Dynamic Cohesive Element Insertion

In many dynamic fracture problems we are not able to easily predict the cohesive failure locations or paths. And so, for conservative CVFE analysis, the domain is discretized with cohesive elements everywhere from the beginning. As a result, these problems incur the greatest computational costs, especially if actual cohesive failures do not occur until late in the simulation. A preferred approach is to place cohesive elements anywhere and at any time during a simulation. In this way, we are able to save much computational effort since cohesive elements won't be inserted until they are needed. We present this dynamic insertion method using blind insertion, damping and pre-stretching of cohesive elements on a simple 2-D problem. We then apply the algorithm, using the two aforementioned selection methods: the bounding box method and the stress based stress-based approach to several problems.