Mecanique & Industries最新文献

{"title":"Visualisation et mesures expérimentales dans un jet rond évoluant à nombre de Reynolds modéré","authors":"Yassine Zaouali, J. Jay, Habib Ben Aissia","doi":"10.1051/MECA/2010004","DOIUrl":"https://doi.org/10.1051/MECA/2010004","url":null,"abstract":"L’objectif de ce travail est d’etudier les instabilites de Kelvin-Helmholtz apparaissant dans un jet de fluide monophasique evoluant a nombres de Reynolds moderes. L’etude porte sur la region proche de la buse d’ejection (la zone de transition), et elle est localisee sur l’evolution dans l’espace et dans le temps des instabilites aerodynamiques specifiques a ce type d’ecoulement. Dans cette etude experimentale, les instabilites sont decrites qualitativement puis quantitativement a l’aide de la technique de tomographie par plan laser associee aux operateurs de traitement d’images. On s’interesse en particulier a l’etude des structures generees par l’instabilite des jets ainsi que la determination de leurs parametres caracteristiques.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"44 1","pages":"437-446"},"PeriodicalIF":0.0,"publicationDate":"2009-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90773570","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":"Study of the thermal behavior of a synchronous motor with permanent magnets","authors":"Souhil Seghir-Oualil, S. Harmand, D. Laloy, O. Phillipart","doi":"10.1051/MECA/2010006","DOIUrl":"https://doi.org/10.1051/MECA/2010006","url":null,"abstract":"The present study deals with the thermal behavior of an electric motor used in naval propulsion. A permanent three-dimensional model based on a nodal approach was developed to predict the thermal behavior of the machine in permanent state. The various heat transfer modes playing a role (mainly the conduction, the convection and the mass transfer) are taken into account. The three dimensional developed model provides information (in terms of heat fluxes or temperatures) for the whole machine. A parametric study using this model is carried out aiming at two objectives. The first one consists in an evaluation of the influence of several factors on the temperature distribution. The second one aims at obtaining the inception of the thermal optimization and evaluating the more efficient cooling techniques or solutions.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"14 1","pages":"455-476"},"PeriodicalIF":0.0,"publicationDate":"2009-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84751276","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":"Mechanical properties of an extruded wood plastic composite","authors":"F. Hugot, G. Cazaurang","doi":"10.1051/MECA/2010010","DOIUrl":"https://doi.org/10.1051/MECA/2010010","url":null,"abstract":"The focus of this study has been to fully describe the mechanical properties and behaviour of an extruded Wood Plastic Composite product. The use of plasturgy technologies for the elaboration of lignocellulose reinforced composites raises fundamental questions about the behaviour of these materials. Mechanical properties of a composite depend generally on fibre content, fibre/matrix interface link or added coupling agents. Processes play an important role on the reinforcement distribution in the matrix. The main purpose of this paper is to describe mechanical behaviour of WPC composites which are manufactured using an extrusion process. So, complete set of experiments has been realised: tensile, compressive, bending and shear tests. Longitudinal direction refers to extrusion process directional flow and transverse direction specimens have been tested. Mechanical performances of Wood Plastic Composites depend also on the link of fibre/matrix interface, fracture surface has been analysed using an optical microscope.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"20 1","pages":"519-524"},"PeriodicalIF":0.0,"publicationDate":"2009-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84280402","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":"Prise en compte des comportements viscoélastiques dans la simulation dynamique des systèmes de freinage","authors":"Sylvain Thouviot, G. Chevallier, F. Renaud, J. Dion, R. Lemaire","doi":"10.1051/MECA/2009072","DOIUrl":"https://doi.org/10.1051/MECA/2009072","url":null,"abstract":"Dans le cadre de la simulation des systemes de freinage, la mise en evidence de phenomenes tels que le crissement fait appel a des methodes specifiques. On s'interessera ici a l'analyse de stabilite par le calcul des pulsations et modes propres. L'utilisation de dispositifs amortissants \"shims\" pour la reduction du bruit de crissement implique que les simulations prennent en compte les effets amortissants des materiaux. On utilise pour cela des modeles de materiaux viscoelastiques et en particulier le modele de Maxwell generalise. Les travaux ont consiste a choisir et valider des outils (modeles viscoelastiques, formulations elements finis, ...) et a mettre en place une methode de simulation. Ils se sont divises en plusieurs etapes. Dans un premier temps, il a fallu selectionner, parmi plusieurs modeles mathematiques permettant de decrire la viscoelasticite, le plus adapte a la modelisation de l'amortissement dans les systemes de freinage. On a etudie les modeles a module complexe, de Kelvin-Voigt et de Maxwell generalise. Dans un second temps, il a fallu trouver une formulation du probleme elements finis adaptee a l'analyse modale. On a alors utilise