Description: As in past releases of Abaqus/Standard, all points in contact (i.e., with a “closed” status) are assumed to be sticking during linear perturbation steps if friction is present, except contact nodes for which a velocity differential is imposed by the motion of the reference frame or the transport velocity. Stick conditions are enforced with a penalty method by default; you can now apply a scale factor to this penalty stiffness. For example, setting the scale factor to zero will result in zero penalty stiffness, such that the stick conditions are not enforced during the perturbation step. Setting the scale factor to a value greater than unity results in a larger-than-default penalty stiffness, and thus stricter enforcement of stick conditions during the perturbation step. For example, the amount of compliance associated with tangential interface constraints can significantly affect natural frequencies and eigenmodes.