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Kaushik N Tirakannavar
Department of Mechanical and Aerospace Engineering, Carleton University
Dr. Kuiying Chen
Research Officer, National Research Council, Ottawa, Canada
Under the guidance of
Outline
Introduction
Introduction
Failure Mechanisms
Types of imperfections
The imperfections cause normal stresses to be developed at the interface which nucleate separations
Role of imperfection on buckling
Role of imperfections on nucleation and buckling
The influence of imperfections on buckling is given by Von Karman nonlinear plate equations.
Von Karman nonlinear equations
dXWWWn
mWWWn
]2[31
)2()2(
0
2/
0
22
2
022
))2cos(1(2 0
0 LXL
hW b
(1)
(2)
(3)
Equation solution procedure
Symbolic Integration in MATLAB
Trapezoidal rule:
Simpson’s rule:
Bisection method of numerical analysis
Results and Discussion
Variation of Energy Release Rate
Gmin is equal to the interface toughness of the material
Effect of imperfection amplitude
Effect of critical imperfection length
Experimental data from SEM
Isothermal conditions at 11000C
t = 100 hours
t = 500 hours
Initial crack formation Crack propagation
Spallation of thermal coating
t = 50 hours
Cyclic conditions for 200 cycles
Spallation of thermal coatings
Future Scope
Conclusion
