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Stress intensity factors of multiple axisymmetric interface cracks in an isotropic layer with FGM coating under torsional loading

Tavakoli, A ; Sharif University of Technology | 2019

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  1. Type of Document: Article
  2. DOI: 10.1108/MMMS-01-2019-0024
  3. Publisher: Emerald Group Publishing Ltd , 2019
  4. Abstract:
  5. Purpose: The purpose of this paper is to provide a theoretical analysis of the fracture behavior of multiple axisymmetric interface cracks between a homogeneous isotropic layer and its functionally graded material (FGM) coating under torsional loading. Design/methodology/approach: In this paper, the authors employ the distributed dislocation technique to the stress analysis, an FGM coating-substrate system under torsional loading with multiple axisymmetric cracks consist of annular and penny-shaped cracks. First, with the aid of the Hankel transform, the stress fields in the homogeneous layer and its FGM coating are obtained. The problem is then reduced to a set of singular integral equations with a Cauchy-type singularity. Unknown dislocation density is achieved by numerical solution of these integral equations which are employed to calculate the SIFs. Findings: From the numerical results, the following key points were observed: first, for two types of the axisymmetric interface cracks, the SIFs decrease with growing in the values of the non-homogeneity. Second, the SIFs increase with increases in interface crack length. Third, the magnitude of the SIFs decreases with increases in the FGM coating thickness. Fourth, the interaction between cracks is an important factor affecting the SIFs of crack tips. Originality/value: New analytical dislocation solution in an FGM coating-substrate system is developed. © 2019, Emerald Publishing Limited
  6. Keywords:
  7. Axisymmetric interface cracks ; Isotropic layer ; SIFs ; Beams and girders ; Coatings ; Crack tips ; Fracture mechanics ; Functionally graded materials ; Integral equations ; Stress analysis ; Stress intensity factors ; Structural loads ; Thickness measurement ; Distributed dislocation technique ; Functionally graded coatings ; Interface crack ; Isotropic layers ; SIFs ; Loading
  8. Source: Multidiscipline Modeling in Materials and Structures ; Volume 15, Issue 6 , 2019 , Pages 1352-1365 ; 15736105 (ISSN)
  9. URL: https://www.emerald.com/insight/content/doi/10.1108/MMMS-01-2019-0024/full/html