Finite element modelling of a pressure feeder using direct shear test measurements.

An ongoing investigation described in the past three years has focussed on showing that prepared cane and bagasse behave like a soil and exhibit critical state behaviour. The measured mechanical behaviour has been used to determine material parameters for bagasse and to work towards a material model that reproduces that behaviour more closely. This paper seeks to apply the measured material parameters with improved material models to the modelling of the pressure feeder of an Australian six-roll mill, and to compare the predictions with the available measurements from a sugar factory. The predictions include compressive and shear stresses and strains in the bagasse mat moving through the rolls, as well as roll loads and torques. The predictions for the underfeed nip seemed realistic, while the predictions for the pressure feeder were poor. There are large compression and shear stresses and strains being experienced by the bagasse during the milling process, and their accurate prediction would be important to predict the overall loads and torques in a milling unit. A technique of using a modelled backstop to predict the maximum forces that a roll pair can generate under certain geometry and operating conditions has been outlined and could be quite useful for evaluating better designs, following further prediction improvements and validation with measurements. The lack of available measurements for individual rolls was seen as a significant impediment for validation of predictions and further effort should be made to collect that data.