A combined upper bound and finite element model for prediction of velocity and temperature fields during hot rolling process

In this work, velocity field and temperature distribution during hot strip rolling are predicted, employing a combined upper bound and finite element analysis. At first, a velocity field is proposed utilizing the principle of volume constancy, and then the velocity field is modified by means of upper bound theorem. At the same time, a thermal-finite element analysis is utilized to determine temperature distribution within the metal as well as to calculate the flow stress of deforming material. The model is capable of considering the effects of different factors on temperature and velocity distributions such as rolling speed and interface heat transfer coefficient. In order to verify the predictions, the calculated time–temperature curves as well as roll forces have been compared with the measured ones and a good agreement has been observed. The main advantage of the present model is that the model requires relatively lower computational effort in comparison with the required one in standard finite element codes.