Calculation of pressure distribution in EHD point contacts from experimentally determinated film thickness

In lubrication studies, film thickness is measured since 1963 using optical interferometry, but pressure distribution is also of great interest. Unfortunately, this parameter is very difficult to measure. This paper presents a new method for pressure evaluation based on an inverse elastic approach. This latter uses the film thickness field known precisely (±3 nm) by computerised treatment of interferograms. We present here the whole process, from the image to the pressure field. A complete error analysis is conducted: the pressure field is known within 5% and the spatial resolution is 3 grid steps, i.e. 6 μm.