Search results for "CONTACT"
showing 10 items of 1003 documents
Numerical analysis of masonry structures via interface models
2001
The present paper is devoted to the theoretical formulation and numerical implementation of an interface model suitable to simulate the behavior of mortar joints in masonry structures. The interface laws are formulated in the framework of elasto-plasticity for non-standard materials in order to simulate the softening response which occurs along the decohesion process in presence of shear and tension tractions. A variable material dilatancy parameter is introduced together with a further geometrical dilatancy related to the roughness of contact surfaces after joint fracture. An asperity model is adopted with the aim to describe the evolution of the contact surface shape during the loss of co…
An interface model for analysis of deformation behaviour of discontinuities
1996
An interface constitutive model is presented accounting for slip and sliding effects and also for dilatancy phenomena. The microslip effects are described by considering spherical asperity interaction with variation of contact area and generation of progressive or reverse slip zones. The incremental constitutive equations are derived with proper memory rules accounting for generation and annihilation of particular slip zones during the process of variable loading. It is further assumed that sliding of spherical contacts occurs along large asperities whose slope varies due to the wear process. The predicted shear and dilatancy curves are shown to provide close quantitative simulation of avai…
BIEM-based variational principles for elastoplasticity with unilateral contact boundary conditions
1998
The structural step problem for elastic-plastic internal-variable materials is addressed in the presence of frictionless unilateral contact conditions. Basing on the BIEM (boundary integral equation method) and making use of deformation-theory plasticity (through the backward-difference method of computational plasticity), two variational principles are shown to characterize the solution to the step problem: one is a stationarity principle having as unknowns all the problem variables, the other is a saddle-point principle having as unknowns the increments of the boundary tractions and displacements, along with the plastic strain increments in the domain. The discretization by boundary and i…
The symmetric boundary element method for unilateral contact problems
2008
Abstract On the basis of the boundary integral equation method, in its symmetric formulation, the frictionless unilateral contact between two elastic bodies has been studied. A boundary discretization by boundary elements leads to an algebraic formulation in the form of a linear complementarity problem. In this paper the process of contact or detachment is obtained through a step by step analysis by using generalized (weighted) quantities as the check elements: the detachment or the contact phenomenon may happen when the weighted traction or the weighted displacement is greater than the weighted cohesion or weighted minimum reference gap, respectively. The applications are performed by usin…
Objective assessment of the effect of pupil size upon the power distribution of multifocal contact lenses
2017
AIM: To analytically assess the effect of pupil size upon the refractive power distributions of different designs of multifocal contact lenses. METHODS: Two multifocal contact lenses of center-near design and one multifocal contact lens of center-distance design were used in this study. Their power profiles were measured using the NIMO TR1504 device (LAMBDA-X, Belgium). Based on their power profiles, the power distribution was assessed as a function of pupil size. For the high addition lenses, the resulting refractive power as a function of viewing distance (far, intermediate, and near) and pupil size was also analyzed. RESULTS: The power distribution of the lenses was affected by pupil siz…
Plural Paths for Interweaving Diversity in Palermo
2008
The most recent ethnic movements and cultural contacts are modifying the city nature all over the world, and in these years even the most fringe European areas are witnessing an increase in cultural and social mixité. Currently we can assert that the city is not an unitary system any more, instead is composed of multiple (often non-homogeneous) groups which express new forms and demands of space use. In this context of fast changes, the various ethnic groups coming to European cities are not the only stakeholders of diversity. There are also cultural groups which have remained separate until now, each one rooted in a restricted part of the city, according to models that are obsolete nowaday…
Formation et médiation en r(é)volution numérique : enjeux communicationnels de l'intégration du digital learning dans les centres de contact
2018
This thesis is part of the information and communication sciences, under the nail of evolution, of the media. Information and communication technologies (ICTs) have invested in our everyday life, globalized digitization and connected objects have considerably modified the practices and uses in the training services of companies, especially in terms of interpersonal communication and digitized pedagogical relations. This work of thesis aims to accompany the trainers of the contact centers on the processes, the conditions of success and the stakes of the integration of the e-learning. By analyzing in what ways new training practices, notably via online platforms, generalized digitization have…
Bank competition and multimarket contact intensity
2021
Abstract This paper analyzes the effect of multimarket contact on bank competition. We propose a completely new multimarket contact indicator that not only considers the existence of contacts between banks, but also their intensity, by analyzing the strength–weakness position of banks in terms of branch numbers in comparison to their rivals in the markets where they coincide. We test the new indicator empirically in the context of the Spanish banking sector. The main results suggest a negative relationship between market power and the number of multimarket contacts, rejecting the hypothesis of tacit collusion in the Spanish banking sector. However, the result changes completely when we cons…
Institutional distance and international networking
2017
We focus on how small- and medium-sized enterprises (SMEs) adapt to differences in institutional logics (values, beliefs, and rules) in their networking when they enter an institutionally distant market. We address gaps in the literature, relating to the role of institutional logics in SME internationalization, and how institutional distance affects the formation of network ties. We show how the social interaction involved in internationalization is embedded in the institutional logics followed by partnering actors. Specifically, we demonstrate how institutional distance may constrain the networking activities of SMEs and identify practices that may support successful internationalization. …
Design and Implementation of Deep Learning Based Contactless Authentication System Using Hand Gestures
2021
Hand gestures based sign language digits have several contactless applications. Applications include communication for impaired people, such as elderly and disabled people, health-care applications, automotive user interfaces, and security and surveillance. This work presents the design and implementation of a complete end-to-end deep learning based edge computing system that can verify a user contactlessly using &lsquo