In the paper, a model for the physical phenomenon of fracture in a continuum medium is presented. The proposed formulation falls in the context of the Strong Discontinuities Approach (SDA) implemented by means of Elements with Embedded Discontinuities (EED). In the contribution, an improved enhanced displacement field is proposed, such that the displacement jumps are not constant within each finite element. In this way, by means of an appropriate choice of the interface degrees of freedom, the crack path and the displacement jumps can be modeled as continuous functions across the element boundaries. First the general thermodynamically consistent weak formulation is presented. It derives from a mixed generalized multi-fields Hu-Washizu functional based on the enriched kinematics. The continuum and the interface are ruled by different constitutive equations, defined by distinct free energy and dissipation functionals. Then, in the spirit of the EED approach, the non linear evolution problem in the continuum and at the interface is solved by means of a local algorithm, at the Finite Element level, that yields simultaneously the amplitude of the jump increment, the stress value at the Gauss points of the element and the traction on the interface surface. The performance of different enriched finite elements using different degrees of interpolation for either the regular and the enhanced fields, and thus considering constant and non constant jumps, are compared through some 2D applications.
|Titolo:||Finite Elements with non-Homogeneous Embedded Discontinuities|
|Data di pubblicazione:||2012|
|Appare nelle tipologie:||4.1 Contributo in Atti di convegno|