ZAMM ZEITSCHRIFT FÜR ANGEWANDTE MATHEMATIK UND MECHANIK, cilt.105, sa.7, ss.1-19, 2025 (SCI-Expanded)
In this study, partial closure of the crack in the functionally graded
(FG) layer under the effect of a single load from the upper and lower
surfaces has been investigated with the help of elasticity theory. In
the study, firstly, the stress and displacement expressions of the FG
layer have been obtained by using the basic equations of elasticity
theory and Fourier integral transforms. By applying the boundary
conditions determined for the problem to the stress and displacement
expressions, an equation system consisting of four equations with four
unknowns has been obtained, and as a result of the solution of this
equation system, the coefficients in the stress and displacement
expressions have been obtained depending on an unknown slope function.
The solution of the problem has been reduced to a singular integral
equation by writing these coefficients in the boundary condition not
used in obtaining the coefficients. Then, this non-dimensionalized
integral equation has been converted into an algebraic equation system
by Gauss–Chebyshev integration formulation, and the stress intensity
factor at the crack tip has been determined depending on the unknown
crack tip slope. The stress intensity factor has been calculated and
investigated for different values of the layer thickness to crack
closure length ratio, crack initiation and closure length ratio, load
intensity factor, stiffness parameter, and Kolosov constant.