Bill Bulat
Ansys Employee

Was this analysis performed with Abaqus Explicit?

MAPDL technology is strictly implicit. Even if we "kill" (deactivate) elements (using the MAPDL EKILL command) as the solution progresses (using, say, some kind of limiting stress as a criterion for element deactivation), the deactivated elements are retained... they will continue to be used in the formulation of the system matrices. The failed elements will almost certainly become "entangled" - it will be impossible to formulate global stiffness matrix based on severely mishapen elements (e.g., vertices get pushed though element faces/edges on the opposite side). When that happens it's game over - the simulation will end with an element formulation error.

We have a couple of explicit solvers that are almost always much better suited to an impact + ultimate failure simulation such as this. They allow the specification of limiting failure stresses which, when exceeded, result in the elimination of the element entirely (so the simulation can proceed).