Edge to Edge Impact Locking

Interface TYPE7 does not deal with edge to edge impact. The limitation of this interface during the edge to edge contact is illustrated in Figure 1.

Figure 1. Edge to Edge Contact
When the mesh is fine enough, edge to edge penetration is often followed by a node to shell contact. The main problem with edge to edge impact is the locking situations. If there is a change of load after edge penetration, locking is unavoidable since a node to surface contact is detected (Figure 2). This usually leads to high penetration; therefore, the analysis comes to a standstill as time step is reduced. If locking occurs, the use of interface TYPE11 in this area is necessary to solve the problem.

Figure 2. Locking After Edge Penetration