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Microplane model for concrete. Part II. Applications on CFRP confined concrete elements
No full textIn the paper the main results of numerical study presented in Gambarelli et al. on concrete elements confined by carbon fiber reinforced polymer (CFRP), are overviewed. Furthermore, preliminary results of numerical simulations performed at mesoscale are presented.
The numerical study is based on a extensively experimental campaign conducted by Wang and Wu on small CFRP-confined concrete columns loaded in uni-axial compression. The specimens are characterized by constant size but different cross-section corner radius (from square to circular cross section). The experimental results clearly demonstrate that CFRP confinement is much less effective in square then in circular cross-section. Several numerical models have been performed at macro-scale and meso-scale to confirm the predictability of the used numerical approach, based on the microplane constitutive law for concrete. In the finite element model carbon fibers (truss FE) are embedded into matrix (solid 3D FE). The same as for concrete, the constitutive law for matrix is also based on the microplane model. It is demonstrated that the numerical model is able to predict behavior of confined concrete columns from the experimental investigations. Therefore, the results of the study confirm the predictability of the used numerical approach
Thin Maple Bilayer Dataset
No full textThis dataset contains measured and derived features of 64 small-scale mapple wood bilayer samples. A wood bilayer consists of two bonded layers with differing material or anatomical properties. When exposed to changes in moisture, the layers expand or contract at different rates, producing curvature. This makes bilayers a fundamental system for studying hygro-mechanical behavior, moisture-driven actuation, and material-informed design.
Each bilayer sample in this dataset was subdivided into 19 segments, enabling segment-level analysis that captures local variations in swelling behavior and curvature response.
The samples were fabricated with four passive–active thickness ratios: 2:8, 3:7, 4:6, and 5:5. These ratios highlight how geometric configuration influences moisture-induced deformation.
All data are provided in CSV format, where each row represents a single segment. Please check the engineering metadata for the definition of each column
Numerical analysis of compressed concrete columns confined with CFRP: Microplane-based approach
No full textThis paper presents the results of numerical studies carried out on concrete columns confined by Carbon Fiber Reinforced Polymer (CFRP) and loaded in uni-axial compression. A numerical simulation of confined columns experimentally tested by [1] is performed for relatively small concrete specimens of constant size but with different cross-section corner radius. The experimental results, reported in terms of axial stress–strain relationships and failure modes, constitute a useful database for the calibration of numerical models. These results clearly demonstrate that CFRP confinement is much less effective in square than in circular cross-sections. Therefore, the influence of the corner radius on the non-uniform stress distribution due to confinement, is numerically investigated using the proposed microplane-based model that takes into account the effect of multi-axial stress states in concrete. The experimental results are used to calibrate and verify the prediction capability of a three-dimensional finite element code (3D FE) that is based on the microplane constitutive law for concrete [2]. In the finite element model carbon fibers are modelled using nonlinear truss elements, while epoxy resin as well as concrete are modelled using microplane-based constitutive law and 3D finite elements. Given that experimental results for unconfined and confined configuration are available for each specimen, the 3D FE concrete model has been preliminarily calibrated on unconfined concrete specimens and then used in the analysis of a confined specimen. It is demonstrated that numerical models can predict behavior of confined concrete columns from the experimental investigations, confirming the predictability of the numerical microplane-based approach used
Microplane model for concrete. Part I. State of the art
No full textThe fundamental concepts of the microplane theory for non-linear modeling of concrete are presented in this paper. The basic idea behind the model is that the relationships between stress and strain are defined on planes of various orientations that represent microstructural damage planes, such as contact layers between aggregate pieces. Starting from the pioneering idea formalized as the slip theory of the plasticity, several models have been proposed in literature with the aim of formulating a general procedure for damage and fracture in concrete, under different loading combinations. The literature models are critically discussed with the aim to introduce an application presented in a companion paper: the application regards CFRP-confined concrete elements modeled at macro and meso-scale
Experimental dynamic testing and numerical modeling of historical belfry
No full textThe experimental characterization of historical bell towers and wall belfries can provide important information for the calibration of numerical models as well as to implement proper restoration strategies. Within this framework, the presented study is concerned with the experimental dynamic assessment of an ancient belfry dating back to 1537. The structure is part of the “SantaMaria in Aracoeli Church” (Rome, Italy), an important heritage construction placed on the summit of the Capitoline Hill, close to the building that hosts the Major’s office. Several field tests have been conducted using accelerometers, and records obtained under different dynamic loading scenarios have been examined.
Moreover, experimental accelerations have been elaborated to estimate the most important modal features of the structure and to validate a finite element model. Field tests have confirmed that severe vibrations are induced when the bells swing, and thus a slight reduction of the swing angle has been suggested in order to provide an immediate and inexpensive benefit to the structure. A new set of field
tests demonstrates that the new swing angle is sufficient to reduce the induced vibrations while preserving the original sound
MESOSCALE MODELING OF CONCRETE: MICROPLANE-BASED APPROACH
Get PDFIn the paper mesoscale model for plain concrete, based on the microplane theory [1] is presented. In the model concrete is treated as a bi-phase composite material, consisting of coarse aggregate and mortar matrix. The presence of interfacial transition zone (ITZ) between the two phases is neglected. The numerical study is based on the experimental tests performed by Wang and Wu [2] on small square concrete columns confined with CFRP and subjected to uniaxial compressive loads. The tests results, reported in terms of axial stress-strain relationships and failure modes, represent useful data base for the calibration of numerical models. In the first step of the study, only the unconfined concrete cylinder (R75) has been modeled at mesoscale. An important aspect of the proposed model is the generation of a random aggregate structure in concrete, which is based on a generation procedure implemented in Matlab R2013b. The mesoscale analysis of the unconfined cylinder is performed by using the finite element code MASA [3]. The constitutive law for mortar is based on the microplane model, while aggregates have been considered linear elastic. It is demonstrated that the numerical model is capable to correctly reproduce the mechanical behavior of the unconfined cylinder, confirming the predictability of the used approach
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
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