Experimental evaluation of damping coefficient of a squeeze film mounted ball bearing

1979 ◽  
Author(s):  
V. KUMAR ◽  
P. PARANJPE
Keyword(s):  
Experimental Evaluation ◽  
Ball Bearing ◽  
Damping Coefficient ◽  
Squeeze Film ◽  
Evaluation Of Damping

Ball bearing turbocharger vibration management: application on high speed balancer

2020 ◽  
Vol 21 (6) ◽  
pp. 619
Author(s):  
Kostandin Gjika ◽  
Antoine Costeux ◽  
Gerry LaRue ◽  
John Wilson
Keyword(s):  
Dynamic Behavior ◽  
High Speed ◽  
Internal Combustion Engines ◽  
Ball Bearing ◽  
Squeeze Film ◽  
Design And Technology ◽  
Squeeze Film Damper ◽  
Damping Coefficients ◽  
Bearing Loads ◽  
Stiffness And Damping

Today's modern internal combustion engines are increasingly focused on downsizing, high fuel efficiency and low emissions, which requires appropriate design and technology of turbocharger bearing systems. Automotive turbochargers operate faster and with strong engine excitation; vibration management is becoming a challenge and manufacturers are increasingly focusing on the design of low vibration and high-performance balancing technology. This paper discusses the synchronous vibration management of the ball bearing cartridge turbocharger on high-speed balancer and it is a continuation of papers [1–3]. In a first step, the synchronous rotordynamics behavior is identified. A prediction code is developed to calculate the static and dynamic performance of “ball bearing cartridge-squeeze film damper”. The dynamic behavior of balls is modeled by a spring with stiffness calculated from Tedric Harris formulas and the damping is considered null. The squeeze film damper model is derived from the Osborne Reynolds equation for incompressible and synchronous fluid loading; the stiffness and damping coefficients are calculated assuming that the bearing is infinitely short, and the oil film pressure is modeled as a cavitated π film model. The stiffness and damping coefficients are integrated on a rotordynamics code and the bearing loads are calculated by converging with the bearing eccentricity ratio. In a second step, a finite element structural dynamics model is built for the system “turbocharger housing-high speed balancer fixture” and validated by experimental frequency response functions. In the last step, the rotating dynamic bearing loads on the squeeze film damper are coupled with transfer functions and the vibration on the housings is predicted. The vibration response under single and multi-plane unbalances correlates very well with test data from turbocharger unbalance masters. The prediction model allows a thorough understanding of ball bearing turbocharger vibration on a high speed balancer, thus optimizing the dynamic behavior of the “turbocharger-high speed balancer” structural system for better rotordynamics performance identification and selection of the appropriate balancing process at the development stage of the turbocharger.

Damping Analysis of Asymmetrical Comb Accelerometer

2007 ◽  
Vol 353-358 ◽  
pp. 2597-2600 ◽  
Author(s):  
Wei Ping Chen ◽  
Zhen Gang Zhao ◽  
Xiao Wei Liu ◽  
Yu Min Lin
Keyword(s):  
Damping Ratio ◽  
Resonance Phenomenon ◽  
Damping Coefficient ◽  
Anodic Bonding ◽  
Squeeze Film ◽  
Frequency Bandwidth ◽  
Vibration Method ◽  
Capacitive Accelerometer ◽  
Squeeze Film Damping

The resonance phenomenon is suppressed by adjusting the damping of the comb accelerometer structure to widen the frequency bandwidth of the capacitive accelerometer. The capacitive accelerometer with asymmetrical combs, fabricated with DRIE and anodic bonding, is presented. The damping category of the accelerometer is introduced, in which the squeeze-film damping coefficient and the damping ratio factor are detailed. The damping ratio factor of the accelerometer, measured by a vibration method, is 0.17. The damping ratio factor of the optimized structure is calculated of 0.15 to 0.18 with the change of experiential modulus C from 25 to 30, theoretically.

scholarly journals Experimental Evaluation of Squeeze Film Supported Flexible Rotors

1982 ◽  
Author(s):  
M. D. Rabinowitz ◽  
E. J. Hahn
Keyword(s):  
Theoretical Model ◽  
Experimental Evaluation ◽  
Measurement Errors ◽  
Vibration Amplitude ◽  
Squeeze Film ◽  
Experimental Investigations ◽  
Flexible Rotors ◽  
The Mean ◽  
Lubricant Viscosity ◽  
Theory And Experiment

This paper describes the experimental investigations which were conducted to verify existing theoretical vibration amplitude predictions for centrally preloaded, squeeze film supported flexible rotors. The influence of measurement errors and operating condition uncertainties are quantified. The agreement between theory and experiment was excellent, and it is shown that any discrepancy can be explained in terms of errors in determining the mean lubricant viscosity and the orbit magnitudes. Hence, for the range of parameters investigated, the theoretical model and predictions therefrom are validated.

Experimental Evaluation of Ball Bearing Performance Using Nanoflake-Blended Greases

2020 ◽  
Vol 49 (5) ◽  
pp. 20190727
Author(s):  
V. Bhardwaj ◽  
R. K. Pandey ◽  
V. K. Agarwal
Keyword(s):  
Experimental Evaluation ◽  
Ball Bearing

Experimental Evaluation of Dynamic Characteristics of Circular Arc Spring Dampers for Rotating Machinery

2020 ◽  
Author(s):  
Ryota Takeuchi ◽  
Hidetsugu Ishimaru ◽  
Hideaki Yamashita ◽  
Shota Yabui ◽  
Tsuyoshi Inoue
Keyword(s):  
Dynamic Characteristics ◽  
Experimental Evaluation ◽  
Mass Effect ◽  
Added Mass ◽  
Rotating Machinery ◽  
Squeeze Film ◽  
Outer Diameter ◽  
Circular Arc ◽  
Dynamic Coefficients ◽  
New Findings

Abstract This study presents an experimental evaluation of the dynamic characteristics of the circular arc spring damper (CASD), which attenuates the vibration of rotating machinery. A major advantage of CASDs over conventional Squeeze Film Dampers (SFDs) with squirrel-cage springs is their compactness and low weight. However, the basic characteristics of this type of damper, including the influence of the geometries, added mass coefficients, and cross-coupled terms of dynamic coefficients have not been investigated. To clarify these characteristics, a series of excitation tests was conducted on three types of CASDs to identify their dynamic coefficients. Tested dampers have the same outer diameter and damper width but different arc patterns and radial clearances. All dampers were tested in both open-end and end-sealed configuration. The influence of the end-seal clearances was also examined. The following results were obtained: (1) 4-arc type CASDs have greater damping than that of 2-arc types; (2) CASDs have a considerable amount of added mass coefficients, especially in the end-sealed condition; (3) Smaller end-seal clearances make the damping and added-mass coefficients significantly larger; (4) A large level of damping can be produced with dashpot configuration (large radial clearances and small end-seal clearances), though the added-mass effect becomes more prominent; (5) Cross-coupled terms are very small in centered / small amplitude motion. These new findings can be utilized for the design and application of CASDs to real rotating machineries.

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