טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentZolotarevskiy Vadim
SubjectThe Effect of Tangential Loading on Tribological Phenomena
in Spherical Contact
DepartmentDepartment of Mechanical Engineering
Supervisors Professor Emeritus Izhak Etsion
Dr. Yuri Kligerman
Full Thesis textFull thesis text - English Version


Abstract

The problem of an elastic-plastic hemisphere in contact with a flat under tangential loading is numerically analyzed assuming full stick contact condition. Unidirectional and cyclic tangential loading are studied in pre-sliding regime.
For the unidirectional tangential loading the evolution of static friction and tangential stiffness is investigated. Empirical dimensionless equations are developed for these parameters.

For the cyclic tangential loading, aspects like different hardening laws, slip index, energy dissipation, normal load and mechanical properties of the hemisphere are studied. It is found that the slip index and the dissipated energy, calculated from numerically obtained friction-displacement loops, are qualitatively similar to corresponding recently published experimental results. In addition it is found that an increase in dimensionless normal load, and also independently in the ratio of elastic modulus over yield strength, leads to an increase in the dimensionless dissipated energy. An empirical expression to predict dissipated energy is derived, showing good agreement with the numerical model prediction.