Auswahl der wissenschaftlichen Literatur zum Thema „Couche de lubrification“
Geben Sie eine Quelle nach APA, MLA, Chicago, Harvard und anderen Zitierweisen an
Inhaltsverzeichnis
Machen Sie sich mit den Listen der aktuellen Artikel, Bücher, Dissertationen, Berichten und anderer wissenschaftlichen Quellen zum Thema "Couche de lubrification" bekannt.
Neben jedem Werk im Literaturverzeichnis ist die Option "Zur Bibliographie hinzufügen" verfügbar. Nutzen Sie sie, wird Ihre bibliographische Angabe des gewählten Werkes nach der nötigen Zitierweise (APA, MLA, Harvard, Chicago, Vancouver usw.) automatisch gestaltet.
Sie können auch den vollen Text der wissenschaftlichen Publikation im PDF-Format herunterladen und eine Online-Annotation der Arbeit lesen, wenn die relevanten Parameter in den Metadaten verfügbar sind.
Dissertationen zum Thema "Couche de lubrification"
Trifa, Mohamed. „Nanorhéologie du contact sphère-plan avec couche mince interfaciale“. Ecully, Ecole centrale de Lyon, 1999. http://bibli.ec-lyon.fr/exl-doc/TH_T1780_mtrifa.pdf.
Der volle Inhalt der QuelleThe surface force apparatus developed at E. C. L. By A. Tonck and J. M. Georges is frequently used in the characterisation of confined fluid (such as lubrification oil or polymer solution). The exploration of such experimental results requires a precise analysis of the contact problem between an elastic place and an elastic sphere separated by a thin interfacial layer which may be considered eleastic, viscous or viscoelastic. Previous works in this direction (F. Auslender) leads to a generalised Reynolds equation describing, under imposed harmonic vertical displacement, the sphere plane contact with an heterogeneous viscoelastic compressible interfacial layer. In this work we intend to account, in the context of the previous analysis, the deformation of the elastic substrate. In order to clarify the roles of the film compressibility and the substrate deflection, we have studied two simple configurations : the first one is the case of an homogeneous elastic solid as interfacial layer, the second one is the case of a compressible Newtonian viscous fluid as interfacial layer. By reffering to experimental results, we have identified the rheological characteristics for three types of lubricant oils. The interface heterogeneity has been represented by two parietal solid layers with the same characteristics, separated by a fluid bulk. In order to obtain more information on the parietal layers rheology, we have studied their contact, assuming them to obey to hyperelastic behaviour laws associated to compressible Mooney - Rivlin elastic energy
Damiens, Bruno. „Modélisation de la lubrification sous-alimentée dans les contacts élastohydrodynamiques elliptiques“. Lyon, INSA, 2003. http://theses.insa-lyon.fr/publication/2003ISAL0037/these.pdf.
Der volle Inhalt der QuelleThe life of lubricated mechanisms is a function of the lubricant film thickness separating the contacting solids. The degree of lubricant starvation affects this film thickness and the life of the mechanisms. A free boundary model has been adopted. The lubricant distribution in the inlet of the contact is used as a boundary condition. The "multigrid" and "Multi-Level Multi-Integral" techniques, used to solve the equations describing the problem, are briefly exposed. The pressure field and the deformed geometry of the surfaces are obtained on the computational domain. This solution allows the validation of an analytical model developed to study the ejection flow and to quantify this flow in the boundary layer surrounding the contact. The flow is governed by the width of the boundary layer. This width, determines the contact response to a lubricant starvation. The dimensionless width can also be used to predict the persistence of local lubricant starvation, in a particular mechanism
Damiens, Bruno Lubrecht Antonius A. „Modélisation de la lubrification sous-alimentée dans les contacts élastohydrodynamiques elliptiques“. Villeurbanne : Doc'INSA, 2004. http://docinsa.insa-lyon.fr/these/pont.php?id=damiens.
Der volle Inhalt der QuelleRmili, Yosra. „ÉTUDE DE LA DILATANCE DE REYNOLDS DU BÉTON ET DE SON EFFET SUR LA FORMATION DE LA COUCHE DE LUBRIFICATION DANS LES TUYAUX DE POMPAGE“. Electronic Thesis or Diss., CY Cergy Paris Université, 2024. http://www.theses.fr/2024CYUN1283.
