Jean Frêne - Academia.edu (original) (raw)
Papers by Jean Frêne
Rheological Theories · Measuring Techniques in Rheology Test Methods in Rheology · Fractures Rheological Properties of Materials · Rheo-Optics · Biorheology, 1975
Tribology Series, 2000
ABSTRACT We have studied the tribological behaviour of the paramagnetic Stainless steel/ferromagn... more ABSTRACT We have studied the tribological behaviour of the paramagnetic Stainless steel/ferromagnetic Nickel sliding couple in the presence and the absence of a D.C. magnetic field. Experiments were conducted on pin/disc tribometer in ambient atmosphere under applied normal load P=3.4 N and sliding speed v=0.67 m/s. The magnetic field was applied to the Nickel pin and remained constant during test. Experimental results showed that the presence of magnetic field around the tribocontact modifies its tribological behaviour by action on the mechanical properties of the subsurfaces contact. The suppression of Weiss domains in material by magnetisation induces an increase of the dislocations movements to the contact surface (1). This concentration of the surface dislocations increases the microhardness of the subsurfaces activates the surface oxidation of Nickel and steel and modifies the tribocontact rheology. The modification induced in contact surfaces and subsurfaces, by the magnetic field of H=4500 A/m after one hour of sliding, are analysed and performed by Vickers microhardness, Scanning Electron Microscopy and Energy Dispersive Spectroscopy EDS analysis. The microhardness gradient in pin is about 2 Hv/μm in a thin layer of 20 μm of the material and that of disc is about 3 Hv/μ in 20 μm of the material depth. The consumed oxygen by the magnetised sliding surfaces increases by a factor 15. The friction coefficient becomes more stable and decreases from μ=0.6 to 0.4. On the other side, the wear rate of pin disc increases. In this paper we will present a comparative tribological study of the contact with and without magnetic field.
Tribology Series, 2001
... Until a few years ago, each discipline was developing its own models: - very detailed ... bou... more ... Until a few years ago, each discipline was developing its own models: - very detailed ... boundary conditions: Feed pressure on both sides of the bearing (atmospheric pressure) and Giirnbel ... 3.New designs of squeeze film damper have been studied (active SFD with variable ...
Tribology International
ABSTRACT Times Cited: 0
Résumé Le comportement tribologique d'un couple Acier 48/Acier XC 48, glissant en présence du... more Résumé Le comportement tribologique d'un couple Acier 48/Acier XC 48, glissant en présence du champ magnétique créé par un courant électrique alternatif, a été analysé. Les tests ont été réalisés avec un tribomètre pion-disque à l'air ambiant (le champ magnétique est appliqué au pion). La concentration des dislocations près de la surface et l'oxydation du matériau favorisées par l'application du champ magnétique, modifie le frottement et l'usure du tribocontact. Les modifications induites en surface de contact et celles structurales en subsurface ont été analysées par la mesure de la microdureté, par un test de rayure, par Spectroscopie à Energie Dispersive (EDS) et par Microscopie Electronique à Balayage (MEB). Abstract Tribological behavior of XC 48 steel/XC 48 steel sliding couple in the presence of an A.C. magnetic field was analyzed. Experiments were conducted on a pin-on-disc tribometer in ambient atmosphere (magnetic field is applied to the pin). The conce...
Two methods for measuring velocity profiles in fluid films approximately one-millimeter thick are... more Two methods for measuring velocity profiles in fluid films approximately one-millimeter thick are presented. One method uses phosphorescent tracers and is suitable for steady state flow; the other method uses reflective particles and is suitable for both steady and unsteady flows. Results obtained for flow between two rotating eccentric cylinders confirm the accuracy of the methods.
The effect of the deformation of an automotive connecting-rod on the oil film characteristics are... more The effect of the deformation of an automotive connecting-rod on the oil film characteristics are studied. The simultaneous elastic deformation and pressure distribution are obtained by iterative methods in steady-state conditions under realistic speeds and loads (5500 rpm, 25,000 N). Plane elasticity relations are used in this study. The following parameters are investigated: bearing characteristics: bearing thickness B and bearing clearance C; operating conditions: journal speed N and applied load W; lubricant: viscosity mu //0 and piezoviscous coefficient alpha . As a result of the deformation, the maximum pressure and the attitude angle are decreased and the relative eccentricity is greatly increased. The minimum oil film thickness is slightly but systematically decreased. The piezoviscosity effect is noticeable only at high loads: it increases slightly the oil film thickness and the maximum pressure. Three pages of discussion of the paper are appended.
