1,720,969 research outputs found
Discrete rotating links model for the nonlinear torsion-shear behaviour of masonry joints
No full textThe numerical modelling of the torsion behaviour of masonry block interfaces is a key aspect for the assessment of the out-of-plane response of masonry walls. Nevertheless, it still represents a challenging computational issue due to the high non-linear coupling between the torsion and other internal forces (shear, bending moment and axial load), which rigorously requires the adoption of complex 3D non-linear constitutive laws. Some limit analysis-based approaches, proposed in the specific literature, represent efficient and reliable numerical tools for predicting the ultimate states of brick masonry structures subjected to combined in-plane and out-of-plane actions, while involving complex torsion loads and combined actions. This paper originally introduces a simplified discrete inelastic interface able to simulate the non-linear torsion-shear behaviour of masonry contact joints, within the context of static incremental analysis. The more general mechanical behaviour of the interface is ruled by six degrees of freedom and is governed by four rotating links (RL), whose actual orientation is updated during the step by step analysis, by taking into account the current position of the twisting centre of the interface. The incremental torsion-shear capacity curve and the corresponding ultimate domains obtained by the proposed model are compared with the ultimate load limit analysis predictions and with some experimental data available in the literature. The results highlight the ability of the new discrete interface to effectively reproduce the full non-linear behaviour of masonry contact interface subjected to different loading combinations
Families of beams with a given buckling spectrum
No full textThis paper is concerned with constructing families of
Euler-Bernoulli beams which have exactly the same sequence of
buckling loads of a given beam. The result is valid under the
assumption of Pinned-Pinned, Pinned-Sliding and Sliding-Sliding
end conditions. The analysis is based on a reduction of the
buckling problem to an eigenvalue problem for a class of strings,
and on constructing isospectral strings via a Darboux lemma
OUT-OF-PLANE RESPONSE OF MASONRY CHURCH FACADES INCLUDING P-DELTA EFFECTS
No full textOut-of-plane rocking mechanisms represent one of the major causes of damage and failure for unreinforced masonry buildings, monuments and churches leading to significant economic and social losses every year in many regions throughout the world. Due to their slenderness, masonry walls subjected to rocking mechanisms can show large displacements before the complete overturning. Therefore, seismic analyses should consider geometrical nonlinearities, requiring more complex formulations and increasing the computational effort.
This paper applies a recently proposed P-Delta formulation of the discrete macro-element method (DMEM) to analyse the seismic behaviour of masonry façades interacting with lateral walls. The model accounts for geometrical nonlinearities considering the P-Delta effects by updating the load vector at each step of the analysis, avoiding assembling and updating the geometrical stiffness of the system. In addition, the capability of the model to describe the coupled in-plane and out-of-plane wall responses allows for describing spatial failure mech-anisms. The presented study aims at quantifying the role of the P-Delta effects in conjunction with the cohesive-friction connections between the façade and lateral walls on the ultimate rocking of the external façade. These effects are here investigated through pushover analyses on a church façade. The analyses are conducted on a global model, accounting for brick interlocking, and on a simplified model, including only the façade where ad hoc calibrated non-linear links simulate the interaction with the lateral walls. The results show that geometrical nonlinearities affect the façade’s response even at relatively low-magnitude displacements, with increasing influence as the quality of the façade-to-lateral-walls connections reduces
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
Numerical Investigation of a Medieval Masonry Arch Bridge Based on a Discrete Macro-element Modeling Approach
No full textDispelling 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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