In many situations, initial clearances between two contact surfaces can cause convergence issues in IMPLICIT analyses while wasting simulation time in EXPLICIT analyses. To remove the initial contact clearance, LS-DYNA offers a capability using *CONTACT_AUTO_MOVE that helps to improve convergence in IMPLICIT analyses since contact is detected immediately.

Contact AUTO_MOVE associates itself with another contact (two-way and one-way ONLY) and
attempts to move the MASTER nodes during the initialization(cycle 0) such that the minimum
clearance is 0.5*0.5*(slave_thickness+master_thickness). This causes LS-DYNA to see an
initial penetration of 0.5*(slave_thickness+master_thickness) at cycle 1 causing both slave
and master segments to receive forces from the contact algorithm.

Notes

• To overcome the movement of both surfaces, you can turn on IGNORE=1 either in *CONTROL_CONTACT
  or at the *CONTACT level.
• AUTO_MOVE only works with one-way and two-way contact types

Here is a link to a simple example.