une formulation en modele d'etat. Une hypothese importante concernant l'egalite des poles du modele de Maxwell a permis de limiter la taille du modele tout en simplifiant sa formulation. Enfin, les methodes mises en place ont ete appliquees a une plaquette de frein dans un premier temps et a un frein complet ensuite. Des analyses parametriques sur le nombre de modes de projection et l'ordre des modeles de Maxwell ont ete menees sur ces deux cas test. Dans le cas de la plaquette de frein, on a effectue une analyse modale complexe en prenant en compte la viscoelasticite du materiau de friction. L'objectif etait d'obtenir un recalage de la plaquette, en terme de frequences et d'amortissements, par rapport a une mesure FRF. Dans le cas du modele de frein complet, on a effectue une analyse modale complexe en prenant en compte la viscoelasticite des materiaux de friction et du \"shim\". Le modele de frein a egalement servi de support a la mise en evidence du lien entre la repartition de l'energie de deformation dans le frein et l'amortissement observe par analyse modale complexe. Pour conclure, on a developpe une methode de simulation utilisant Abaqus® , Matlab® pour la phase d'analyse modale complexe avec effets viscoelastiques et Python pour l'interfacage entre Abaqus® et Matlab® . Cette methode permet de traiter des problemes d'analyse de stabilite avec la prise en compte de plusieurs materiaux viscoelastiques, sur des modeles de grande dimension, sans surcout en terme de temps de calcul.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"24 1","pages":"385-396"},"PeriodicalIF":0.0,"publicationDate":"2009-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81238320","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":"Effect of manufacturing defects on the dynamic behaviour for an helical two-stage gear system","authors":"L. Walha, Yassine Driss, T. Fakhfakh, M. Haddar","doi":"10.1051/MECA/2009070","DOIUrl":"https://doi.org/10.1051/MECA/2009070","url":null,"abstract":"The modelling of the dynamic behaviour of three-dimensional model of two-stage gear system is formulated for general helical gears location. The excitation is induced by the periodic variation of the mesh stiffnesses. This case describes the real working of the gearings. First, the modal analysis of the system is treated. Then, the calculation of the dynamic response is performed by a step-by-step time integration method (Newmark method). Finally, two types of manufacturing defects on the gears are introduced in the model: eccentricity and profile defect. An analysis of the effects of these defects on the gear system dynamic behaviour is then treated.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"40 1","pages":"365-376"},"PeriodicalIF":0.0,"publicationDate":"2009-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89474126","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":"Piezoceramic shunted damping concept: testing, modelling and correlation","authors":"G. Chevallier, S. Ghorbel, A. Benjeddou","doi":"10.1051/MECA/2009073","DOIUrl":"https://doi.org/10.1051/MECA/2009073","url":null,"abstract":"New laboratory tests are presented for the experimental evaluation and assessment of the piezoceramic shunted damping (PSD) concept for cantilever Aluminium thin ( long ) beams bonded symmetrically on their upper/lower surfaces with single pairs of small piezoceramic patches. Following these tests outcome, the PSD efficiency measure is proposed to be the so-called modal effective electromechanical coupling coefficient , which is post-processed from free-vibrations analyses under short-circuit and open-circuit electrodes of the patches. For this purpose, the tests are numerically modelled, analysed, and correlated using ABAQUS ® commercial finite element (FE) code. Good tests/models correlations were reached after FE models electromechanical updating . This is attributed to the refined FE models in the sense that they have considered realistic and desirable features such as, electrodes equipotentiality , piezoceramic patches poling orientations (same/opposite), and the corresponding (parallel/series) electric wiring (connections).","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"46 1","pages":"397-411"},"PeriodicalIF":0.0,"publicationDate":"2009-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84142146","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":"Détermination de l'effort de contact pantographe-caténaire par méthode inverse","authors":"J. Berger, C. Clerc, Stéphane Teppe, Adrien Bobillot","doi":"10.1051/MECA/2009071","DOIUrl":"https://doi.org/10.1051/MECA/2009071","url":null,"abstract":"La connaissance de l'effort de contact entre le pantographe et la catenaire est un element essentiel de l'evaluation de la qualite du captage du courant. La SNCF etudie cet effort pour qualifier le materiel et les infrastructures nouvelles, ou en vue de detecter les defauts dans la catenaire. La methode de mesure utilisee jusqu'a present, basee sur une hypothese d'archet rigide, a une bande passante limitee bien en deca de la premiere frequence propre de l'archet. Pour franchir cette limitation, notamment pour les trains a grande vitesse, et pour la detection de defaut par analyse de la signature vibratoire, une nouvelle methodologie, basee sur la prise en compte des modes propres de l'archet, est proposee. Vibratec developpe depuis plusieurs annees des methodes inverses [6,7] pour remonter aux efforts injectes a partir