Hi Bill,

Did you use any failure criteria within the Autodyn (explicit dynamic)?

As far as I know, Autodyn automatically deletes elements once a strain limit is reached (provided that this option is not disabled by the user).

In Workbench LS-DYNA, when you open Engineering Data, there are several failure models available under the Toolbox. In addition, check the MAT_ADD_EROSION under LS-DYNA External Model-MAT (also available under the Toolbox) which serves to erode or delete elements once a certain criterion is met.