A combined experimental and numerical investigation into the behaviour at the nip formed by the junction of a hard and soft elastomer covered roller is described. Experimental measurement of pressure at the film and elastomer-substrate interface are presented along with the speed differential due to microslip and thermal transients due to elastomer hysteresis. A unified finite element model of the nip is also presented where Newtonian behaviour is adopted to reflect the use of a gear oil as the lubricant in the experimental work. The system response was found to be dependent on engagement, contact width, surface speed and elastomer properties in particular. It was found that this contact type cannot be described accurately with a Hertzian model which has been adopted in all previous studies.

A study of numerical modelling and experiments of a soft rolling nip contact is described. 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 were noted to affect nip behaviour significantly and similarly. 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.

The contact behaviour in a coating roller or printing press roller nip is investigated in this paper by using soft elastohydrodynamic lubrication (EHL) theory. Film thickness, roller deformation and pressure profiles are evaluated for a range of possible dimensionless speed, load, elastomer thickness, Poisson's ratio and fluid inlet positions. To achieve the simultaneous iterative solution of the describing equations, the Reynolds equation is transformed into a form of boundary integral equation which is solved by Simpson's rule and surface distortion is obtained by a boundary element method. The numerical scheme proved to be very effective for such layered soft EHL problems. Results show that relatively thick fluid films exist in the nip because of the large deformation of the elastomer under normal working conditions. The dimensionless speed parameter has more influence on film formation at a fully flooded condition than any of the other parameters. Because the layer is easily deformable, film thickness may increase when load increases. The shape and thickness of the film and pressure profile are also controlled by the degree of starvation. At severely starved fluid supply, speed and load parameters have the most significant effect on the minimum film thickness. Larger Poisson's ratios produce a little smaller film thicknesses and larger surface displacements than the small values, and small elastomer thickness gives small indentation and large pressures in the nip.