Modeling of hydrodynamic bearing wear in rotor-bearing systems

2016

An. Acad. Bras. Ciênc.

Self Cite

The present work gives continuity in the analysis of the wear influence on cylindrical hydrodynamic bearings by presenting an experimental validation of the wear model previously proposed by the authors. This validation is carried on using the frequency response of the rotor-bearings system in directional coordinates. For this purpose, a test rig was assembled in order to evaluate the behavior of the rotating system when supported by hydrodynamic bearings with different wear patterns. The experimental measurements are used to validate the wear model, comparing the anisotropy influence on the experimental and numerical responses. The simulated directional frequency responses showed a good agreement with the experimental ones, demonstrating the potential of the proposed wear model in satisfactorily represent its influence on the rotor-bearings system response in the frequency range where the numerical model was validated.

Section: Experimental Validation Of a Bearing Wear Model 2403mentioning

confidence: 93%

Section: Experimental Validation Of a Bearing Wear Model 2403mentioning

confidence: 99%

Section: Experimental Validation Of a Bearing Wear Model 2403mentioning

confidence: 99%

“…The wear model, proposed by Machado and Cavalca (2015) and used in this paper, is briefly presented here. A schematic worn bearing is shown in Figure 5.…”

Section: Wear Modelmentioning

confidence: 99%

Section: Wear Modelmentioning

confidence: 99%

See 3 more Smart Citations

Experimental validation of a bearing wear model using the directional response of the rotor-bearing system

Machado

2016

An. Acad. Bras. Ciênc.

Self Cite

Experimental validation and comparison between different active control methods applied to a journal bearing supported rotor

Struct Control Health Monit

2019

Summary Rotors supported by cylindrical hydrodynamic journal bearings usually face rotational speed limitations due to the unstable motion caused by oil whip effect. An active magnetic bearing is utilized as auxiliary component to suppress oil whip and reduce unbalance lateral vibration amplitude at critical speed. Three distinct control methods are considered for the actuation force (dynamic H∞, μ synthesis, and polynomially parameter‐dependent static H∞), which must be designed to perform in a situation with varying parameters and uncertainties. These techniques are tested in scenarios with collocated and noncollocated feedback (emulating a magnetic actuator with magnetic flux sensors). The different resultant performances are successfully compared with each other numerically and experimentally.

Feedforward Rotor Fault Compensation

Struct Control Health Monit

Markert

2020

Self Cite

When damaged, it is not unusual to observe nonlinear responses in previously linear structures. Specifically, in rotating machinery context, unbalance, misalignment, bearing, and shaft damage occur during operation, and their responses arise as a combination of multiple modes and harmonics. These vibration effects are undesirable and, besides compromising the system performance, can propagate or generate further faults. In practice, the machine cannot be simply stopped for repairs, and a method for provisory attenuating such problems is desirable. The fault effects can be approximated by a set of loads distributed along the healthy rotor linear model approximation. Intuitively, one can also estimate counteractive forces to mitigate the fault symptoms. Therefore, this work proposes a simple feedforward approach to detect and compensate fault effects at multiple harmonics in rotors. The compensating force is calculated to minimize the least square modal difference between healthy and faulty rotor. A test rig is operated in distinct conditions to demonstrate and validate the method highlighting different fault symptoms (unbalance, misalignment, and shaft bow).