Embedded crack modelling for cohesive material

Abstract

The embedded crack modelling has been an attractive approach complement to standard finite element method and was a field of active research for recent years. This thesis conveys an embedded tensile crack modelling using strong discontinuity approach for cohesive material. The advantage of the method in comparison with other methods like XFEM lies in the fact that it uses elemental enrichment instead of nodal enrichment. By proper design of enhanced strain mode, the elemental enrichment can be eliminated using static condensation. Therefore, the coherent structure of existing standard finite element code is maintained till not reduce the efficiency. In this contribution, a new approach for crack propagation criteria based on stress recovery technique is introduced. The results show notable dependency of the propagation path on stress resolution. Hence a better crack propagation and distribution via elements is obtained. The flexibility of the embedded crack model is demonstrated by the extension to three dimension in which the same methodology as in 2D is used. On the implementation details, a standard FEM code was developed by Java programming language. Following that, the embedded crack element inherits and extends from classical finite element. The code was designed in a flexible and extensible manner in order to incorporate further non-linearity in material and/or geometry of finite element. The speed of the code is enhanced by using native state-of-the-art external solver.