Modelling Cracks the Easy Way
In my previous blog I talked about the advantages of automatic re-meshing in the analysis of rubbers in improving accuracy and stability of a simulation. One advanced application of this capability that was not touched upon was in the field of crack propagation.
In many industries it is sufficient to use your analysis to predict that a crack could initiate and redesign the part to avoid this occurrence. In others though it is possible that a crack may be identified from an in-service inspection whereupon it becomes necessary to understand if it will propagate under the loads applied and how quickly so that a replacement can be introduced in a timely manner.
Predicting crack growth in materials with finite elements can seem more art than science.
As an example, in some codes you may need to construct a very precise ‘rosette’ mesh at the crack tip.
A series of angular perturbations to the crack tip node are then simulated to look at the energy release resulting from extending the tip with the assumption being it moves in the direction of the greatest energy release.