پرویز ملک زاده

Analytical transient analysis of a functionally graded (FG) coated cylindrical bar weakened by multiple radial cracks under torsional transient loading is presented. The solution corresponding to a Volterra-type screw dislocation is achieved using the Fourier and Laplace transforms in the spatial and temporal domains, respectively. The obtained dislocation stress field is used to develop singular integral equations in terms of the unknown dislocation density function for the evaluation of multiple radial cracks. The resulting Cauchy integral equations are reduced to a set of algebraic equations and are solved numerically to determine the dislocation density functions. The achieved results are employed to evaluate the dynamic stress intensity factors (DSIFs) at the crack tips and the torsional rigidity of the FG coated circular cross-section bar with multiple embedded radial cracks. In addition, several numerical examples are presented to verify the results and to explore the effects of transient loading, FG coating layer, cracks position and interaction between them on the DSIFs and torsional rigidity of the FG coated cracked bars.