Search results for "cohesive interface"
showing 5 items of 5 documents
An elastic-damage nonlocal interface model
2005
A nonlocal elastic damage interface model is proposed
A symmetric tangent stiffness approach to cohesive mechanical interfaces in large displacements
2022
The present article proposes a formulation for a cohesive interface element in large displacement conditions. Theoretical and computational aspects, useful for an effective and efficient finite element implementation, are examined in details. A six-node (or higher) isoparametric interface element for two dimensional cohesive fracture propagation problems is developed. The element operators are consistently derived by a variational approach enforced in the current configuration, where a current frame is defined with axes tangential and normal to the middle line of the interface opening displacement gap. Under the constitutive assumption of small value of the modulus of the vector product bet…
Integration of finite displacement interface element in reference and current configurations
2017
In the present paper the non-linear behaviour of a solid body with embedded cohesive interfaces is examined in a finite displacements context. The principal target is the formulation of a two dimensional interface finite element which is referred to a local reference frame, defined by normal and tangential unit vectors to the interface middle surface. All the geometric operators, such as the interface elongation and the reference frame, are computed as function of the actual nodal displacements. The constitutive cohesive law is defined in terms of Helmholtz free energy for unit undeformed interface surface and, in order to obtain the same nodal force vector and stiffness matrix by the two i…
Multiple Surface Cracking and Debonding Failure for Thin Thermal Coatings
2019
Abstract A mechanical analysis of thin films of quasi-brittle materials used as thermal coatings for superalloy substrate is proposed. The study considers a bi-material element subjected to uniform tension formed by a thin layer of quasi-brittle material (typically a ceramic) bonded on an elastic substrate. The bounding between the coating film and the substrate is realized by a very thin primer which mechanically modeled as a zero thickness cohesive frictional interface. The analysis is developed by a non-linear finite element simulation in which, in order to consider damage size effects, a non-local isotropic damage model is adopted for the quasi-brittle coating. The results of the analys…
A 3D Cohesive interface for the delamination analysis of a stiff film on a soft elastic substrate and the wrinkling/buckling deformation modes
2018
The paper proposes a finite element systematic study of a mechanical system composed by a soft elastic substrate, subjected to a uniform state of compression, covered by a stiff thin film. This kind of problem is rather common for coating systems where layered materials with severe mismatch of elastic and thermal properties are largely employed. The specific mechanical problem stands on the concomitant competition between elastic wrinkling surface deformation and the nonlinear delamination that can develop at the interface between the thin film and the substrate. Both mechanical phenomena have their source in the nonlinear elastic buckling of the thin stiff film, which can be viewed as a th…