The numerical modeling of rotor–stator rubbing in rotating machinery: a comprehensive review

The rotor–stator rubbing in rotating machinery generated as a consequence of rotor imbalance, shaft misalignment, and casing deformation is a potential threat to the machinery that seriously affects its performance. Timely prediction and correction of the rubbing are essential for the prolonged life of the machinery and its overall performance. A complete understanding of the system behavior during interaction is a great challenge for researchers working in the field of rotor dynamics. Rubbing phenomena involve complex contact nonlinearities and associated thermal effects, which makes the analysis very difficult. Research works in this field are started with the analysis of simple two degree-of-freedom models and now dealing with extensive three-dimensional finite element models. This paper provides a comprehensive review of different numerical models of rotor–stator rubbing with respect to their ability in simulating the actual response characteristics. A detailed description of contact modeling is also presented with the advantages and disadvantages of each model. Different methods for solving the numerical models are briefly explained. In addition, a commentary on different emerging techniques of rub identification is also reported. Finally, some informed recommendations on future directions are made by stating what lacks in the current research activities.