Non steady abaqus rolling simulation

Hi all,


When running a rolling simulation in Abaqus/Standard I have strange roll force/torque behaviour (see screenshot).

My only way of reasoning with this is that the sheet hasn't reached a steady state yet but from the second screenshot we can see that a large portion of the sheet has been rolled so I would expect the force/torque to have flattened off at some stage.

Anyone have any idea why this is happening?