Le comportement tribologique du couple glissant magnétisé laiton/acier dépend fortement de l'... more Le comportement tribologique du couple glissant magnétisé laiton/acier dépend fortement de l'environnement gazeux autour du tribocontact, de la pression du gaz et de l'intensité du champ magnétique appliqué autour de la piste de contact. Les tests sont réalisés sous trois environnements à l'air libre, sous oxygène à 105 Pa et sous vide poussé à 5.10-4 Pa. Le plus grand coefficient de frottement est enregistré à l'air libre. En revanche, le taux d'usure le plus grand correspond à l'oxygène. Sous vide, le transfert des particules diminue le frottement et le taux d'usure. L'application du champ magnétique modifie les propriétés mécaniques des surfaces de contact du couple. Il modifie particulièrement la dureté des surfaces de contact. A l'air ambiant et sous oxygène, le champ magnétique diminue le coefficient de frottement du couple. Cependant, sous vide, l'influence du champ magnétique est insignifiante. Ceci est dû au manque d'oxygène dans ...
ARCHIVE Journal of Mechanical Engineering Science 1959-1982 (vols 1-23)
Thermal effects in hydrodynamic lubrication were recognized as very important since the first wor... more Thermal effects in hydrodynamic lubrication were recognized as very important since the first works in this field. This paper presents the evolution of research concerning thermal effects in hydrodynamic bearings from the first study published by Hirn in 1854. A summary of general thermoelastohydrodynamic theory for the journal bearing case and its comparison with experimental results is then presented.
Proceedings of the Institution of Mechanical Engineers Part D Journal of Automobile Engineering
Cet article présente l'analyse du comportement élastohydrodynamique d'un piston à jupe so... more Cet article présente l'analyse du comportement élastohydrodynamique d'un piston à jupe solide de moteur Diesel. Le mouvement secondaire, couplé avec l'effet de la lubrification du piston, est simulé en tenant de l'effet des charges thermomécaniques dues aux charges thermiques et à l'action de pression des gaz de combustion et à l'inertie du piston. Les résultats montrent la grande importance de l'effet des déformations thermiques sur l'EHD du piston.
Rheological Theories · Measuring Techniques in Rheology Test Methods in Rheology · Fractures Rheological Properties of Materials · Rheo-Optics · Biorheology, 1975
Tribology Series, 2000
ABSTRACT We have studied the tribological behaviour of the paramagnetic Stainless steel/ferromagn... more ABSTRACT We have studied the tribological behaviour of the paramagnetic Stainless steel/ferromagnetic Nickel sliding couple in the presence and the absence of a D.C. magnetic field. Experiments were conducted on pin/disc tribometer in ambient atmosphere under applied normal load P=3.4 N and sliding speed v=0.67 m/s. The magnetic field was applied to the Nickel pin and remained constant during test. Experimental results showed that the presence of magnetic field around the tribocontact modifies its tribological behaviour by action on the mechanical properties of the subsurfaces contact. The suppression of Weiss domains in material by magnetisation induces an increase of the dislocations movements to the contact surface (1). This concentration of the surface dislocations increases the microhardness of the subsurfaces activates the surface oxidation of Nickel and steel and modifies the tribocontact rheology. The modification induced in contact surfaces and subsurfaces, by the magnetic field of H=4500 A/m after one hour of sliding, are analysed and performed by Vickers microhardness, Scanning Electron Microscopy and Energy Dispersive Spectroscopy EDS analysis. The microhardness gradient in pin is about 2 Hv/μm in a thin layer of 20 μm of the material and that of disc is about 3 Hv/μ in 20 μm of the material depth. The consumed oxygen by the magnetised sliding surfaces increases by a factor 15. The friction coefficient becomes more stable and decreases from μ=0.6 to 0.4. On the other side, the wear rate of pin disc increases. In this paper we will present a comparative tribological study of the contact with and without magnetic field.
Tribology Series, 2001
... Until a few years ago, each discipline was developing its own models: - very detailed ... bou... more ... Until a few years ago, each discipline was developing its own models: - very detailed ... boundary conditions: Feed pressure on both sides of the bearing (atmospheric pressure) and Giirnbel ... 3.New designs of squeeze film damper have been studied (active SFD with variable ...
