1,720,994 research outputs found
A numerical investigation of structure-property relations in fibre composite materials.
No full textA multifield continuous model is adopted to investigate the mechanical behaviour
of heterogeneous materials made of short, stiff and tough fibres embedded in a
more deformable matrix. This continuum accounts for the presence of internal
structure by means of non-standard field descriptors. The constitutive relations,
obtained by a multiscale approach linking the material description at different scales,
depend on the geometry and the arrangement of the internal phases and include
internal scale parameters, which allow taking into account size effects. A multiscale
finite element technique has been used for obtaining the numerical solution of the
multifield and the corresponding Cauchy model. The numerical results obtained on
a sample fibre reinforced composite show the effectiveness of the former in pointing
out the influence of the size, the shape and the orientation of the fibres on the gross
behaviour of the material
Multiscale modeling and simulation of fiber Reinforced Composites: macroscopic properties vs. microscopic features
No full textThis paper focuses on the modeling of a fiber-reinforced composite material, by means of a micropolar continuum.
The macroscopic constitutive relation is obtained by a multiscale procedure, bridging the continuum with a lattice-type micromodel.
Numerical results show the influence of the morphological and constitutive micro-features on the macroscopic response
Multifield continuum modelling for materials with lattice microstructure
No full textThe response of a composite material made of strong fibres embedded
in a deformable matrix is investigated using a multiscale approach. At the microscopic
level the body is described as a lattice system while at a the macroscopic
level a multifield continuum is derived using a energy equivalence criterion. This approach
provides a mechanically funded basis to build up equivalent continua endowed
with the parameters suitable for describing different microstructures. Numerical analyses
show the effectiveness of the multifield modelling with respect to the classical
continuum modelling
Multiscale modelling of materials by a multifield approach: microscopic stress and strain distribution in fiber-matrix composites
No full textA recently developed multiscale, multifield model is used to study the elastic response of a fiber-reinforced polymer composite material under different loading conditions. The multifield model is based on the theory of microstructured continua, and allows the introduction of microstructural variables (in this case the local microfiber orientation) within a standard continuum model. The numerical solution is implemented in a finite element approach. By simulated loading tests on a model system, we show that the multifield model goes well beyond the conventional anisotropic Cauchy solution, and can effectively incorporate the dependence of the elastic response on (i) an internal length scale, representing the actual fiber length, and (ii) the local fiber orientation
Multiscale Modeling of Composite Materials by a Multifield Finite Element Approach
No full textWe present a multiscale model for composite materials based on the theory of multifield continua. Such a model includes additional fields besides the standard stress and deformation, allowing representing microstructures in a continuous medium. The multiscale model was implemented in a new finite element code, MUSCAFE. Numerical examples describing a fibre-reinforced composite material with a porous (microcracked) elastic matrix are presented. We firstly discuss an uncoupled model, in which the microstructural relaxation does not influence the macroscopic displacement field. Then, the first stage of development of a fully-coupled model is described. Here appropriate coupling tensors describe the interaction between displacement and microstructure at the macroscopic level, thereby reflecting the microscopic interaction laws between microstructural elements and the matrix. The latter laws are derived by a combination of theoretical assumptions and atomistic molecular dynamics simulation
Int. Symposium Multiscale and Multiphysics Computational Methodologies for Complex Materials, IV European Conference on Computational Mechanics Solids, Structures and Coupled Problems in Engineering - ECCM, Paris, May 16-21.
No full textComputational Mechanics: Solids, Structures and Coupled Problems in Engineerin
Simulazioni multicampo di sistemi continui strutturati tramite un approccio ad elementi finiti
No full textSi presenta un codice di calcolo che consente di svolgere analisi ad elementi finiti di problemi di elasticità piana, in regime lineare o non lineare, per continui ‘multicampo’. Tali continui sono dotati di descrittori di campo rappresentativi delle proprietà interne di materiali complessi. Alcune analisi preliminari confermano risultati ottenuti analiticamente per tali modelli
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
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