Génie mécanique
Contribution to Inverse Kinematic Modeling of a Planar Continuum Robot Using a Particle Swarm Optimization
According to the literature, research on modeling continuum robots isfocused on ways to develop the kinematic models, because of the lack of analyticalmodels for these robots and the complexity of the problem which reside in thecoupling of operational variables and infinite of possible solutions for a desiredconfiguration. This paper presents a numerical approach for solving the inversekinematic model of a planar continuum robot (PCR), assuming that each sectionof the manipulator is curved as a circular arc, with an inextensible central axis ofthe structure. At first, this paper presents an inverse kinematic model solution forone bending section, whereas the extreme points, of each section, used in calculatingthe inverse kinematic model for multi-sections is calculated numerically usinga particle swarm optimization (PSO) technique. Finally, Simulation examples ofthis method are carried to validate the proposed approach. Voir les détails
Mots clés : Planar continuum robot, modeling, Inverse kinematic model, optimization, Particle Swarm Optimization
An Effective Method for Bearing Faults diagnosis
The bearings are the most important mechanicalelements of rotating machinery. They are employed to supportand rotate the shafts in rotating machinery. An unexpected defectof the bearing may cause significant economic losses. For thatreason, the condition monitoring of these bearings has become afundamental axis of development and industrial research. Thefocus of this paper is to combine tow conventional methods:Hilbert Transform (HT) and Discrete Wavelet Transform (DWT)to develop a better method for detection and diagnosis the bearingfaults .This new method applied on real measurement signalscollected from an experimental vibration system. The monitoringresults indicate that the proposed method improves the bearingfaults diagnosis compared to other common techniques. Voir les détails
Mots clés : Vibration analysis, bearing Fault diagnosis, Hilbert Transform (HT), Envelope Analysis (EA), Discrete Wavelet Transform (DWT) ), Fast Fourier Transform (FFT)
Effects of a circular defect size and position on the damage progression in hybrid laminates under compressive loading.
The effects of a circular defect size and position on the post-damage response of the FMLs laminates under compressive loading have been studied. Compression tests are performed on composite plates comprising a hole having different diameters (8mm, 12mm and 16mm) and located at different positions (25%, 50% and 75%) in the loading direction. A numerical analysis using the finite element method FEM has permits the identification of the initiation zones and the description of the damage evolution in these laminates. The results of the numerical simulation are in good agreement with the experimental results. The FEM has well predicted the critical damage zones. Voir les détails
Mots clés : Defect, damage, hybrid laminate, FEM
Influence des paramètres de traitement par brunissage sur la texture de la surface
Résumé : Le procédé de brunissage (galetage à la bille) est l’un des moyens de finition et d’amélioration de la texture de surface d’une pièce mécanique. La texture de la surface est matérialisée par la rugosité et l’orientation de la direction prédominante des stries en travers de la surface. Cette orientation est d’une grande importance dans un contact mécanique, elle peut être évaluée par le rapport d’aspect de texture " Str" appelé indicateur d’isotropie de la surface. Ce travail a pour objectif de mettre en relief, l’influence des paramètres de traitement par brunissage sur l’orientation des stries. Les paramètres considérés sont : l'effort appliqué " Py ", l'avance " f " et le diamètre de bille " Db ". Au moyen d’un modèle mathématique basé sur les plans factoriels de Box-behenken, un régime optimal offrant le meilleur rapport de texture " Str ", a été déterminé. Voir les détails
Mots clés : Modèle mathématique., paramètres de brunissage, paramètre de texture
Étude expérimentale du délaminageen mode I des tubes fabriquéspar enroulement filamentaire
The good behavior of composite materials under mechanical loading, make it aserious competitor to traditional materials. Inter laminar defects induced duringimplementation or during stress are the main sources of its interlaminar progressive damagecausing separation of the layers known as the delamination. This work is an experimentalstudy of mode I delamination of a laminated composite [±θ°] manufactured as a tube by thefilament winding process. Technical delamination characterization by DCB test specimens(Double Cantilever Beam) are used to determine the energy release rate in mode I andevolution of delamination resistance curves R. Tests were performed according to ASTMD5528 standard and the energy release rate in mode I (GIC) of two configurations isdetermined by the method of Berry. Voir les détails
Mots clés : matériaux composites, enroulement filamentaire, endommagement, délaminage, mode I, taux de restitution d’énergie, courbes-R
MicroFluidic Oscillator: A Technical Solutionfor MicroMixture
The diffusion flux given by the Fick’s law characterizethe mixing rate. A passive mixingstrategy is proposed to enhance mixing of two fluids through perturbed jet low. A numerical studyof passive mixers has been presented. This paper is focused on the modeling of a micro-injectionsystems composed of passive amplifier without mechanical part. The micro-system modeling isbased on geometrical oscillators form. An asymmetric micro-oscillator design based on amonostable fluidic amplifier is proposed [2,7]. The characteristic size of the channels is generallyabout a few hundred of microns. The numerical results indicate that the mixing performance can beas high as 99 % within a typical mixing chamber of0.20 mm diameter inlet and 2.0 mm distance ofnozzle - spliter. In addition, the results confirm that self-rotation in the circular mixer significantlyenhances the mixing performance. The novel micro mixing method presented in this study providesa simple solution to mixing problems in microsystem. Voir les détails
Mots clés : Micro oscillator, modeling, Micro mixture, diffusion, Size effect.
