Directional frequency response applied to wear identification in hydrodynamic bearings

• Wear model on hydrodynamic journal bearings.
• Sensitivity of the directional frequency response function (dFRF) due to wear.
• Advantages of using the dFRF when compared with the FRF in the analysis of worn bearings.
• Wear parameters identification in hydrodynamic bearings.

This work analyzes the influence of the wear in hydrodynamic bearings in the directional frequency response of a rotating system. Previous works presented a numerical approach to identify the bearing wear parameters using the unbalance response of the system in different rotational speeds. In continuity, this paper analyzes the directional frequency response function (dFRF) to identify the wear model, prompting a feasible application of the method, taken into account that it is not possible to operate the rotor near the critical speeds. The results show that the dFRF matrix is sensitive to the wear parameters and more suitable for bearing wear identification, based on the cross-coupled terms of the dFRF matrix, which present a higher sensitivity to the bearing wear.