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Interaction of a screw dislocation and an embedded nonuniformly coated circular fiber with imperfect interfaces

Kamali, M. T ; Sharif University of Technology | 2020

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  1. Type of Document: Article
  2. DOI: 10.1016/j.ijsolstr.2019.08.009
  3. Publisher: Elsevier Ltd , 2020
  4. Abstract:
  5. The eccentricity between the circular fiber and its coating as well as the imperfection at the fiber-coating-matrix interfaces associated with certain composites can have a remarkable effect on the movement of a dislocation. For an in-depth understanding of such phenomena, the present work provides an exact analytical solution for the interaction between an eccentrically coated circular inhomogeneity embedded in an infinite elastic medium with imperfect interfaces and a screw dislocation. The dislocation may be located inside one of the regions: the core inhomogeneity, coating, or the matrix. The corresponding boundary value problem is solved by using conformal mapping and complex potential functions. The potential function associated with each region consists of a singular term which is the same as in the case where the dislocation is inside an infinite homogeneous medium made from the material of that region and some appropriate regular terms due to the presence of the two-phase inhomogeneity of interest. The regular parts of the solutions corresponding to the core inhomogeneity, coating, and the matrix are represented by Laurent series. In the general case of the eccentrically coated circular inhomogeneity and imperfect interfaces, the imposition of boundary conditions leads to some recursive relations which are very effective for the calculation of the unknown coefficients. For two special cases where: (1) the interfaces are perfect but eccentric, (2) the interfaces are imperfect but concentric, the exact closed-form expressions for the coefficients are obtained. For different ratios of the rigidities of the fiber and coating to the rigidity of the matrix, the effects of the amount of the eccentricity and imperfection at the interfaces on the variation of the image force in terms of the dislocation position are examined. Also the equilibrium positions and the corresponding stability status are discussed. © 2019 Elsevier Ltd
  6. Keywords:
  7. Nonuniformly coated circular inhomogeneity ; Screw dislocation ; Boundary value problems ; Coatings ; Conformal mapping ; Rigidity ; Screw dislocations ; Screws ; Circular inhomogeneity ; Closed-form expression ; Complex variable analysis ; Equilibrium positions ; Exact analytical solutions ; Image force ; Imperfect interface ; In-depth understanding ; Fibers
  8. Source: International Journal of Solids and Structures ; Volume 182-183 , 2020 , Pages 295-306
  9. URL: https://www.sciencedirect.com/science/article/abs/pii/S0020768319303774