Numerical Simulation of Droplet Breakup, Splitting andSorting in a Microfluidic Device
Droplet generation, splitting and sorting are investigated numericallyin the framework of a VOF technique for interface tracking and a finite-volumenumerical method using the commercial code FLUENT. Droplets of water-in-oilare produced by a flow focusing technique relying on the use of a microchannellequipped with an obstacle to split the droplets. The influence of several parameterspotentially affecting this process is investigated parametrically towards the endof identifying "optimal" conditions for droplet breakup. Such parameters includesurface tension, the capillary number and the main channel width. We show thatthe capillary number plays a crucial role in determining droplet properties and theefficiency of the related generation process. An obstacle configuration can be effectivelyused to split a droplet, with the droplets being naturally sorted at the endof the main channel. Larger values of the capillary number generally lead to anincrease in the droplet frequency and a decrease in its typical size. Voir les détails
Mots clés : Water droplet, flow focusing, splitting, sorting, CFD, VOF, microchannel
Microdrops in Microfluidic: Estimation of Geometrical Form
Manipulation of small-sized liquid quantities is one of the key issues in technology, biology, chemistry and medicine.Where the increased surface-to-volume ratio making surface effects more dominant [42], which allows toreduce time of reaction and economies the costs of manufacturing products. The microdrop is a typical example of asmall-sized liquid quantity; that can be considered as samples, reagents and supplementary indicator to approach us inthe direction of reaction and the state of microdrop. The creation of reproducible in stable geometrical form ofmicrodrop makes a critical step during the manufacturing of microdrop. Pressure based manufacturing of microdropnowadays a common way to create reproducible and stable small-sized drops. Many geometrical form of microdropcan be generated in different techniques. Proofed that microdevices based on pressure based manufacturing ofmicrodrops has already been successfully implemented. This paper serves as a review of the most importantcontributions, in the development of the creation of reproducible and stable microdrops in the past decades. Besidesserving as a reverence for researchers in this area, this paper is also a resource for everybody who wants to identify theeasiest way to precise microdrops geometrical form for a particular application by simple analysis. Voir les détails
Mots clés : form, microdrop, description and theoretical analysis.
Soudage hétérogène de deux aciers à hautes limites élastiques HSLA(X70) : Étude du comportement mécanique
L’assemblage des matériaux par soudure hétérogène occupe une place importante dans l’univers de l’industrie. Bien précisément les aciers inoxydables sont plus utilisables vu leur bonne soudabilité par tous les procèdesde soudage à l’arc. L’objectif de cette étude est la caractérisation microstructurale et mécanique d’une soudure hétérogène de deux couples d’aciers (HSLA). Les résultats obtenus montrent que la zone fondue de l’électrode austénitique subit un durcissement avec une résistance au choc élavé par rapport à la zone de l’électrode faiblement allié, ainsi, on a constaté que l'acier qui contient le tanneur bas de carbone possède le meilleur comportement mécanique. Voir les détails
Mots clés : HLE, SMAW, 308L, Soudure hétérogène.
Etude et dimensionnement d’un système solaire combiné Application: Logement individuel type F3 à Batna
Un système solaire combiné est une installation solaire qui fournit à la fois de l’eau chaude sanitaire et le chauffage. L’objet de ce travail est le dimensionnement d’un système solaire combiné (détermination de la surface de captation du système). Deux parties essentielles sont traitées : la première partie est consacrée au calcul des apports solaires pour le site de Batna et la seconde partie pour les calculs des besoins mensuelles de chauffage et en eau chaude sanitaire dans le cas d’une famille de cinq personnes à la ville de Batna. La demande mensuelle du chauffage est d'environ 1600 kWh en hiver, pour une température désirée égale à 20 °C et une température extérieure d’environ 6 °C. La demande en eau chaude sanitaire d’une famille de cinq personnes est de 400 kWh/mois. Voir les détails
Mots clés : Système solaire combiné, Chauffage solaire, Eau chaude sanitaire.