The complete measurement of hydrodynamic lubrication film pressure in both axial and circumferential directions is a key element in validating hydrodynamic journal bearing models. For this purpose, we employ an innovative measurement system that integrates piezoelectric pressure sensors directly into the shaft. During operation, the bearing is loaded and moved over the sensor, allowing for full-field pressure acquisition across the entire lubrication contact – under realistic conditions and with high temporal and spatial resolution. Measurements are taken in 0.45° increments at rotational speeds of up to 18,000 rpm, corresponding to a circumferential speed of approximately 100 m/s.
This method is particularly valuable for assessing the influence of compliant bearing surfaces, such as polymer-based running layers. These materials often result in a more uniform pressure distribution within the lubrication film. However, under certain operating conditions, they may also lead to edge-loading phenomena, which can promote bearing failure.
Thanks to the ability to fully capture the pressure distribution during operation, even plastic deformations – such as the flow of white metal – can be detected and analyzed. This opens up new possibilities for the design, optimization, and durability assessment of modern journal bearing technologies.