IMT Institutional Repository: No conditions. Results ordered -Date Deposited. 2024-05-23T13:29:55ZEPrintshttp://eprints.imtlucca.it/images/logowhite.pnghttp://eprints.imtlucca.it/2016-03-15T10:30:26Z2016-03-15T10:30:26Zhttp://eprints.imtlucca.it/id/eprint/3238This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/32382016-03-15T10:30:26ZInterfacial cracks in bi-materials solids: Stroh
formalism and skew-symmetric weight functionsLorenzo Morinilorenzo.morini@imtlucca.itEnrico RadiAlexander MovchanNatalia Movchan2016-03-14T14:23:16Z2016-03-14T14:23:16Zhttp://eprints.imtlucca.it/id/eprint/3229This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/32292016-03-14T14:23:16ZStroh formalism in analysis of skew-symmetric and symmetric weight functions for interfacial cracksThe focus of the article is on analysis of skew-symmetric weight matrix functions for interfacial cracks in two dimensional anisotropic solids. It is shown that the Stroh formalism proves to be an efficient approach to this challenging task. Conventionally, the weight functions, both symmetric and skew-symmetric, can be identified as a non-trivial singular solutions of the homogeneous boundary value problem for a solid with a crack. For a semi-infinite crack, the problem can be reduced to solving a matrix Wiener-Hopf functional equation. Instead, the Stroh matrix representation of displacements and tractions, combined with a Riemann-Hilbert formulation, is used to obtain an algebraic eigenvalue problem, that is solved in a closed form. The proposed general method is applied to the case of a quasi-static semi-infinite crack propagation between two dissimilar orthotropic media: explicit expressions for the weight matrix functions are evaluated and then used in the computation of complex stress intensity factor corresponding to an asymmetric load acting on the crack faces.Lorenzo Morinilorenzo.morini@imtlucca.itEnrico RadiAlexander MovchanNatalia Movchan2016-03-14T14:17:09Z2016-03-14T14:17:09Zhttp://eprints.imtlucca.it/id/eprint/3227This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/32272016-03-14T14:17:09ZIntegral identities for a semi-infinite interfacial crack in anisotropic elastic bimaterialsThe focus of the article is on the analysis of a semi-infinite crack at the interface between two dissimilar anisotropic elastic materials, loaded by a general asymmetrical system of forces acting on the crack faces. Recently derived symmetric and skew-symmetric weight function matrices are introduced for both plane strain and antiplane shear cracks, and used together with the fundamental reciprocal identity (Betti formula) in order to formulate the elastic fracture problem in terms of singular integral equations relating the applied loading and the resulting crack opening. The proposed compact formulation can be used to solve many problems in linear elastic fracture mechanics (for example various classic crack problems in homogeneous and heterogeneous anisotropic media, as piezoceramics or composite materials). This formulation is also fundamental in many multifield theories, where the elastic problem is coupled with other concurrent physical phenomena.Lorenzo Morinilorenzo.morini@imtlucca.itAmdrea PiccolroazGennady MishurisEnrico Radi2016-03-11T13:18:00Z2016-03-11T13:18:00Zhttp://eprints.imtlucca.it/id/eprint/3221This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/32212016-03-11T13:18:00ZOn fracture criteria for dynamic crack propagation in elastic materials with couple stressesThe focus of the article is on fracture criteria for dynamic crack propagation in elastic materials with microstructures. Steady-state propagation of a Mode III semi-infinite crack subject to loading applied on the crack surfaces is considered. The micropolar behavior of the material is described by the theory of couple-stress elasticity developed by Koiter. This constitutive model includes the characteristic lengths in bending and torsion, and thus it is able to account for the underlying microstructures of the material. Both translational and micro-rotational inertial terms are included in the balance equations, and the behavior of the solution near to the crack tip is investigated by means of an asymptotic analysis. The asymptotic fields are used to evaluate the dynamic J-integral for a couple-stress material, and the energy release rate is derived by the corresponding conservation law. The propagation stability is studied according to the energy-based Griffith criterion and the obtained results are compared to those derived by the application of the maximum total shear stress criterion.Lorenzo Morinilorenzo.morini@imtlucca.itAmdrea PiccolroazGennady MishurisEnrico Radi2016-03-11T12:10:25Z2016-05-04T09:55:02Zhttp://eprints.imtlucca.it/id/eprint/3214This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/32142016-03-11T12:10:25ZConservation integrals for two circular holes kept at different temperatures in a thermoelastic solidAbstract An explicit analytic solution for thermal stresses in an infinite thermoelastic medium with two circular cylindrical holes of different sizes kept at different constant temperatures, under steady-state heat flux is presented. The solution is obtained by using the most general representation of a biharmonic function in bipolar coordinates. The stress field is decomposed into the sum of a particular stress field induced by the steady-state temperature distribution and an auxiliary isothermal stress field required to satisfy the boundary conditions on the holes. The variations of the stress concentration factor on the surface of the holes are determined for varying geometry of the holes. The concept of the conservation integrals Jk, M and L is extended to steady state thermoelasticity and the integrals are proved to be path-independent. These integrals are calculated on closed contours encircling one or both holes. The geometries of a hole in a half-space and an eccentric annular cylinder are considered as particular cases.Enrico RadiLorenzo Morinilorenzo.morini@imtlucca.itI. Sevostianov