Dağ, Serkan
Functionally graded materials (FGMs) are multi-phase inhomogeneous composites, possessing smooth spatial variations in certain physical properties of the constituents. Depending on the types of the constituent materials used in the processing of orthotropic FGMs, the influences of thermal and hygroscopic loadings could be rather significant. This study is directed towards developing a new computational fracture analysis technique for orthotropic FGMs that are under mixed-mode hygrothermal loading. The method is based on the use of the J-integral in conjunction with the asymptotic crack tip displacement fields. Developed computational technique is integrated into a finite element analysis software. Parametric analyses are carried out by considering an inclined edge crack in an orthotropic FGM layer that is subjected to the influence of hygrothermal loading. In order to be able to verify the proposed method, obtained results are compared to those computed via displacement correlation technique (DCT). Comparisons demonstrate that proposed technique leads to numerical results of high accuracy. Further results are provided to illustrate the influences of crack inclination angle and geometry on the temperature and the specific moisture concentration fields; and the modes I and II stress intensity factors.
12th ASME Biennial Conference on Engineering Systems Design and Analysis (ESDA2014)


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 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...
Sliding frictional contact between a rigid punch and a laterally graded elastic medium
Dağ, Serkan; Yidirim, Bora; Ozatag, A. Cihan (2009-11-01)
Analytical and computational methods are developed for contact mechanics analysis of functionally graded materials (FGMs) that possess elastic gradation in the lateral direction. In the analytical formulation, the problem of a laterally graded half-plane in sliding frictional contact with a rigid punch of an arbitrary profile is considered. The governing partial differential equations and the boundary conditions of the problem are satisfied through the use of Fourier transformation. The problem is then redu...
Hybrid finite element for analysis of functionally graded beams
Sarıtaş, Afşin; Soydas, Ozan (2017-01-01)
A hybrid finite element model is presented, where stiffness and mass distributions over a beam with functionally graded material (FGM) are accurately modeled for both elastic and inelastic material responses. Von Mises and Drucker-Prager plasticity models are implemented for metallic and ceramic parts of FGM, respectively. Three-dimensional stress-strain relations are solved by a general closest point projection algorithm, and then condensed to the dimensions of the beam element. Numerical examples and veri...
Mixed-mode stress intensity factors for an embedded crack in an orthotropic FGM coating
Dağ, Serkan; Erdogan, F. (2006-10-18)
Analytical and computational methods are developed to examine mixed-mode fracture behaviour of an orthotropic FGM coating bonded to a homogeneous substrate through a layer of a bond-coat. The coating is assumed to contain an embedded crack perpendicular to the direction of the material property gradation. First, an analytical solution is developed considering a perturbation problem. Using Fourier transform, the problem is reduced to a system of singular integral equations which are solved by means of an exp...
Citation Formats
S. TOPAL and S. Dağ, “MIXED-MODE HYGROTHERMAL FRACTURE ANALYSIS OF ORTHOTROPIC FUNCTIONALLY GRADED MATERIALS USING J-INTEGRAL,” presented at the 12th ASME Biennial Conference on Engineering Systems Design and Analysis (ESDA2014), Copenhagen, DENMARK, 2014, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/55858.