14. starptautiskā konference 2012 - Latvijas Jūras akadēmija

Proceedings of 14th International conference „Maritime Transport and Infrastructure - 2012”MECHANICS OF CONTACT INTERACTION OF PARTS IN FRICTIONCOMPONENT WITH REGARD TO THE RHEOLOGICAL PROPERTIESOF CONTACTAleksandrs Urbahs*, Gints Rijkuris ***Riga Technical University, 1 Kalku str., LV-1658, Latvia, aleksandrs.urbahs@rtu.lv**Latvian Maritime Academy, 5B Flotes str., LV-1016, Latvja, gints_rijkuris@inbox.lvAbstractMain problem described in this paper is that well-known theoretical approaches to calculate theactual contact area do not take into account the effect of time of loading and temperature of thecontacting surfaces of solids. In modern tribology [1, 2] wide range of phenomena caused byinteraction of the contacting surfaces of solids under normal load, offset, deformation of the materialsurface and the gas-liquid environment between the two contacting surfaces. Contact interaction infriction pairs largely determines their frictional characteristics, durability, and is therefore animportant object of tribology. By term of contact is understood the interaction of solid surfaces underthe influence of external forces considering their deviation from the ideal form, as well asparticipation in the deformation of the environment (gas and lubricants presence in the area ofcontact and indirect temperature). Main characteristics of the standard geometry of the roughsurfaces are also examined in this paper.IntroductionMacroscopic deviations from the ideal forms are lack of roundness, lack of flatness,corrugateness, etc. The scale these irregularities usually have is measured in the range of 10 -3 10 -4 m.Macroscopic asperity brings the microscopic irregularities which is measured at 10 -5 10 -7 scale. Inturn, microscopic asperities are measured in order of molecular dimensions.When determining the characteristics of the frictional interaction of rough surfaces and thearea of their contact altitudinal and longitudinal properties of the irregularities, the radius of curvatureof protrusions and depressions, the laws of their distribution and regulation are used.Another most significant aspect of the contacting of the surfaces is the molecular mechanics ofcontact. The surface energy of solids is so great that it causes the active interaction of the solid withcomponents of gases, liquids and parts of solids, forms adsorption and chemisorption layer on thesurfaces, adhesion force to resist motion, setting, deformation, heat and other processes.1. Geometry of rough surfaceIn a random arrangement of the asperities on the surfaces of contacting solids, actual area ofcontact which is known by the geometry of contacting surfaces limits bringing closer these contactsurfaces under the influence of external load. Fig. 1 shows the main characteristics of the standardgeometry of the rough surfaces: roughness with a maximum profile height of R max , the maximumcorrugation height Rw max and macrodeviation from horizontal base plane with height characteristic .143