{"title":"Étude par la méthode d’homogénéisation des effets combinés de la rugosité de surface et de la rhéologie du lubrifiant sur le comportement d’un contact hydrodynamique","authors":"Ahcen Mouassa, M. Lahmar, B. Bou-Saïd","doi":"10.1051/MECA/2010044","DOIUrl":"https://doi.org/10.1051/MECA/2010044","url":null,"abstract":"Dans cet article, les effets combines de la rugosite de surface et de la rheologie du lubrifiant additive sur les performances hydrodynamiques d’un patin plan incline sont etudies au moyen de la methode d’homogeneisation. La surface du patin contigue au film est supposee fixe et rugueuse tandis que la surface inferieure mobile est parfaitement lisse. Le modele de fluide polaire ou a couple de contrainte de V.K. Stokes est adopte pour decrire le comportement rheologique du lubrifiant s’ecoulant entre les deux surfaces. Les etudes de simulation sont effectuees en considerant trois formes de rugosites (transversales, longitudinales et anisotropes) et differentes valeurs du parametre de couple de contrainte. La comparaison des solutions obtenues par les methodes deterministe et d’homogeneisation a permis de conclure que la methode d’homogeneisation est efficace pour les trois formes de rugosite envisagees. Les resultats de l’etude parametrique effectuee montrent que les rugosites de surface et les couples de contraintes dus a la presence des additifs polymeriques dans le lubrifiant ont des effets non negligeables sur les performances hydrodynamiques du contact, a savoir : le champ de pression, la capacite de charge, le nombre de frottement et la puissance dissipee.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"5 1","pages":"345-363"},"PeriodicalIF":0.0,"publicationDate":"2010-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88922324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Collet, Morvan Ouisse, E. Foltête, C. Lexcellent
{"title":"Sur la réponse transitoire d'une structure en alliage à mémoire de forme soumise à un impact","authors":"M. Collet, Morvan Ouisse, E. Foltête, C. Lexcellent","doi":"10.1051/MECA/2010054","DOIUrl":"https://doi.org/10.1051/MECA/2010054","url":null,"abstract":"Dans cet article sont presentees des evolutions du modele RL necessaires pour la resolution de problemes de dynamique rapide. Le modele initial, base sur le comportement thermomecanique de l’alliage couple a l’equation de la chaleur, a ete implemente dans le cadre de la dynamique basses frequences dans des travaux anterieurs. L’utilisation de ce modele non-lineaire dans le cadre de la dynamique rapide (reponse de la structure a un impact) conduit a des solutions non physiques ou a des divergences des algorithmes d’integration temporelle. Ces comportements sont principalement dus aux fortes non-linearites des equations regissant les cinetiques de transformation entre les deux phases du materiau (austenite/martensite). L’adjonction d’un terme lissant dans les equations differentielles permet de faire converger les algorithmes sans perturber le comportement du modele initial. Ce terme, d’un point de vue physique, traduit le fait que la transformation de phase ne se fait pas de facon instantanee, mais a une vitesse de propagation donnee. Les resultats issus d’un calcul elements-finis considerant une structure bidimensionnelle soumise a un impact sont presentes.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"77 1","pages":"407-417"},"PeriodicalIF":0.0,"publicationDate":"2010-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72614337","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A numerical simulation of viscous shear effects on porous squeeze-film using the Darcy-Brinkman model","authors":"M. Nabhani, M. Khlifi, B. Bou-Saïd","doi":"10.1051/MECA/2010046","DOIUrl":"https://doi.org/10.1051/MECA/2010046","url":null,"abstract":"In recent decades, problems related to the squeeze of fluid films in the presence of a porous medium draw attention of researchers and are the subject of many applied studies for industry and biomechanics. Our concerns in this paper are the numerical simulation of the viscous shear stresses effects on the fluid film characteristics between two discs with one porous. This study is based on the coupling, at the fluid film-porous disc interface, of the Darcy-Brinkman equations in the porous medium and the modified Reynolds equation describing the flow in the fluid film. The system of equations obtained is discretized by the means of finite differences method and solved numerically using the technique of Successive Over-Relaxation (SOR). The results show that the viscous shear effects increase the radial and the axial fluid film velocities as well as the squeeze film velocity but decrease the response time. Moreover, these effects are enlarged for smaller viscous shear parameter and for smaller fluid film thickness.