Numerical and Analytical Investigation of the Sandwich Sheet Rolling Process Considering Coulomb Friction

The rolling process is an economic and efficient approach for production of the sandwich sheets. In this research sandwich sheet rolling process is investigated using an analytical method (slab method) and a numerical approach (finite element method). Rigid-perfect plastic material behaviour and coulomb friction model were used in both analysing approaches. Because of the plain strain condition, the process is analysed as 2-dimentioal problem. The horizontal stress distribution in the layers, the rolling pressure along the contact interface and the neutral point between the roll and the sheet are investigated. Then the effects of the process parameters such as friction between the sheet and the roll, shear yield stress ratio of the matrix and clad layers, front and back tensions on the rolling characteristics such as the pressure and neutral point position are studied. The results demonstrate that the finite element method results are very near to the slab method results and extra simplifying assumptions in the slab method cause low deviation in the results. In both methods as the friction coefficient increases, the rolling pressure increases and the neutral point approaches the entrance of the roll gap. As the shear yield stress ratio increases, the rolling pressure increases but the neutral point is not shifted. As the front or back tensions are applied on the sandwich sheet, the rolling pressure decreases and the neutral point is shifted inverse of the tensions direction.