1,721,216 research outputs found
FINITE ELEMENT MODEL FOR THE ANALYSIS OF FLEXIBLY CONNECTED STEEL FRAMES.
No full textA finite element model for the non-linear analysis of flexibly connected steel frames is proposed. The element is regarded as an assemblage of individual parts whose behavior is described in terms of a generalized stresses and strains. Displacements and plastic strain fields are independently modeled. The former are a function of 13 nodal parameters and constitute a typical application of a hierarchical procedure. The latter are modeled over the cross section, along the element and in the six springs located at the ends of the beam. Examples to show the importance of considering the non-linear behavior of the connections in the frame analysis are proposed
Il controllo di accettazione di materiali fibrorinforzati per il rinforzo strutturale
No full textIl presente documento è destinato ai progettisti, ai direttori dei lavori, ai collaudatori ed in generale a tutti gli operatori nel campo del rinforzo strutturale delle costruzioni realizzato mediante materiali fibrorinforzati. Nel testo vengono fornite le indicazioni tecniche per la determinazione ed il controllo delle caratteristiche meccaniche dei materiali fibrorinforzati e viene presentato un sistema da utilizzare in cantiere per la produzione di provini di composito e di adesivo da sottoporre alle prove meccaniche.
Questo lavoro è stato sviluppato nell’ambito delle attività del gruppo di lavoro “Materiali innovativi per la riduzione della vulnerabilità nelle strutture esistenti” del progetto RELUIS coordinato dai proff. Luigi Ascione e Gaetano Manfredi ed a valle dei lavori per la redazione del documento CNR-DT200-2004 ("Istruzioni per la Progettazione, l'Esecuzione ed il Controllo di Interventi di Consolidamento Statico mediante l'utilizzo di Compositi Fibrorinforzati. Materiali, strutture di c.a. e di c.a.p., strutture murarie") di cui costituisce una parte integrativa
Micromechanical model and experimental investigation of glass fiber-reinforced textile laminate
No full textThe mechanical characteristics of a glass woven fabric are examined both experimentally and theoretically. The experiments showed a nonlinear behaviour mainly due to the geometry of the laminate. A three dimensional finite element model was used to study the mechanical behaviour of a unit cell and predict the stiffness and strength of the laminate. The 3D model considers the fabric thickness, the yarn orientation and the fibre volume fraction and can be
extended to include nonlinear effects and delaminations
Numerical model for the mechanical properties of multi-axial multi-ply stitched fabric composites, A
No full textTwo-scale modeling for failure analysis of textile composites
No full textA two-scale homogenization technique is presented to evaluate the mechanical properties of woven textile composites. The numerical approach is founded on the main assumption of periodic distribution of the reinforcements in the composite at two different scale. The first scale concerns the warp and weft yarns while the second regards a representative volume of the woven textile laminate with homogenized yarns. The main aim is to predict the macroscopic behavior until failure of textile composites. The procedure is validated against experimental results
Numerical tools for design and assessment of monofilament technical textiles
No full textA numerical approach based on two scale modelling for the prediction of the mechanical prop-erties of technical textile structures is detailed in this paper. The first scale deals with the predic-tion of the mechanical behaviour of a plane weave monofilament textile by the numerical analysis of a Representative Volume. The numerical analysis of the entire textile component is performed, in the second modelling, employing the textile mechanical behaviour obtained in the first step. The first scale analyses (textile scale) are validated by experimental results including uniaxial and biaxial tensile tests. The second scale analyses deal with a textile cylindrical com-ponent employed in a screen printing technique
Linee guida per la qualificazione ed il controllo di accettazione dei materiali compositi fibrorinforzati a matrice polimerica (FRP) per il rinforzo strutturale di strutture esistenti
Full text linkMacroscopic properties of woven fabric composited by 3d numerical analysis
No full textThe mechanical properties of woven fabric composites could be predicted by two different approaches (1). The first is based on the lamination theory (see e.g. (2)) and is usually employed for approximated predictions of thermo-mechanical characteristics. The second gathers numerical refined finite element models (see e.g. (3)).
In this work an approach belonging to the latter group is described. The main assumption is the periodic distribution of the reinforcements in the composite. Therefore the theoretical concepts of the homogenization theory for periodic media are exploited (see e.g. (4)).
The approach is based on two levels of homogenization. The first level concerns the warp and weft yarns. They are considered as unidirectional fiber reinforced composites characterized by a fiber volume fraction equal to the packing density. The second homogenization level is performed on a representative volume of the woven composite. It is singled out and modelled by a three-dimensional finite element mesh. The assumed material
periodicity is taken into account by kinematic boundary conditions.
The necessary input parameters are limited to the geometry of the reinforcement and to the mechanical properties of the matrix and fibers
Steel cord-rubber composites: mechanical properties by a numerical homogenization method
No full textIn this paper a numerical micromechanical method for the determination of the mechanical properties of steel cord-rubber composites is presented. The approach is based on the finite element method assuming a periodic distribution of the reinforcements in the composite. The theoretical concepts of the homogenization theory for periodic media are exploited. The determination of the global (or
macroscopic) mechanical behaviour of the heterogeneous material is reduced to the analysis of a Representative Volume (RV). The numerical predictions are validated against experimental
investigations on single and multi-layers specimens. Different steel cords, having a wide range of orientation, and two types of rubber are considered
- …
