A new model for thermal-mechanical coupled of gradient temperature rolling force based on geometrical unified yield criterion

In order to precisely describe the yield deformation behavior of various materials, a generalized yield criterion known as geometrical unified (GU) yield criterion is firstly established in this paper. Based on this yield criterion, an analytical rolling force model of gradient temperature rolling process was established, and the impact of the temperature field was taken into consideration. The GU yield criterion is a function of shear tension ratio, and the classical yield criteria can be obtained as its special cases. The gradient temperature rolling process of an ultraheavy plate was analyzed depending on the GU yield criterion, and the corresponding energy functional was established. In the meanwhile, the temperature field expression was developed by taking temperature permeability into account. Finally, the analytical model of the force and energy parameters of the gradient temperature rolling process was constructed by fusing the temperature field with the energy functional. The model can very precisely estimate the rolling force and rolling torque when compared to the measured data. The errors of the rolling force and rolling torque are less than 3.27 %.