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Investigation of Effective Parameters in Contact Mechanics of FGM Coated Half-Space through FEM Modeling

Khajehtourian, Romik | 2011

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 42735 (45)
  4. University: Sharif University of Technology
  5. Department: Aerospace Engineering
  6. Advisor(s): Adib Nazari, Saeed
  7. Abstract:
  8. In this research, the surface contact and lateral stress distribution due to the contact between a rigid flat punch and a FG coating is investigated through macro and micro mechanical modeling due to FEM. The effects of important parameters in modeling of contact mechanics, both macro mechanically and micromechanically investigated. Study of such parameters is important, especially in fracture mechanics point of view, since stress distribution of mechanical contacts can cause the crack nucleation and evolution and finally catastrophic failure. Investigating the effective parameters in FEM models and analyzing the result admittedly help to improve manufacturing methods in order to smooth the stress distribution in FGMs. The geometry of the model includes two parts: the FGM layer on the top and a homogenous substrate which is connected to FGM coating. Commonly, in FGM studies, the homogenous substrate has the metallic interface with the FGM coating and as the FGM thickness increases its characterization gradually varies till it approaches to a ceramic in contact surface. It is assumed that the thickness variation of the mechanical properties of FGM coating is exponential. Also the Poisson’ ratio can be considered constant or varying through the thickness. The optimum number of macromechanical FGM coating layer is found. Also, the FGM thickness, the thickness variation of mechanical properties and the homogenization methods studied. In the micromechanical model, the random arrangements of particles and its effects on stress distribution investigated. In addition, the particle size, the particle aspect ratio and the repetition of a specific arrangement of particle in contact surface and their relation to stress distribution studied
  9. Keywords:
  10. Contact Mechanics ; Functionally Graded Materials (FGM) ; Micromechanical Model ; Homogenization ; Macro Mechanical Model

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