A subroutine was developed and implemented to specify
the displacement field. With regard to the nodes that lie on
the hole surface, the subroutine reads the nodal coordinates
and evaluates the locally associated point on the implant analytical
surface. The displacement vector, corresponding to the
imposed press fit, is calculated as the difference between the
coordinates of the point on the implant surface and the coordinates
of the node itself. The displacement vector is effectively
applied only if the local diameter of the implant is greater than
the hole diameter.