Pressure Distribution Under a Ball Impacting a Thin Lubricant Layer

A steel ball is dropped onto a glass plate covered by an oil droplet where impact occurs. A small manganin pressure transducer deposited on the plate and in the oil, enables pressure-time traces to be recorded at different points within the region of pressure. Their shapes are similar to those obtained under a steady ehl (elastohydrodynamic) rolling contact. Dimples are formed in each surface during the latter stages of the approach. These, together with the radial pressure distributions, are similar in shape to those obtained theoretically elsewhere. The nature of the pressure-time response suggest that no surface to surface contact occurs during the impact.