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"48 1","pages":"327-337"},"PeriodicalIF":0.0,"publicationDate":"2010-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73577336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Modal control using real-time identification for time-varying structures","authors":"Fengyan Deng, D. Rémond, L. Gaudiller","doi":"10.1051/MECA/2010055","DOIUrl":"https://doi.org/10.1051/MECA/2010055","url":null,"abstract":"For a controlled structure, the changes of physical characteristics like natural frequencies, modal damping coefficients, and what's more on mode shapes will destabilize the controlled system. To keep the control performance and guarantee its robustness, a new modal control method using real-time identification is proposed to overcome the instability of controlled structure, especially induced by the inversion of mode shape. In this paper, a modal model of time-varying mechanical structure is supplied by an identifier. The choice of the kind of control permits to use this time-varying model for optimizing and self-adapting the controller. In order to supply the controller, a modal observer is used and also updated. For illustrative purpose, this proposed methodology is carried out on a simple but representative time-varying mechanical structure. On this example, an inertia modification leads not only to low modal frequency shifts but also to inversion of a mode shape. This mode shape inversion is shown to destabilize the controlled structure when the control system is not updated. The overall procedure will be described through simulations and performed for different operating conditions, which will prove that mode shapes have to be precisely determined and updated in the controller and observer to guarantee a robust modal control with high performances in spite of the changes of structure.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"9 1","pages":"513-520"},"PeriodicalIF":0.0,"publicationDate":"2010-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84236157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Frédéric Druesne, B. Lefèvre, J. Dulong, P. Villon
{"title":"Simulation d’un problème de contact par des méthodes de réduction de modèle pour une application temps réel","authors":"Frédéric Druesne, B. Lefèvre, J. Dulong, P. Villon","doi":"10.1051/MECA/2010037","DOIUrl":"https://doi.org/10.1051/MECA/2010037","url":null,"abstract":"Les outils de CAO et de realite virtuelle sont utiles pour simuler en temps reel la manipulation de pieces rigides, avec une detection des collisions. Les simulateurs temps reel industriels ont egalement besoin de prendre en compte les pieces deformables; cela suppose de pouvoir calculer en temps reel la deformee de pieces en contact. La methode des elements-finis ne peut pas fournir la deformee en temps reel pour un modele a non-linearites geometrique, materielle et de contact. Une methodologie composee de deux phases est ici proposee. Tout d’abord, une phase d’apprentissage consiste a realiser une campagne de precalculs par elements-finis representative des besoins de la simulation en temps reel. Puis, la phase temps reel, non exposee dans cet article, exploite par interpolation la surface de reponse obtenue lors de cette campagne de precalculs. L’objectif de cet article, dans le cadre de la phase d’apprentissage, est de construire une surface de reponse reduite; pour cela des methodes de reduction de modele sont utilisees. Trois niveaux de reduction sont etudies : une methode adaptative avec base, la technique POD, et l’hyper reduction. L’ecrasement d’un cylindre en caoutchouc sera etudie afin d’evaluer la performance de ces differentes methodes.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"22 1","pages":"255-264"},"PeriodicalIF":0.0,"publicationDate":"2010-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78951382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Conception automatique et optimisation des surfaces additionnelles pour le procédé d’emboutissage","authors":"K. Debray, Ming Dong, Y. Guo","doi":"10.1051/MECA/2010035","DOIUrl":"https://doi.org/10.1051/MECA/2010035","url":null,"abstract":"In the forming process of a thin sheet part such as the automobile bodies or the components of electric household appliances, some surfaces should be added to the desired part in order to hold the part and to avoid the defects such as the rupture, wrinkling and surface scratching. These addendum surfaces are mainly composed of protection walls and blank holder surfaces. The main aim of this study is to propose a methodology and the corresponding numerical tools for the automatic design and optimization of the addendum surfaces in the sheet forming process. The automatic design of addendum surfaces is based on the creation of the curves of profile and surfaces of COONS. These surfaces are then meshed automatically and the simulation of the stamping problem is solved with the Inverse Approach. Finally, the geometrical parameters necessary for the creation of surfaces are optimized in order to satisfy the mechanical criteria for the process of stamping. These parametric tools of design-simulation-optimization make it possible to quickly lead to optimal addendum surfaces.