In the presence of contact the convergence conditions in the previous section are slightly modified. Let us first repeat the general convergence check strategy (coded in checkconvergence.c):

In the case penalty contact was defined an additional parameter iflagact is defined expressing whether the number of contact elements changed significantly between the present and the previous iteration. In the latter case iflagact=1, else it takes the value zero (default). Whether a change is significantly or not is governed by the value of the parameter delcon, which the user can define underneath a *CONTROLS,PARAMETERS=CONTACT card (default is 0.001, i.e. 0.1 %).

Now, in the case of node-to-face penalty contact the standard convergence check algorithm is modified as follows:

In the case of face-to-face penalty contact the criteria are modified as follows: