A finite element investigation into a soft rolling contact supplied by a non-Newtonian ink

A non-Newtonian model to predict the elastohydrodynamic behaviour in a soft rolling contact has been developed and tested against experimental data. Experimental work was carried out on a printing unit in which a roller pair was instrumented with pressure transducers to record film pressure and the normal stress at the rubber-substrate interface. A power law equation was found to be adequate in modelling the positive pressure zone in the nip, but was not capable of describing the film rupture pressure adequately. The index and exponent in the power law affect nip behaviour significantly. A shear rate cut-off model was used successfully to avoid singularity in the viscosity field at the mid-thickness and was found not to affect the behaviour in the nip significantly. (Abstract quotes from original text)