scholarly journals Experimental Measurements of Actively Controlled Bearing Damping With an Electrorheological Fluid

1999 ◽  
Author(s):  
John M. Vance ◽  
Daniel Ying
Keyword(s):  
Active Control ◽  
Electrical Power ◽  
Companion Paper ◽  
Squeeze Film ◽  
Control Logic ◽  
Response Curves ◽  
Rotor Bearing ◽  
Er Damper ◽  
Er Fluid ◽  
Bearing System

Selection criteria and design evaluations of several types of bearing dampers with active control for application to aircraft engines were described in a companion paper (Vance, Ying, and Nikolajsen, 1999). A disk type electrorheological (ER) damper was chosen for further study and testing. The results of the tests and the final conclusions of the study are described in this paper. Experimental results including stiffness and damping coefficients are presented for the ER bearing damper with two types of ER fluid, 350 CS and 10 CS (centistokes) viscosity. The vibration attenuation performance of the ER damper was measured on a rotordynamic test rig in the form of free vibration decay, rotor orbits, and runup unbalance responses. The results show that the ER fluid with lower viscosity has the better characteristics for rotordynamic applications. It was found that ER fluids produce both Coulomb and viscous damping. If only the damping is considered, the Coulomb type is less desirable, but with active control it can also achieve control of rotor stiffness as analyzed in Vance and San Andres (1999). A feedback control system was developed and applied to the ER damper with the objective of improving the overall rotordynamic performance of the rotor bearing system, considering both vibration amplitudes and dynamic bearing forces. A “bang-bang” (on and off) simple control logic was found to work better in practice than more sophisticated schemes. The measured runup responses of the rotor-bearing system with this control approximated the desired vibration response curves fairly well. The tests highlighted some of the practical considerations that would be important for aircraft engine applications, such as the ER fluid limitations, the electrical power supply requirements, the electrical insulation requirements, the nonlinear relationship between the voltage and the damping, and the relative benefits of active control. It is concluded that active control of bearing damping is probably not a practical improvement over the passive squeeze film dampers currently used in most aircraft gas turbine engines.

Experimental Measurements of Actively Controlled Bearing Damping With an Electrorheological Fluid

2000 ◽  
Vol 122 (2) ◽  
pp. 337-344 ◽  
Author(s):  
John M. Vance ◽  
Daniel Ying
Keyword(s):  
Active Control ◽  
Electrical Power ◽  
Companion Paper ◽  
Squeeze Film ◽  
Control Logic ◽  
Response Curves ◽  
Rotor Bearing ◽  
Er Damper ◽  
Er Fluid ◽  
Bearing System

Selection criteria and design evaluations of several types of bearing dampers with active control for application to aircraft engines were described in a companion paper. A disk type electrorheological (ER) damper was chosen for further study and testing. The results of the tests and the final conclusions of the study are described in this paper. Experimental results including stiffness and damping coefficients are presented for the ER bearing damper with two types of ER fluid, 350 CS and 10 CS (centistokes) viscosity. The vibration attenuation performance of the ER damper was measured on a rotordynamic test rig in the form of free vibration decay, rotor orbits, and runup unbalance responses. The results show that the ER fluid with lower viscosity has the better characteristics for rotordynamic applications. It was found that ER fluids produce both Coulomb and viscous damping. If only the damping is considered, the Coulomb type is less desirable, but with active control it can also achieve control of rotor stiffness. A feedback control system was developed and applied to the ER damper with the objective of improving the overall rotordynamic performance of the rotor bearing system, considering both vibration amplitudes and dynamic bearing forces. A “bang–bang” (on and off) simple control logic was found to work better in practice than more sophisticated schemes. The measured runup response of the rotor-bearing system with this control approximated the desired vibration response curves fairly well. The tests highlighted some of the practical considerations that would be important for aircraft engine applications, such as the ER fluid limitations, the electrical power supply requirements, the electrical insulation requirements, the nonlinear relationship between the voltage and the damping, and the relative benefits of active control. It is concluded that active control of bearing damping is probably not a practical improvement over the passive squeeze film dampers currently used in most aircraft gas turbine engines. [S0742-4795(00)01202-3]

scholarly journals Analytical and Experimental Investigation of the Stability of the Rotor-Bearing System of a New Small Turbocharger

