An enriched cohesive zone model to deal with brittle interfaces

Oscillations observed in the load-displacement response of brittle interfaces modeled by interface elements in a quasi-static finite element framework are artifacts of the discretization. While limit points of the oscillatory path can be followed by application of path-following techniques, sufficiently refining the mesh can smoothen the response so that the standard iterative Newton-Raphson method becomes applicable. In contrast to the mentioned strategies that lead to unacceptably high computational costs and a low efficiency, a process driven hierarchical extension is used to enrich the separation approximation in the process zone of a cohesive crack. Mobility of the enrichment within individual cohesive zone elements adapts the discretized domain to the physics governing the problem without a need for further mesh refinements. Numerical aspects of the enrichment are discussed on the basis of a simple mode I delamination problem.