Search results for "interface"

A Cohesive-Frictional Interface Model with Frictional Properties Degradation

2009

The paper is devoted to an interface constitutive modeling which couples a cohesive behavior, based on the damage mechanics theory, with a frictional one, defined in a non-associative plasticity framework. By means of a specific interpretation of the damage variable, the formulation follows the transition of the initial sound interface material layer, up to the fully cracked condition. The macrocrack surfaces have initial frictional properties and is subjected to degradation phenomena. Namely, the smoothing and breaking of surface asperities cause a progressive reduction of dilatancy effects and also of the frictional angle. These phenomena are modeled as uncoupled: dilatancy saturation is …

La valeur de la proximité pour une nouvelle interface métabolique

2016

La proximité constitue le noeud conceptuel de la première loi de la géographie de Tobler qui affirme que « tout interagit avec tout, mais deux objets proches ont plus de chance de le faire que deux objets éloignés ». Le concept de proximité ne s’arrête donc pas à une notion purement géographique, mais il acquiert une autre dimension lorsqu’il révèle la composante qualitative des relations au niveau matériel et humain. Bailly (1998) estime que la “proximité” est une condition essentielle pour raccourcir les distances sociales, économiques et culturelles, afin de réduire les tensions et maximiser les interactions entre les acteurs territoriaux.

A nonlinear finite element approach with cohesive-frictional interfaces for mode II Transverse Crak Tension test insight

2016

In many circumstances structural failure modes are driven by the formation and propagation of fractures. For instance in composite laminate structures one of the most worrying condition is delamination, which is an interlaminar progressive fracture. Fracture toughness is the material mechanical parameters which ensure fracture safe condition and it is also an essential parameter for performing nonlinear structural analysis, no matter if based on Fracture Mechanics or by means of Interface Cohesive theories. It is then of paramount relevance to evaluate the critical fracture energy by means of simple and reliable laboratory tests. Several tests are available for the direct determination of m…

A frictional interface model for the propagation of cohesive fracture under cyclic loading

2013

The paper presents an extension of a recent presented mechanical interface model, [1-2], for the description of the smooth cohesive/frictional transition along potentially active cohesive fracture surfaces. The model presented includes the description of internal frictional dissipative mechanisms which are active under combined compressive/sliding loading in either the cohesive process zone, or in the fully fractured interface portion. Moreover, always under compressive/sliding loading conditions, frictional dissipation mechanisms can also develop in the undamaged (or sound) portion of the interface, justified by the circumstance that also at the virgin state in the bonding surface are pres…

Cohesive-frictional interface model with oligocyclic degradation of surfaces roughness

2008

The present work is devoted to the constitutive modelling, through the classical interface kinematical formulation, of the mechanical behaviour of the internal adhesive layers, connecting different bodies. The proposed interface constitutive model couples a cohesive behaviour with a frictional one and it is able to follow the transition from the sound condition to the fully cracked one by means of a specific interpretation of the damage variable. In the fully cracked condition, the dilatancy exhaustion and the frictional strength degradation are also modelled.

An Interface Mechanical Model with a Cohesive to Frictional Transition

2009

A thermodynamically consistent mechanical interface model is presented. The model is based on the interface damage mechanic theory applied in a special fashion such that the interface damage variable is also used as a parameter which drives the continuous and smooth transition from the sound initial cohesive state to the final fully fractured frictional state. Interface damage activation and fictional sliding are promoted by a damage activation function and a Coulomb frictional yielding function. The main features of the model are discussed in details and some numerical results for the material response are shown in monotonic and cyclic loading regimes.

Influence of interaction techniques o n VIMS in virtual environments : estimation and prediction

2014

Understanding oculo-vestibular dynamics during sensory rearrangement in the central nervous system plays an extremely important role in better understanding human perception, and improves the technology in many engineering fields. Besides, the sensory conflict that occurs between ocular, vestibular and proprioception during sensory rearrangement at certain occasions might adversely affect the user performance in a wide variety of domains including flight/car simulators, scale-one 3D systems, large-scale displays, serious games, and so on. Therefore, knowing the condition in which the sensory conflict happens has a great deal of importance. This study aims at understanding the nature of sens…

The Gypsy Database (GyDB) of mobile genetic elements.

2007

In this article, we introduce the Gypsy Database (GyDB) of mobile genetic elements, an in-progress database devoted to the non-redundant analysis and evolutionary-based classification of mobile genetic elements. In this first version, we contemplate eukaryotic Ty3/Gypsy and Retroviridae long terminal repeats (LTR) retroelements. Phylogenetic analyses based on the gag-pro-pol internal region commonly presented by these two groups strongly support a certain number of previously described Ty3/Gypsy lineages originally reported from reverse-transcriptase (RT) analyses. Vertebrate retroviruses (Retroviridae) are also constituted in several monophyletic groups consistent with genera proposed by t…

Il modello di interfase applicato alla meso-modellazione di strutture eterogenee

2010

Exploratory approach for network behavior clustering in LoRaWAN

2021

AbstractThe interest in the Internet of Things (IoT) is increasing both as for research and market perspectives. Worldwide, we are witnessing the deployment of several IoT networks for different applications, spanning from home automation to smart cities. The majority of these IoT deployments were quickly set up with the aim of providing connectivity without deeply engineering the infrastructure to optimize the network efficiency and scalability. The interest is now moving towards the analysis of the behavior of such systems in order to characterize and improve their functionality. In these IoT systems, many data related to device and human interactions are stored in databases, as well as I…