Der volle Inhalt der QuelleConcrete pumping process is important in the construction sector, facilitating the transport of fresh concrete to the casting site, even in difficult-to-access areas. This technique enables the achievement of considerable heights and distances. However, this process presents challenges. Therefore, accurately predicting the pumpability of concrete appears to be essential. Indeed, concrete pumpability relies on its rheological properties and its ability to form a lubrication layer (LL) during its flow through pipes. Accordingly, it is worthy to mention that mastering the rheology of concrete and understanding the characteristics of the LL is important, especially considering that the mechanisms of LL formation remain not well understood.This project focuses on investigating Reynolds dilatancy (RD), a potential mechanism involved in LL formation, and aims to highlight the key parameters governing it. The first part of the study introduces the development of a new method to assess shear-induced variations (RD) at free-surface flow. This method, although more reliable for conventional vibrated concrete (CVC), it does not fully explore this mechanism. Consequently, a new empirical device, the CRD-Test, was designed to evaluate the RD of self-compacting concrete (SCC) subjected to various scenarios under free-surface and pressurized conditions, simulating real casting and pumping processes. In this second part of the study, SCC is considered as a biphasic mixture of coarser particles (> 1.25 mm) in a fluid matrix of fine mortar (< 1.25 mm). Moreover, the new experimental device, named CRD-Test, offers wide range of shear and pressure levels. It is based on a modified coaxial cylinder tribometer, with a rotational speed ranging from 0 to 3 rps, and an air pressure regulator from 0 to 300 kPa. The RD phenomenon is manifested by fluctuations in lateral pressure measured at the outer cylinder of this apparatus and it was investigated through new indices.Experimental results reveal that RD values were found to be in good agreement with the workability and design parameters of the investigated concrete mixtures. Concrete with low fluidity values exhibited high RD indices under both free-surface and pressurized shear conditions. Furthermore, a biphasic approach highlights correlations between RD and the characteristics of aggregates with a diameter greater than 1.25 mm, as well as the viscoplastic characteristics of the fine mortar (i.e., the suspending phase). Moreover, RD results are mainly affected by the relative packing density of coarse aggregate during pumping process. Finally, Reynold values were in good agreement with flow regime characteristics, particle dynamics, and shear-induced particle migration indices. According to established correlations, dynamic segregation can significantly influence the mechanisms of LL formation during concrete pumping at low shear rates, illustrating the importance of Reynolds dilatancy in this process. However, at higher shear rates, dynamic segregation has been observed to negatively impact RD values, thereby increasing the risk of blockage during concrete pumping
Maupas-Zarrad, Hanène. „Lubrification des micromécanismes“. Ecully, Ecole centrale de Lyon, 1995. http://www.theses.fr/1995ECDLA020.
Der volle Inhalt der QuelleThe silicon-made and nickel-made micromecanisms realized until now have all the major disadvantage to wear very fast. In order to lubricate such micromecanisms, the idea is to graft on the rubbing surfaces organic monolayers, that have a few nanometers of thickness. The objective of the study is the development and the optimization of this technique of lubrification
De, Feo Modestino. „Impact du vieillissement de l'additif MoDTC sur ses propriétés tribologiques pour les contacts acier-acier et DLC-acier“. Thesis, Ecully, Ecole centrale de Lyon, 2015. http://www.theses.fr/2015ECDL0054/document.
Der volle Inhalt der QuelleEuropean legislation on vehicle emissions continues to become more severe to minimize the impact of Internal Combustion Engines (ICE) on the environment. One area of significant concern in this respect is the reduction of friction losses resulting in reduced emissions and as well as higher fuel efficiency and lower fuel consumption. To decrease these losses, several approaches have been made particularly at design of mechanical parts stage and at experimental level to optimize lubricant components. A great contribution to solve the problem can be given by the optimization of the additives package blended into the engine lubricants. The molybdenum dithiocarbamate (MoDTC) is the additive showing the best tribological performance by acting as friction modifier. It decomposes under high temperatures and pressure, forming layered structures on the engine surfaces. However, the use of effective friction reducing additives to achieve low boundary friction coefficient is not enough to have great engine fuel efficiency. In addition, in fact, it is needed also to maximize their durability, preventing premature consumption or depletion of these additives. It has been shown, in fact, that the friction reduction performance of MoDTC is sensitive to engine operating time and that is related to the degradation of MoDTC itself. In the first part of my thesis we tried to get a good comprehension of the chemical mechanisms of MoDTC ageing and to study the impact on the tribological properties. The chemical bulk oil characterization of MoDTC blended into the base oil when subjected to thermo-oxidative degradation allowed to propose a new hypothetical chemical pathway followed by the friction modifier molecules during the ageing process. At the same time, these findings were linked to the impact of the MoDTC degradation on its tribological properties. As reported in literature, another MoDTC drawback is its strong antagonism with DLC coating. In fact, when DLC-involving contacts are lubricated by MoDTC-containing base oil, a catastrophic DLC wear is produced. For this reason, in the second part of the project a multi-techniques approach has been adopted to get a better understanding of this wear mechanism. The combination of all the findings allowed to propose for the first time a new wear mechanism based on the formation of molybdenum carbide species inside the contact. A strong chemical interaction between the molybdenum-based species formed on the steel counter-body and the carbon of the DLC material has been supposed, leading to the formation of MoC species. All the results found are discussed to clarify the correlation between degradation time, tribological performance and tribofilm characterizations in both steel/steel and DLC/steel contact
Auslender, François. „Nanorhéologie des couches minces confinées application aux appareils à forces de surface“. Ecully, Ecole centrale de Lyon, 1996. http://www.theses.fr/1996ECDL0042.
Der volle Inhalt der QuelleDoki-Thonon, Thomas. „Thermal effects in elastohydrodynamic spinning circular contacts“. Phd thesis, INSA de Lyon, 2012. http://tel.archives-ouvertes.fr/tel-00749882.
Der volle Inhalt der QuelleMatta, Christine Martin Jean-Michel. „Lubrification des couches minces de carbone adamantin non hydrogéné Supraglissement avec les alcools /“. [S.l.] : [s.n.], 2009. http://bibli.ec-lyon.fr/exl-doc/cmatta.pdf.
Der volle Inhalt der QuelleSoullier, Jérémie. „Monocouches auto-assemblées d'acides phosphoniques comme revêtements lubrifiants“. Montpellier 2, 2007. http://www.theses.fr/2007MON20125.
Der volle Inhalt der Quelle