented, and the usefulness ofthe normalizing loading parameter is evidenced
Le nuove frontiere della rivoluzione digitale nella medicina legale il bareme digitale: un cambio di passo epocale
No full textIl Barème Digitale è stato pensato inizialmente come uno strumento di ausilio del lavoro del medico in una logica di valutazione assistita e integrata rispetto al sapere e alle competenze del professionista per porsi strada facendo un obiettivo più alto, ovvero, grazie all’intelligenza artificiale e all’uso di strumenti informatici avanzati, di poter essere l’effettivo, reale ed autonomo mezzo di valutazione degli handicap in ambito infortunistico, previdenziale e sanitario, in cui il ruolo del medico sia quello di un regolatore/moderatore del sistema. Con il Barème Digitale, non solo si avrà una semplificazione dei criteri di valutazione e una riduzione dei tempi senza penalizzarne la qualità e l’attendibilità ma si giungerà, finalmente, alla stima dei pregiudizi alla persona con sistemi scientifici e verificabili e non più con una procedura alimentata dalla confluenza di osservazioni e di apprezzamenti empirici: la discrezionalità che ha caratterizzato l’attività medico-legale può essere superata nell’interesse non solo del singolo, ma anche della collettività, tenuto conto dei riflessi economici che ogni scelta medico legale comporta
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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