1987 ◽  
Author(s):  
H. R. Born
Keyword(s):  
Experimental Investigation ◽  
Dynamic Stability ◽  
Squeeze Film ◽  
Test Results ◽  
Flow Capacity ◽  
Squeeze Film Dampers ◽  
Rotor Bearing ◽  
The Stability ◽  
Turbine Design ◽  
Bearing System

This paper presents an overview of the development of a reliable bearing system for a new line of small turbochargers where the bearing system has to be compatible with a new compressor and turbine design. The first part demonstrates how the increased weight of the turbine, due to a 40 % increase in flow capacity, influences the dynamic stability of the rotor-bearing system. The second part shows how stability can be improved by optimizing important floating ring parameters and by applying different bearing designs, such as profiled bore bearings supported on squeeze film dampers. Test results and stability analyses are included as well as the criteria which led to the decision to choose a squeeze film backed symmetrical 3-lobe bearing for this new turbocharger design.

Parameter Identification of a Strongly Nonlinear Rotor-Bearing System Based on Reconstructed Constant Response Tests

2020 ◽  
Vol 142 (8) ◽  
Author(s):  
Genbei Zhang ◽  
Chaoping Zang ◽  
Michael I. Friswell
Keyword(s):  
Test Method ◽  
Fixed Frequency ◽  
Multiple Responses ◽  
Response Curves ◽  
Frequency Test ◽  
Strongly Nonlinear ◽  
Jump Phenomena ◽  
Rotor Bearing ◽  
Nonlinear Support ◽  
Bearing System

Abstract A strongly nonlinear rotor-bearing system often has multiple solutions under harmonic excitations and jump phenomena. For example, a hardening nonlinearity may include a jump-down in the acceleration process and jump-up in the deceleration process. It is challenging to measure all of these multiple responses and establish an accurate dynamic model from experimental data to predict these phenomena. This paper used a fixed frequency test method to measure all of these multiple responses under harmonic excitations and developed a novel strategy to characterize and identify nonlinearities in a strongly nonlinear rotor-bearing system based on reconstructing constant response tests from fixed frequency test data. The fixed frequency tests are achieved by monotonically increasing the voltage applied to the exciter at a fixed frequency and using the force drop-out phenomenon through the resonance to control the force applied to the structure. This test method could measure multivalued response curves of a strongly nonlinear rotor-bearing system in a nonrotating state. The constant response tests could be reconstructed from these multivalued response curves. The relationship of equivalent stiffness versus displacement can be established, and hence, the nonlinear stiffness is characterized and identified from constant response tests. A rotor-bearing system with a strongly nonlinear support is used to demonstrate the method, and the nonlinear support stiffness parameters are identified and validated in a nonrotating state. The identified nonlinear rotor-bearing model also could predict the jump phenomena in the acceleration or deceleration process. The results demonstrate the feasibility and effectiveness of the approach, and also show the potential for practical applications in engineering.

Study of Transfer Matrix of Rolling Bearing Including Squeeze Film Damper

2012 ◽  
Vol 490-495 ◽  
pp. 618-622
Author(s):  
Hua Tao Tang ◽  
Xin Yue Wu
Keyword(s):  
Transfer Matrix ◽  
Transfer Matrix Method ◽  
Matrix Method ◽  
Rolling Bearing ◽  
Squeeze Film ◽  
Body System ◽  
Squeeze Film Damper ◽  
Rotor Bearing ◽  
Multi Body ◽  
Bearing System

The transfer matrix of rolling bearing including squeeze film damper (SFD) is studied, and the rotor – bearing system is modeled by transfer matrix method of multi-body system. It is proved by an example that the method, which provides a new idea to solve the problem of complex rotor – bearing system, is feasible and effective.

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