Contact mechanics of graded orthotropic coatings

Download

index.pdf

Date

2015

Author

Arslan, Onur

Metadata

Show full item record

Item Usage Stats

238
views

122
downloads

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 .

Subject Keywords

Functionally gradient materials., Surfaces (Technology)., Coating processes., Coatings.

URI

http://etd.lib.metu.edu.tr/upload/12619734/index.pdf
https://hdl.handle.net/11511/25419

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Mixed-mode fracture analysis of orthotropic FGM coatings under mechanical and thermal loads İlhan, Küçük Ayşe; Dağ, Serkan; Department of Mechanical Engineering (2007) In this study, it is aimed to investigate the mixed-mode fracture behavior of orthotropic functionally graded material (FGM) coatings bonded to a homogeneous substrate through a homogeneous bond-coat. Analytical and computational methods are used to solve the embedded cracking problems under mechanical or thermal loading conditions. It is assumed that the material property gradation of the FGM coating is in the thickness direction and cracks are parallel to the boundaries. The principal axes of orthotropy a...
Contact mechanics of graded materials: Analyses using singular integral equations Dağ, Serkan (2006-10-18) Contact stress distribution at an FGM surface is evaluated using an analytical technique based on the singular integral equations. An FGM half-plane is assumed to be in sliding contact with a rigid stamp of an arbitrary profile. The functionally graded medium is assumed to possess two-dimensional material property variations. Two independent nonhomogeneity constants are used to derive the governing partial differential equations. By using the integral transform techniques, all boundary conditions are satisf...
Mechanical modeling of Thin Films Bonded to Functionally Graded Materials GÜLER, MEHMET ALİ; Gulver, Yusuf Fuat; Dağ, Serkan (2008-09-25) In this study the contact problems of thin films bonded to Functionally Graded Materials (FGM) are considered. In these problems the loading consists of any one or combination of stresses caused by uniform temperature changes and temperature excursions, far field mechanical loading, and residual stresses resulting from film processing or in the manufacturing process of the graded coating. The primary interest in this study is in examining stress concentrations or singularities near the film ends for the pur...
Contact mechanics problem between an orthotropic graded coating and a rigid punch of an arbitrary profile ARSLAN, ONUR; Dağ, Serkan (Elsevier BV, 2018-01-01) Singular integral equation (SIE) and finite element methods are developed for sliding contact analysis of a finite thickness orthotropic graded coating, which is perfectly bonded to an isotropic substrate. Orthotropic stiffness coefficients of the coating vary exponentially through the coating thickness. The coating is assumed to be loaded by a frictional rigid punch of an arbitrary profile. In the SIE formulation, governing partial differential equations are derived in accordance with the theory of plane e...
FRICTION AND WEAR BEHAVIOR OF SELECTED DENTAL CERAMICS PARK, JONGEE; PEKKAN, Gürel; Öztürk, Abdullah (World Scientific Pub Co Pte Lt, 2009-10-01) The purpose of this study was to determine the friction coefficients and wear rates of six commercially available dental ceramics including IPS Empress 2 (E2), Cergo Pressable Ceramic (CPC), Cercon Ceram (CCS) and Super porcelain EX-3 (SPE). Bovine enamel (BE) was also tested as a reference material for comparison purposes. Samples of the dental ceramics were prepared according to the instructions described by the manufacturers in disk-shape with nominal dimensions of 12 mm x 2 mm. The wear tests were perfo...

Citation Formats

O. Arslan, “Contact mechanics of graded orthotropic coatings,” Ph.D. - Doctoral Program, Middle East Technical University, 2015.