des vibrations mesurees. L'originalite du contact pantographe catenaire reside dans le fait que la position du point de contact est une inconnue du probleme. La methode inverse utilisee est basee sur l'analyse modale des premiers modes de l'archet. L'ecriture de l'equilibre dynamique de l'archet permet d'aboutir a un systeme d'equations dont la resolution donne le module de l'effort et son point d'application. Les resultats obtenus sur un dispositif experimental de validation, a partir d'une base modale limitee aux 3 premiers modes de l'archet, montrent un gain important sur la bande utile de la mesure, qui passe de 45 Hz a 120 Hz. Par la suite, la bande passante pourra encore etre etendue en considerant davantage de modes de deformation de l'archet. Un utilitaire a ete developpe sous Matlab pour la mise en œuvre de la methode a partir de donnees experimentales.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"10 1","pages":"377-383"},"PeriodicalIF":0.0,"publicationDate":"2009-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90261065","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":"Interfacial stresses in externally FRP-plated structures: effect of shear deformations and fiber orientation","authors":"B. Kerboua, El Abbes, A. Bedia, Abdelouahad Tounsi","doi":"10.1051/MECA/2009067","DOIUrl":"https://doi.org/10.1051/MECA/2009067","url":null,"abstract":"The composite fiber materials of polymers (FRP) have physical properties, which are exploited recently for the reinforcement and rehabilitation of the structures, in mechanical, civil engineering and biomedical field, subjected to degradation or default risks. Since a beam without any form of reinforcement will fail when subjected to a relatively small tensile load. Therefore the use of the FRP to strengthen the structures is an effective solution to increase the overall strength technique. In this paper, a new theoretical approach model to estimate shear and peel-off stresses is proposed. Axial stresses and bending moment coupled with shear deformation and thermal effect in an FRP-strengthened beam are considered, including the variation in FRP plate fiber orientation.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"3 1","pages":"325-335"},"PeriodicalIF":0.0,"publicationDate":"2009-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82271057","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":"Modélisation plastique bi-linéaire de l'usure de matériaux abradables: application aux turbo-machines","authors":"M. Legrand, C. Pierre","doi":"10.1051/MECA/2010030","DOIUrl":"https://doi.org/10.1051/MECA/2010030","url":null,"abstract":"A simplified macroscopic implementation of abradable material wear in aircraft engines is introduced. These coatings are located along the circumference of the surrounding casings facing the blade-tips. More specifically, it is intended to numerically embed the abradable profile changes within an explicit time-stepping technique dedicated to blade-to-casing interactions by means of unilateral contact. This profile is updated through the use of a plastic constitutive law for the evolution of the abradable material. In order to keep low computational efforts allowing for parameter studies, a reduced order model of the blade of interest is built by following the Craig-Bampton modal synthesis technique. This choice is motivated because it offers the possibility to treat the contact constraints and wear conditions directly in the reduced-order space. It is shown that the mechanical behavior of the abradable material may initiate dangerous divergent motions of the blade. Under specific conditions, the use of abradable coatings should be avoided.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"51 1","pages":"283-288"},"PeriodicalIF":0.0,"publicationDate":"2009-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90343524","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":"Turbulence and waves in numerically simulated slope flows","authors":"E. Fedorovich, A. Shapiro","doi":"10.1051/MECA/2009046","DOIUrl":"https://doi.org/10.1051/MECA/2009046","url":null,"abstract":"Direct numerical simulation (DNS) is applied to investigate properties of katabatic and anabatic flows along thermally perturbed (in terms of surface buoyancy flux) sloping surfaces in the absence of rotation. Numerical experiments are conducted for homogeneous surface forcings over infinite planar slopes. The simulated flows are the turbulent analogs of the Prandtl (1942) one-dimensional laminar slope flow. The simulated flows achieve quasi-steady periodic regimes at large times, with turbulent fluctuations being modified by persistent low-frequency oscillatory motions with frequency equal to the product of the ambient buoyancy frequency and the sine of the slope angle. These oscillatory wave-type motions result from interactions between turbulence and ambient stable stratification despite the temporal constancy of the surface buoyant forcing. The structure of the mean-flow fields and turbulence statistics in simulated slope flows is analyzed. An integral dynamic similarity constraint for steady slope/wall flows forced by surface buoyancy flux is proposed and quantitatively verified against the DNS data.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"7 1","pages":"175-179"},"PeriodicalIF":0.0,"publicationDate":"2009-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85105306","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}