Investigation on comparisons between two analytical models of sandwich sheet rolling bonded before rolling

Two analytical models proposed are to get the stress field of sandwich sheet rolling at the roll gap by using the slab method in order to compare the both rolling characteristics. The first model (model I) assumes the friction between the rolls and the sandwich sheet to be Coulomb friction, and the second model (model II) assumes the friction to be constant shear friction. The neutral point between the roll and sandwich sheet, the rolling pressure distribution, the horizontal stresses in the component layers of the sandwich sheet, the shear stress at the interface of the sandwich sheet, the rolling force and rolling torque, etc., can be easily calculated by using these analytical models. These rolling characteristics of the sandwich sheet rolling, which are affected by various rolling conditions such as the sandwich thickness ratio, the shear yield stress ratio, the frictional coefficients (or the frictional factors), the reduction, etc., are analyzed systematically. The differences between these two models are clearly investigated by the study. The relationships between frictional coefficient and frictional factor under the rolling condition are derived, and limit frictional coefficient generating sticking friction can be obtained effectively. These complete formulae are used to offer effective knowledge to the rolling industry.