Search results for "face"
showing 10 items of 11436 documents
Simulation of Fatigue Delamination Growth in Composites with Different Mode Mixtures
2007
A numerical model, obtained by implementing a cyclic damage model in the framework of an interface element, is here proposed to reproduce the crack growth in laminated composites subjected to cyclically repeated loads. This model, which differs from the few studies in the literature on the topic, applies not only to single fracture modes but also to mixed modes, and to constant or variable crack growth rates. The applied load (in terms of force or displacement) is assumed to oscillate between a minimum and a maximum constant value. The Paris curve can be reproduced with accuracy once some parameters in the numerical model are tuned with experiments. These parameters are preliminarily found…
Vers une assistance informatisée au diagnostic de la qualité ergonomique d'interfaces
2000
International audience; Notre objectif ici est d'encourager les concepteurs à s'intéresser aux usages de leur produit en prenant davantage en compte les facteurs humains dans la phase de test qui est souvent focalisée sur les aspects techniques. L'idée dans cette étude est donc de faciliter le recours aux utilisateurs comme source d'évaluation lors des tests de conception en apportant aux concepteurs un environnement logiciel de test pratique à mettre en œuvre pour faire évaluer leurs propres produits par des utilisateurs. Nous avons mené deux expériences de nature à explorer la faisabilité de ce projet.
Il calcestruzzo poroso per il miglioramento delle condizioni di stabilità dei pendii sede di falda idrica
2022
Reduction of pore water pressures is a useful strate-gy to improve the stability conditions of slopes. Deep draining trenches can be used for this scope. For the realisation of deep trenches, the usual con-ventional construction techniques are not adequate and the use of adjacent vertical panels, built by means of the methods well established for dia-phragm walls, is necessary. However, unbonded ma-terials (i.e. gravels) cannot be used, since the excava-tion of a panel adjacent to already built ones will cause instability. For this scope a bonded material such as the pervious concrete can be used. It must have high permeability, filtering capacity in order to prevent the internal erosion of…
La resistenza di interfaccia calcestruzzo poroso-terreni a grana fina per il consolidamento di pendii mediante trincee drenanti profonde
2022
Le trincee drenanti profonde rappresentano uno dei metodi più efficaci per la mitigazione del rischio da frana, in pendii con falda idrica. Esse sono realizzate mediante pannelli o pali secanti. Il riempimento è costituito di calcestruzzo poroso o materiale granulare. Se le trincee sono adeguatamente “innestate” nel terreno stabile e il materiale di riempimento ha sufficiente resistenza e rigidezza come il calcestruzzo poroso, si ha ulteriore in-cremento di resistenza a taglio per effetto shear keys, oltre a quello derivante dalla riduzione delle pressioni in-terstiziali. L’incremento di resistenza è dovuto sia alla resistenza all’interfaccia calcestruzzo–terreni sia a quella intrinseca del…
Distribution and generation of traps in SiO2/Al2O3 gate stacks
2007
In this work we combine charge-pumping measurements with positive constant voltage stress to investigate trap generation in SiO2/ Al2O3 n-MOSFET. Trap density has been scanned either in energy or in position based on charge-pumping (CP) measurements performed under different operating conditions in terms of amplitude and frequency of the gate pulse. Our results have revealed that the traps are meanly localized shallow in energy level, deeper in spatial position and they are mostly generated near the Si/SiO2 interface. (C) 2007 Elsevier Ltd. All rights reserved.
La lecture numérique
2015
International audience; La lecture numérique n’est pas équivalente à la lecture sur papier. Depuis plus d’une vingtaine d’années, les données montrent un déficit général de la perception et de la compréhension, lié à l’emploi des supports électroniques. Ce problème est plus que jamais d’actualité avec le développement croissant des réseaux informatiques, des bibliothèques virtuelles, des logiciels multimédia, des liseuses et des tablettes qui impliquent de nouveaux comportements et de nouvelles compétences du lecteur. L’ouvrage synthétise les découvertes et les développements théoriques apportés par la psychologie cognitive et l’ergonomie cognitive dans le domaine de la lecture numérique. T…
An Interface Model for the Analysis of Anisotropy of Friction and Wear of Contact Surfaces
2008
Effective reference and current integration for large displacement interface
2016
The most common interface formulations proposed in literature are generally based on the restrictive hypothesis of small strains and small displacements and, even though their application to geometrically nonlinear problems is of paramount interest, only few contributions are available in literature. Motivations are probably due to the difficulties encountered on such formulation, as already mentioned by several authors. A pioneering formulation is the finite displacement three-dimensional interface developed by Ortiz and Pandolfi in [1], where normal and tangential traction components are evaluated with respect to the middle surface in the current configuration, producing a non-symmetric g…
Interface model for the nonlinear analysis of blocky structures of ancient Greek temples
2010
The presence of singularity surfaces with reference to the displacement field is a characteristic of a number of structural systems. Strong discontinuities are present in old masonry structures where dry joints connect the blocks or the mortar ageing suggests to neglect the adhesion properties. These structures cannot be considered a continuum but rather an assembly of blocks. These discontinuous structures could be modelled as an assembly of blocks interacting trough frictional joints whose mechanical behaviour is described by appropriate interface laws. In the present work an interface model present in literature is adopted, the double asperity model, which has been implemented in a stand…
Analyse semio-ergonomique d'interfaces multimédias
2002
Communication affichée; National audience; Cet article présente une démarche visant à combiner les méthodes d'analyses de produits multimédia utilisées dans deux champs différents : la sémiologie et l'ergonomie. Ces méthodes complémentaires donnent des résultat dans trois principales directions d'analyse. La capacité fonctionnelle du produit, sa facilité d'utilisation et son esthétique. Dans ce contexte, des méthodes d'analyse des signes qui composent les message permettent d'évoquer des hypothèses qui sont validées ou non à l'aide des méthodes d'observation en situation.