Conception des pseudo-articulations à col paraboique

in Agiuzoul, Mohammed (Ed.) 11ème Congrès de Mécanique - Actes du Congrès (2013, April)

The elastic behaviour of parabolic notch hinges submitted to the classical sollicitations of a beam is studied. For each sollicitation, an analytical solution is given first. Its asymptotic expression for ... [more ▼]

The elastic behaviour of parabolic notch hinges submitted to the classical sollicitations of a beam is studied. For each sollicitation, an analytical solution is given first. Its asymptotic expression for very narrow hinges is then obtained and finally,, an approximate factor relating the exact solution to the asymptotic one is proposed. [less ▲]

Mémento de conception mécanique

Book published by DEBONGNIE (JEAN-FRANCOIS) (2013)

Normal numbers. Tolerances. Alloy designation. Antifriction bearings. Journal bearings. Assembling of a shaft and a hub. Bolts. Welds. Riveted joints. Shafts. Fatigue. Hertzian contacts. Wear. Belts ... [more ▼]

Normal numbers. Tolerances. Alloy designation. Antifriction bearings. Journal bearings. Assembling of a shaft and a hub. Bolts. Welds. Riveted joints. Shafts. Fatigue. Hertzian contacts. Wear. Belts. Gearings. Illustrated lexicon. [less ▲]

Comportement élastique des articulations flexibles à col elliptique

Conference (2012, May 04)

We present here amodel for the prediction of the elastic behaviour of elliptic notch hinges, including bending and shear in both planes, stretching and torsion. In a first step, an exact solution is ... [more ▼]

We present here amodel for the prediction of the elastic behaviour of elliptic notch hinges, including bending and shear in both planes, stretching and torsion. In a first step, an exact solution is established in the frame of the beam theory, making use of Sommerfeld's change of variable, which is well known in the lubrication theory. The second step is the deduction of the asymptotic solution for very thin hinges. Finally, and yhis is the most original part of our presentation, a simple corrective factor is deduced numerically, which enables to pass from the asymptotic solution to the exact one with a fair approximation in the practical range of thicknesses. <the simplicity of the obtained model has no equivalent in the literature, which is specially useful at the design stage. [less ▲]

Calculs d'endurance par similitude

in Zenasni, Mohamed (Ed.) 10 ème Edition du Congrès International de Mécanique (2011, April)

The essential difficulty of the design against fatigue lies in the fact that the fatigue strength depends not only on the material, but also on the scale. It is true that models do exsist from long, but ... [more ▼]

The essential difficulty of the design against fatigue lies in the fact that the fatigue strength depends not only on the material, but also on the scale. It is true that models do exsist from long, but they are limited to those geometries with known stress concentration factor and known gradient. Now, there exist a lot of problems for which these two parameters are not known, the most obvious being the press-fitted assembly. Such cases will be called unpredictable notches. The aim of the present communication is to present a similarity method leading to a liable prediction of the behaviour of such notches, from partial experimental data. Comaparing the results of the present method to publishes results, a fair agreement is found. [less ▲]

Travaux du LTAS (Méthodes de Fabrication) en micromécanique

Conference given outside the academic context (2010)

A brief summary of reserarches performed at the University of Liège in the frame of micromechanics. (slides)

Pure equilibrium tetrahedral finite elements for global error estimation by dual analysis

in International Journal for Numerical Methods in Engineering (2010)

This study presents a general porocedure of creating pure equilibrium tetrahedral finite elements. These elements are of the Fraeijs de Veubeke type. The spurious kinematical modes which inevitably appear ... [more ▼]

This study presents a general porocedure of creating pure equilibrium tetrahedral finite elements. These elements are of the Fraeijs de Veubeke type. The spurious kinematical modes which inevitably appear in this approach are eliminated by converting each tetrahedron in a super-element consisting of four tetrahedral primitive elements. A mathematical discussion on the number of spurious kinematical modes is presented. The development of first and second degree elements is presented in detail, and their efficiency in the frame of global errror estimation by dual analysis is emphasized by two numerical applications. The main attribute of the error estimation by dual analysis is that it provides an upper bound of the discretization error. [less ▲]

La fonction guidage en micromécanique

Book published by DEBONGNIE (JEAN-FRANCOIS) (2010)

1) Modelling the stiffness of a circular notch hinge subjected to flexure, torsion or shear : asymptotic values for a vanishing thickness and correction factors for the general case. 2) Flexible membrane ... [more ▼]

1) Modelling the stiffness of a circular notch hinge subjected to flexure, torsion or shear : asymptotic values for a vanishing thickness and correction factors for the general case. 2) Flexible membrane : stiffness for vanishing radius ratio and correction factor for the general case. 3) Conclusion. 4) Appendices, including a summary of useful formulae. [less ▲]

Sur la consistance du lissage des contraintes par convolution

in Agouzoul, Mohammed (Ed.) Actes du neuvième congrès de mécanique (2009, April)

This paper is devoted to the analysis of a stress-smoothing procedure by convolution. The key result is that any convolution kernel does not generally lead to accurate results, it is to say, a consistency ... [more ▼]

This paper is devoted to the analysis of a stress-smoothing procedure by convolution. The key result is that any convolution kernel does not generally lead to accurate results, it is to say, a consistency condition has to be verified. Consistent kernels are then developed. [less ▲]

LECONS D'ANALYSE NUMERIQUE - DEUXIEME PARTIE

Book published by DEBONGNIE (JEAN-FRANCOIS) (2009)

Version étoffée d'un cours donné par l'auteur à l'EMI, Rabat, de 1979 à 1985

Simulation of machining processes at global scale using SAMCEF for machining

(2008, November)

SAMCEF for Machining is a professional solution dedicated to process engineers. This Computer Aided Engineering tool focuses on the simulation of the machined part behavior at a global scale. Several ... [more ▼]

SAMCEF for Machining is a professional solution dedicated to process engineers. This Computer Aided Engineering tool focuses on the simulation of the machined part behavior at a global scale. Several aspects of machining are taken into account such as form errors, chatter or thermal aspects. In this paper, we present a few industrial applications that demonstrate the benefits of simulation in production planning : reduction of setup delays, limitation of experimental validations, cost reduction. [less ▲]