1,721,111 research outputs found
Redundancy and robustness of brittle laminated plates. Overlooked aspects in structural glass
No full textAssessing method of shear strength between old to new concrete interface under cycling loading
No full textThe retrofitting of the existing RC structures with added concrete layer crossed by post- installed rebars is strongly related to the behavior of the interface between the new and the old concretes. The overall strength of the connection depends on several mechanisms such as dowel action, friction between the two concrete layers, and type of action. In the past, attention was given to understand these mechanisms under monotonic loading, and only limited research has been devoted to investigate the cyclic behavior of concrete layers casted at different times. In this paper common experimental test set-ups (typical push-off tests and two tests configurations that allow the application of reversed actions) have been numerically analyzed to select the most reliable configuration to assess the cyclic behavior of concrete interface. Finally, the most promising set-up has been experimentally validated considering two different boundary conditions, to define the most appropriate test configuration to assess the performance at the interface under cyclic action. The results highlight that the ratio between cyclic and monotonic strength is lower than one and that cycles at the same slip level show a progressive strength reduction. On the basis of these outcomes, it seems that static assessment cannot be assumed in practical cases when cyclic actions are crucial, and a proper evaluation of cyclic performances is needed
Structural Optimization of Laminated Annealed Glass
No full textLaminated glass, made by bonding glass plies together through polymeric interlayers, is a redundant system that allows for stress redistribution after partial failure. This study analyzes how the structural safety level of laminates made by two or three plies of annealed glass varies with the ratio between the thicknesses of the layers and their placement in the package. The probability of failure of laminated glass elements, in which the layers are arranged in different order, is statistically analyzed under gust wind loads, accounting for all the potential sequences of breakage for the plies. The gain obtainable from a tailored composition is quantitatively estimated through specific safety factors to be used in semiprobabilistic (Level I) design and calibrated through comparison in paradigmatic case studies with full-probabilistic (Level III) methods. Optimal laminated packages are thus determined as a function of the target probability of failure classified according to four distinct classes of consequences for malfunction or failure
The effect of size and stress state on the strength of architectural glass. Experiments versus theory
No full textThe multi-scale approach in the statistical evaluation of the macroscopic strength of annealed glass for architectural applications indicates a close correlation with the population of surface microcracks present in the glass sheets. The theory predicts a dependence of the strength capacity on the size of the glass element and on the state of stress acting on it. To investigate this effect, an experimental campaign has been conducted on samples of three different sizes, tested in a ring-on-ring apparatus. Data were re-normalized according to statistics of the Weibull type and re-scaled to account for the phenomenon of static fatigue. For small- and medium-size specimens, the results are in agreement with the prediction of Weibull statistical theory, according to which the larger the specimen, the greater the probability of finding cracks of critical size and, consequently, the lower the macroscopic strength on a statistical basis. On the other hand, quite surprisingly, large samples show an opposite trend. Since the state of stress is not uniform and equibiaxial in the large specimens, on the contrary to what happens in the small and medium size ones, this finding suggest a revision of classical approach based on linear elastic fracture mechanics and its correlation with the weakest-link-in-the-chain rationale in the evaluation of the mechanical properties of brittle materials such as glass
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
Experimental results of a national technical assessment procedure on commercial FRP for structural strengthening: wet-lay-up systems
Full text linkThe paper shows the results of a large experimental activity for the qualification of wet-lay-up FRP products for structural repair and/or strengthening, required by the Italian national approval authority. The qualification procedure and the correspondent design rules are described in national guidelines. The analysis of the experimental results of a large number of qualification tests allows to highlight some aspects in the national procedure that could be addressed in a future revision of the guidelines. In particular, statistical analyses were carried out in order to assess the most suitable probabilistic models able to describe the experimental distribution of the tensile strength and the Young’s modulus of FRP wet-lay-up materials falling in the same class. The analyses were developed with reference to both ordinary and artificial environmental conditions. Nevertheless the paper is focussed on the case of wet-lay-up FRP materials, it can be considered exemplary of a problem common to other products
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