טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
Ph.D Thesis
Ph.D StudentShinkarenko Alexey
SubjectSoft Elastohydrodynamic Lubrication
DepartmentDepartment of Mechanical Engineering
Supervisors Dr. Yuri Kligerman
Professor Emeritus Izhak Etsion
Full Thesis textFull thesis text - English Version


Abstract

Soft Elasto-Hydrodynamic Lubrication (SEHL) is used in several mechanical components like rotary lip seals, elastomeric reciprocating seals, metering size press etc. Until the last decade most studies of SEHL were of experimental nature only because of the complexity of the problem. The first extensive theoretical investigations of SEHL appeared in the literature only about ten years ago thanks to the rapid development of computing capabilities. In most of those studies, the surface topography consisted mainly of traditional non-regular surface roughness rather than designed regular textured surfaces, which can enhance the tribological performance of the SEHL component.

            In the present study a theoretical model is developed to study the potential use of surface texturing in the form of spherical micro-dimples for SEHL. The model consists of elastomeric and rigid surfaces moving relative to each other in the presence of a viscous lubricant.  The texturing can be applied either to the soft elastomer or to the rigid counter face. The pressure distribution in the fluid film and the elastic deformations of the elastomer are obtained from a simultaneous solution of the Reynolds equation and the equation of elasticity for the elastomer. An extensive parametric investigation is performed to identify the main important parameters of the problem, which are the aspect ratio and area density of the dimples. The parametric analysis provides optimum parameters of the surface texturing (dimple depth over dimple diameter ratio and dimple area density), which effectively increase load capacity and reduce friction in SEHL.