Three Dimensional Modeling of Inclined Surface Cracks in FGM Coatings

Kosker, S.
Dağ, Serkan
This study presents a three dimensional finite element method for mixed-mode fracture analysis of an FGM coating-bond coat-substrate structure. The FGM coating is assumed to contain an inclined semi-elliptical crack at the free surface. The trilayer structure is examined under the effect of transient thermal stresses. Strain singularity around the crack front is simulated by utilizing collapsed wedge-shaped singular elements. The modes I, II and III stress intensity factors are computed by applying the displacement correlation technique and presented as a function of time. Four different FGM coating types are examined in the parametric analyses which are metal-rich, ceramic-rich, linear variation and homogeneous coatings. The results provided illustrate the influences of the FGM coating type and crack inclination angle on the transient behavior of the mixed-mode stress intensity factors.


Mixed-mode fracture analysis of orthotropic functionally graded material coatings using analytical and computational methods
Dağ, Serkan (ASME International, 2008-09-01)
This article presents analytical and computational methods for mixed-mode fracture analysis of an orthotropic functionally graded material (FGM) coating-bond coat-substrate structure. The analytical solution is developed by considering an embedded crack in the orthotropic FGM coating. The embedded crack is assumed to be loaded through arbitrary self-equilibrating mixed-mode tractions that are applied to its surfaces. Governing partial differential equations for each of the layers in the trilayer structure a...
Computational Methods for Inclined Cracks in Orthotropic Functionally Graded Materials Under Thermal Stresses
Dağ, Serkan; TOPAL, SERRA (2013-10-03)
This article sets forth two different computational methods developed to evaluate fracture parameters for inclined cracks lying in orthotropic functionally graded materials, that are under the effect of thermal stresses. The first method is based on the J(k)-integral, whereas the second entails the use of the J(1)-integral and the asymptotic displacement fields. The procedures introduced are implemented by means of the finite element method and integrated into a general purpose finite element analysis softw...
Three dimensional analysis of periodic cracking in FGM coatings under thermal stresses
Dağ, Serkan; Erdogan, Fazil (2006-10-18)
A three dimensional finite element method is used to examine periodic surface cracking problem in a functionally graded coating subjected to transient thermal loads. The ceramic/metal FGM coating is assumed to contain periodic semi-elliptical cracks and to be perfectly bonded to a homogeneous substrate. The composite structure is subjected to transient residual/thermal stresses. Temperature and displacement fields are computed using a three dimensional finite element approach. Finite element models are crea...
Three dimensional fracture analysis of FGM coatings
Inan, O; Dağ, Serkan; Erdogan, F (2005-01-01)
In this study the three - dimensional surface cracking of a graded coating bonded to a homogeneous substrate is considered. The main objective is to model the subcritical crack growth process in the coated medium under a cyclic mechanical or thermal loading. Because of symmetry, along the crack front conditions of mode I fracture and plane strain deformations are assumed to be satisfied. Thus, at a given location on the crack front the crack propagation rate would be a function of the mode I stress intensit...
Computational elastodynamics of functionally graded thick-walled cylinders and annular coatings subjected to pressure shocks
Abeidi, Abdelrahim; Dağ, Serkan (2022-12-01)
A computational technique based on domain-boundary element method (D-BEM) is developed for elastodynamic analysis of functionally graded thick-walled cylinders and annular coatings subjected to pressure shock type of loadings. The formulation is built on the wave equation, which is derived in accordance with plane elastody-namics. Weighted residual statement for the wave equation is expressed by using the static fundamental solution as the weight function. Applying integration by parts and incorporating the...
Citation Formats
S. Kosker, S. Dağ, and B. YILDIRIM, “Three Dimensional Modeling of Inclined Surface Cracks in FGM Coatings,” 2008, Accessed: 00, 2020. [Online]. Available: