Discrete crack path prediction by an adaptive cohesive crack model

In this contribution, an enhancement of the numerical simulation methods for cohesive crack propagation within the finite element framework is introduced. Motivated by some fundamental drawbacks of the standard procedure, which is characterised by an initial implementation of cohesive surfaces, a novel algorithmic approach is presented which allows an adaptive incorporation of the cohesive elements depending on a crack growth criterion for structures with low crack growth rates. A new adaptive modification of the nodal coordinates and element boundaries on basis of the anticipated crack propagation direction defined by failure criteria enables furthermore the representation of arbitrary crack patterns. Following a detailed description of implementation and formulation aspects, the applicability of different fracture criteria with respect to a reliable prediction of the crack growth direction is investigated. Exemplary computations show the capabilities of the proposed methods in relation to conventional approaches and in comparison with experimental results.