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"115 1","pages":"215-221"},"PeriodicalIF":0.0,"publicationDate":"2010-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79577450","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Simulation du comportement mécanique des alliages de titane pour les procédés de mise en forme à froid de produits plats","authors":"Benoit Revil-Baudard, E. Massoni","doi":"10.1051/MECA/2010029","DOIUrl":"https://doi.org/10.1051/MECA/2010029","url":null,"abstract":"In this paper, the mechanical behaviour of α titanium alloys is modelised for the cold forming processes. The elasto-plastic constitutive law is decomposed in an anisotropic plastic criterion, an isotropic hardening and a kinematic hardening. Non quadratic criteria have been developed by Cazacu et al. (Orthotropic yield criterion for hexagonal closed packed metals, Int. J. Plasticity 22 (2006) 1171-1194), to model the plasticity of hexagonal closed packed materials. The implementation of this model in a finite element software switches between two bases, the equilibrium is calculated in a reference basis and the anisotropy axes define a local basis, updated by the deformation gradient. An identification procedure, based on tensile tests, allows to define all the parameters needed to model the elasto-plastic behaviour. Simulation of cold forming processes (bulging and deep drawing) have been done to validate this model. Numerical results are compared with experimental data, obtained from speckles analysis.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"31 1","pages":"265-270"},"PeriodicalIF":0.0,"publicationDate":"2010-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82958504","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Problèmes actuels en mécanique dans le domaine ferroviaire : vers l’omniprésence du non-linéaire et du stochastique","authors":"P.-E. Gautier","doi":"10.1051/MECA/2010060","DOIUrl":"https://doi.org/10.1051/MECA/2010060","url":null,"abstract":"Les problemes actuels en mecanique dans le domaine ferroviaire font intervenir de maniere\u0000 intensive des non-linearites, que ce soit dans le comportement des composants du systeme\u0000 (ex. ballast...), ou aux interfaces. Par ailleurs, la prise en compte de l’aleatoire dans\u0000 la modelisation devient incontournable, tant pour les sollicitations du systeme que pour\u0000 la variabilite de ses caracteristiques. Ces deux tendances sont illustrees sur des\u0000 exemples de problematiques actuelles : dynamique des vehicules et de l’infrastructure,\u0000 crissement...","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"7 1","pages":"167-175"},"PeriodicalIF":0.0,"publicationDate":"2010-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84294204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. Salles, L. Blanc, F. Thouverez, Alexander M. Gouskov, Pierrick Jean
{"title":"Analyse multi-échelle de l'usure par fretting sous chargement dynamique","authors":"L. Salles, L. Blanc, F. Thouverez, Alexander M. Gouskov, Pierrick Jean","doi":"10.1051/MECA/2010034","DOIUrl":"https://doi.org/10.1051/MECA/2010034","url":null,"abstract":"Dans cet article, nous abordons l'etude de la dynamique non-lineaire d'une roue aubagee couple au phenomene d'usure par fretting en pied d'aube. La methode d'analyse s'appuie sur une methode d'Equilibrage harmonique multi-echelle basee sur la separation en temps rapide et lent suivant les mecaniques mises en jeu. Un exemple numerique d'analyse vibratoire en fonction de l'usure d'une roue aubagee est presente.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"538 1","pages":"277-282"},"PeriodicalIF":0.0,"publicationDate":"2010-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73013914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Optimisation aéro-structurale de la voilure d’un avion d’affaires par un jeu de Nash et un partage adapté des variables","authors":"B. A. E. Majd, J. Désidéri, Abderrahmane Habbal","doi":"10.1051/MECA/2010041","DOIUrl":"https://doi.org/10.1051/MECA/2010041","url":null,"abstract":"This article focuses on multidisciplinary optimization in situations in which the different criteria that account for the various disciplines are functionals of distributed solutions of partial-differential equations. In the case of two disciplines, we propose a strategy in which the optimization process is carried out in two phases: (a) a cooperative-optimization phase throughout which both criteria improve at each iteration, and (b) an optional competitive-optimization phase by a Nash game associated with an adapted split of variables.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"3 1","pages":"209-214"},"PeriodicalIF":0.0,"publicationDate":"2010-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72932241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}