Thermal stress intensity factor evaluation for inclined cracks in functionally graded materials using Jk-integral method

Demirçivi, Bengi
The main objective of this study is to evaluate mixed mode stress intensity factors for inclined embedded cracks in functionally graded materials. Fracture analysis of inclined cracks requires the calculation of both Mode I and Mode II stress intensity factors ( I K , II K ). In this study, k J -integral is used to calculate I K and II K . Equivalent domain integral approach is utilized to evaluate the k J - integral around the crack tip. The present study aims at developing a finite element model to study inclined crack problems in graded media under thermomechanical loading. A two dimensional finite element model is developed for inclined cracks located in a functionally graded medium. Structural and thermal problems are solved using two dimensional finite elements namely 8- noded triangles. Material properties are sampled directly at the integration points of the elements, as required by the numerical integral evaluation. The main results of the study are the stress intensity factors at the crack tip for functionally graded materials subjected to thermomechanical loading.


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Balcı, Mehmet Nurullah; Dağ, Serkan; Department of Mechanical Engineering (2018)
The main aim of this study is to analyze the dynamic frictional contact problem of layered and functionally graded materials. Investigating contact problems including dynamic effects has a significant importance in mechanical engineering applications since many contact problems arise between moving structures. In moving contact problems, speed of the punch may not be so small to ignore dynamic effects. Hence, contact problem should be examined using elastodynamics theory. In this study, both frictional movi...
Three dimensional fracture analysis of FGM coatings under thermomechanical loading
Yildirim, B; Dağ, Serkan; Erdogan, E (Springer Science and Business Media LLC, 2005-04-01)
The main objective of this study is to examine the three dimensional surface crack problems in functionally graded coatings subjected to mode I mechanical or transient thermal loading. The surface cracks are assumed to have a semi-elliptical crack front profile of arbitrary aspect ratio. The cracks are embedded in the functionally graded material (FGM) coating which is perfectly bonded to a homogeneous substrate. A three dimensional finite element method is used to solve the thermal and structural problems....
Frictionless double contact problem for an axisymmetric elastic layer between an elastic stamp and a flat support with a circular hole
Mert, Oya; Geçit, M. Ruşen; Department of Engineering Sciences (2011)
This study considers the elastostatic contact problem of a semi-infinite cylinder. The cylinder is compressed against a layer lying on a rigid foundation. There is a sharp-edged circular hole in the middle of the foundation. It is assumed that all the contacting surfaces are frictionless and only compressive normal tractions can be transmitted through the interfaces. The contact along interfaces of the elastic layer and the rigid foundation forms a circular area of which outer diameter is unknown. The probl...
Stress distributions in elastic-plastic rotating disks with elliptical thickness profiles using Tresca and von Mises criteria
Eraslan, Ahmet Nedim (Wiley, 2005-04-01)
Analytical and numerical solutions for the elastic-plastic stress distribution in rotating variable thickness solid and annular disks are obtained under plane stress assumption. The thickness of the disk is assumed to vary radially in elliptic form which represents a wide range of continuously variable nonlinear cross-sectional profiles. Tresca's yield criterion and its associated flow rule are used to obtain analytical solutions for a linear hardening material. A computational model is developed to obtain ...
Fatigue crack growth analysis models for functionally graded materials
Dağ, Serkan; YILDIRIM, BORA (2006-10-18)
The objective of this study is to develop crack growth analysis methods for functionally graded materials (FGMs) subjected to mode I cyclic loading. The study presents finite elements based computational procedures for both two and three dimensional problems to examine fatigue crack growth in functionally graded materials. Developed methods allow the computation of crack length and generation of crack front profile for a graded medium subjected to fluctuating stresses. The results presented for an elliptica...
Citation Formats
B. Demirçivi, “Thermal stress intensity factor evaluation for inclined cracks in functionally graded materials using Jk-integral method,” M.S. - Master of Science, Middle East Technical University, 2006.