Rheological Model of the Sheet Drywall Forming Process
Statement of the problem. The paper investigates the problem of the formation of gypsum mixture (sludge), which is the most important technological component of the manufacturing process of sheet drywall. The solution is carried out within the framework of a rheological model of the isothermal, stationary flow of an incompressible Bingham medium in a flat channel between parallel planes under conditions of an abrupt change in the pressure gradient. Assuming the simultaneous presence of shear (viscous) and plastic (quasi-solid) flow regions, the stress-strain state of the medium is studied separately for each of them. From the condition of equality in magnitude of the intensity of stress in the shear and tangential - in the plastic regions, the coordinate of the interface of these regions is determined. A pressure drop is determined at which the Bingham medium behaves like a plastic body, and when its limit value is exceeded, a viscous flow zone appears along with the plastic region. Results and Conclusions. Analytical expressions are obtained for the flow velocity and tangential stresses arising during the molding of the gypsum mixture depending on the thickness of the deformed layer.