Rolling Contact Mechanics of Graded Coatings Involving Frictional Heating

Nili Ahmadabadi, Ali | 2019

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 52007 (45)
  4. University: Sharif University of Technology
  5. Department: Aerospace Engineering
  6. Advisor(s): Adibnazari, Saeed; Karimzadeh, Ardavan
  7. Abstract:
  8. In this Thesis ,the two-dimensional thermoelastic tractive rolling contact problem for an FGM coated half-plane under the plane strain deformation is investigated. A rigid cylinder rolls on the surface of an FGM coated half-plane with constant translational velocity, generating frictional heat in the slip zones of the contact area. Thermo-mechanical properties of the FGM vary exponentially along the thickness. It is assumed that the contact area consists of a central stick zone and two slip zones of the same sign. The transfer matrix method and Fourier integral transform technique are used to achieve a system of two Cauchy singular integral equations. The associated governing equations are discretized by applying the Gauss-Chebyshev integration method in order to gain a set of linear algebraic equations. The effects of Peclet number, material grading ratios, friction coefficient and coupling effects on contact stresses and temperature distribution are discussed in details. As a summary of the results it can be stated that by increasing the linear speed of the roller and consequently increasing thermoelastic effects, temperature rises and in-plane stress decreases. Also by selecting a softer surface material of the coating in comparison with the half-plane material, temperature and hence thermal effects will increase. Furthermore, by increasing friction coefficient in constant Q/fP ratio, surface temperature sharply increases. By increasing the ratio of stiffness of the half-plane to that of the FGM surface, the results of the coupled solution will recede from that of decoupled solution in which the Goodman approximation is employed. Finally, it has been investigated that thermal effects in the rolling contact problem have negligible effects on normal and tangential tractions and creep ratio
  9. Keywords:
  10. Contact Mechanics ; Rolling Contact ; Thermoelastic Contact ; Functionally Graded Materials (FGM) ; Heat Transfer

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