Numerical Modeling of Paper Machine Roll Contact with Regenerative Out-Of-Roundness Excitation

The softened rolling contact of two paper machine rolls is considered. A regenerative excitation source can exists in the system due to the finite relaxation time of the roll cover polymer materials. The modeling of the rolls is described by multibody substructuring methodology and the polymer cover layer between the rolls in contact is modeled by contact spring reaction forces calculated according to the stiffness of the layer. The regenerative excitation is introduced to the system as a time delay term and it is calculated from the penetration history of the cover layer. The solution of the system equations is obtained by numerical time integration by utilizing the method of steps time delay equation solution procedure. Some numerical results are illustrated.