Research Information System
Thesis Type: Doctorate
Institution Of The Thesis: Orta Doğu Teknik Üniversitesi, Faculty of Engineering, Department of Mechanical Engineering, Turkey
Approval Date: 2016
Student: ONUR ARSLAN
Supervisor: SERKAN DAĞ
Abstract:Analytic and computational studies are performed for contact problems of orthotropic functionally graded material (FGM) coatings which are bonded to isotropic homogeneous substrates without any interfacial defects. The orthotropic FGM coatings possess orhotrophic stiffness gradations through the coating thickness direction. The variations of each orthotropic stiffness constants are assumed to behave as exponential functions. In the analytical procedure, the problems of orthotropic graded coatings which are subjected to contact loads by an arbitrarily shaped inelastic stamp are examined under plane strain assumption. After getting the Navier equations of the elasticity problem, Fourier transformation techniques are used to determine the field expressions that satisfy the boundary conditions of the related problem. A deformation gradient on the contact region is used to obtain a singular integral equation (SIE) which is collocated through a discretization procedure on the roots of Chebyshev polynomials. Computational approach for the same contact problem is based on the finite element method in which the coating-substrate systems are divided into finite elements having the material parameters defined at their centroids. The results produced by using the analytical technique and the finite element method are compared to assess the accuracy achieved by both methods. Finally, the complete contact problems on the orthotropic homogeneneous coatings are also investigated .