Tribology International
ABSTRACT Times Cited: 0
Résumé Le comportement tribologique d'un couple Acier 48/Acier XC 48, glissant en présence du... more Résumé Le comportement tribologique d'un couple Acier 48/Acier XC 48, glissant en présence du champ magnétique créé par un courant électrique alternatif, a été analysé. Les tests ont été réalisés avec un tribomètre pion-disque à l'air ambiant (le champ magnétique est appliqué au pion). La concentration des dislocations près de la surface et l'oxydation du matériau favorisées par l'application du champ magnétique, modifie le frottement et l'usure du tribocontact. Les modifications induites en surface de contact et celles structurales en subsurface ont été analysées par la mesure de la microdureté, par un test de rayure, par Spectroscopie à Energie Dispersive (EDS) et par Microscopie Electronique à Balayage (MEB). Abstract Tribological behavior of XC 48 steel/XC 48 steel sliding couple in the presence of an A.C. magnetic field was analyzed. Experiments were conducted on a pin-on-disc tribometer in ambient atmosphere (magnetic field is applied to the pin). The conce...
Two methods for measuring velocity profiles in fluid films approximately one-millimeter thick are... more Two methods for measuring velocity profiles in fluid films approximately one-millimeter thick are presented. One method uses phosphorescent tracers and is suitable for steady state flow; the other method uses reflective particles and is suitable for both steady and unsteady flows. Results obtained for flow between two rotating eccentric cylinders confirm the accuracy of the methods.
The effect of the deformation of an automotive connecting-rod on the oil film characteristics are... more The effect of the deformation of an automotive connecting-rod on the oil film characteristics are studied. The simultaneous elastic deformation and pressure distribution are obtained by iterative methods in steady-state conditions under realistic speeds and loads (5500 rpm, 25,000 N). Plane elasticity relations are used in this study. The following parameters are investigated: bearing characteristics: bearing thickness B and bearing clearance C; operating conditions: journal speed N and applied load W; lubricant: viscosity mu //0 and piezoviscous coefficient alpha . As a result of the deformation, the maximum pressure and the attitude angle are decreased and the relative eccentricity is greatly increased. The minimum oil film thickness is slightly but systematically decreased. The piezoviscosity effect is noticeable only at high loads: it increases slightly the oil film thickness and the maximum pressure. Three pages of discussion of the paper are appended.
Le comportement tribologique du couple glissant magnétisé laiton/acier dépend fortement de l'... more Le comportement tribologique du couple glissant magnétisé laiton/acier dépend fortement de l'environnement gazeux autour du tribocontact, de la pression du gaz et de l'intensité du champ magnétique appliqué autour de la piste de contact. Les tests sont réalisés sous trois environnements à l'air libre, sous oxygène à 105 Pa et sous vide poussé à 5.10-4 Pa. Le plus grand coefficient de frottement est enregistré à l'air libre. En revanche, le taux d'usure le plus grand correspond à l'oxygène. Sous vide, le transfert des particules diminue le frottement et le taux d'usure. L'application du champ magnétique modifie les propriétés mécaniques des surfaces de contact du couple. Il modifie particulièrement la dureté des surfaces de contact. A l'air ambiant et sous oxygène, le champ magnétique diminue le coefficient de frottement du couple. Cependant, sous vide, l'influence du champ magnétique est insignifiante. Ceci est dû au manque d'oxygène dans ...
ARCHIVE Journal of Mechanical Engineering Science 1959-1982 (vols 1-23)
Thermal effects in hydrodynamic lubrication were recognized as very important since the first wor... more Thermal effects in hydrodynamic lubrication were recognized as very important since the first works in this field. This paper presents the evolution of research concerning thermal effects in hydrodynamic bearings from the first study published by Hirn in 1854. A summary of general thermoelastohydrodynamic theory for the journal bearing case and its comparison with experimental results is then presented.
Proceedings of the Institution of Mechanical Engineers Part D Journal of Automobile Engineering
Cet article présente l'analyse du comportement élastohydrodynamique d'un piston à jupe so... more Cet article présente l'analyse du comportement élastohydrodynamique d'un piston à jupe solide de moteur Diesel. Le mouvement secondaire, couplé avec l'effet de la lubrification du piston, est simulé en tenant de l'effet des charges thermomécaniques dues aux charges thermiques et à l'action de pression des gaz de combustion et à l'inertie du piston. Les résultats montrent la grande importance de l'effet des déformations thermiques sur l'EHD du piston.