Analysis on Multimode Nonlinear Resonance of an Asymmetric Rolling Bearing Rotor with the Application of a Squeeze Film Damper

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.

Download Full-text

Nonlinear vibration response of a complex aeroengine under the rubbing fault

10.21203/rs.3.rs-242862/v1 ◽

2021 ◽

Author(s):

Jingze Liu ◽

Qingguo Fei ◽

Shaoqing Wu ◽

Zhenhuan Tang ◽

Dahai Zhang

Keyword(s):

Nonlinear Vibration ◽

Dynamic Model ◽

Linear Part ◽

Rolling Bearing ◽

Squeeze Film ◽

Speed Ratio ◽

Squeeze Film Damper ◽

Structural Nonlinearity ◽

Varying Compliance ◽

Nonlinear Support

Abstract Rolling bearing and squeeze film damper will introduce structural nonlinearity into the dynamic model of aeroengine. Rubbing will occur due to the clearance reduction design of the engine. The coupling of structural nonlinearity and fault nonlinearity will make the engine present rich vibration responses. This paper aims to analyze the nonlinear vibration behavior of the whole aeroengine including rolling bearing and squeeze film damper under rubbing fault. Firstly, the dynamic model of a turboshaft engine with nonlinear support and rubbing fault is established; The rolling bearing force, the oil film force and the rubbing force are introduced into a dual-rotor-casing model with six support points. Secondly, the linear part of the model is verified by the dynamic characteristics of the three-dimensional finite element model. Finally, the varying compliance vibration, the damping effect and the bifurcation mechanism are analyzed in detail in which the bearing clearance, speed ratio and rubbing stiffness are considered. Results show that the rubbing fault in the nonlinear support case will excite more significant varying compliance vibration in the low-speed region and expand the rotating speed range of the chaotic region in the high-speed region compared with that in the linear support case.

Download Full-text

Analysis on multi-mode nonlinear resonance and jump behavior of an asymmetric rolling bearing rotor

Archive of Applied Mechanics ◽

10.1007/s00419-021-01944-y ◽

2021 ◽

Author(s):

Chen Huizheng ◽

Zhong Shun ◽

Lu Zhenyong ◽

Chen Yushu ◽

Han Jiajie ◽

...

Keyword(s):

Nonlinear Resonance ◽

Rolling Bearing ◽

Asymmetric Rolling ◽

Multi Mode

Download Full-text

Study on Vibration and Bifurcation of an Aeroengine Rotor System with Elastic Ring Squeeze Film Damper

Shock and Vibration ◽

10.1155/2021/4651339 ◽

2021 ◽

Vol 2021 ◽

pp. 1-15

Author(s):

Guoying Pang ◽

Shuqian Cao ◽

Yushu Chen ◽

Huizheng Chen

Keyword(s):

Structural Parameters ◽

Elastohydrodynamic Lubrication ◽

Rolling Bearing ◽

Rotor System ◽

Squeeze Film ◽

Force Model ◽

Elastic Ring ◽

Elastic Supports ◽

Oil Film ◽

Squeeze Film Damper

To analyze the problem of vibration and bifurcation in the rotor system of the aeroengine with the elastic ring squeeze film damper (ERSFD) and elastic supports, the theoretical equation of the dynamic rotor system is developed in this paper, based on the rotor system, elastic ring squeeze film damper (ERSFD), and three elastic supports. The estimated analytical solution of the oil film force is solved using the short bearing approximation theory and the semi-oil film inference theory in the suspension and the inner and outer boss contact. Considering the oil film stiffness and damping of rolling bearings, the rolling bearing force model is established based on the elastohydrodynamic lubrication (EHL) theory. By the average method, the vibration and bifurcation modes are obtained concerning the bearing coefficient and parameters. The range optimization of parameters can be appropriately improved to enhance the dynamic characteristics of the device given different parameters of the hole of oil seepage, the stiffness, the position of elastic supports, and other structural parameters.

Download Full-text

Ball bearing turbocharger vibration management: application on high speed balancer

Mechanics & Industry ◽

10.1051/meca/2020091 ◽

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.

Download Full-text

Influence of Eccentricity and Angular Velocity on Force Effects on Rotor of Magnetorheological Damper

EPJ Web of Conferences ◽

10.1051/epjconf/201818002091 ◽

2018 ◽

Vol 180 ◽

pp. 02091

Author(s):

Dominik Šedivý ◽

Petr Ferfecki ◽

Simona Fialová

Keyword(s):

Magnetic Induction ◽

Magnetorheological Damper ◽

Squeeze Film ◽

Fluid Viscosity ◽

Squeeze Film Damper ◽

Viscous Forces ◽

Angular Velocities ◽

Volume Method ◽

Gap Width ◽

Made In

This article presents the evaluation of force effects on squeeze film damper rotor. The rotor is placed eccentrically and its motion is translate-circular. The amplitude of rotor motion is smaller than its initial eccentricity. The force effects are calculated from pressure and viscous forces which were measured by using computational modeling. Damper was filled with magnetorheological fluid. Viscosity of this non-Newtonian fluid is given using Bingham rheology model. Yield stress is not constant and it is a function of magnetic induction which is described by many variables. The most important variables of magnetic induction are electric current and gap width between rotor and stator. The simulations were made in finite volume method based solver. The motion of the inner ring of squeeze film damper was carried out by dynamic mesh. Numerical solution was solved for five different initial eccentricities and angular velocities of rotor motion.

Download Full-text

Numerical investigation of dynamic and hydrodynamic characteristics of the pad in the fluid pivot journal bearing

Proceedings of the Institution of Mechanical Engineers Part J Journal of Engineering Tribology ◽

10.1177/13506501211033045 ◽

2021 ◽

pp. 135065012110330

Author(s):

Tuyen Vu Nguyen ◽

Weiguang Li

Keyword(s):

Computational Models ◽

Journal Bearing ◽

Squeeze Film ◽

Hydrodynamic Characteristics ◽

Hydrodynamic Properties ◽

Squeeze Film Damper ◽

Lubricant Oil ◽

Oil Flow ◽

Flow Through ◽

Bearing System

The dynamic and hydrodynamic properties of the pad in the fluid pivot journal bearing are investigated in this paper. Preload coefficients, recess area, and size gap, which were selected as input parameters to investigate, are important parameters of fluid pivot journal bearing. The pad’s pendulum angle, lubricant oil flow through the gap, and recess pressure which characterizes the squeeze film damper were investigated with different preload coefficients, recess area, and gap sizes. The computational models were established and numerical methods were used to determine the equilibrium position of the shaft-bearing system. Since then, the pendulum angle of the pad, liquid flow, and recess pressure were determined by different eccentricities.

Download Full-text

Dynamic Performance of a Squeeze Film Damper with a Cylindrical Roller Bearing under a Large Static Radial Loading Range

Machines ◽

10.3390/machines7010014 ◽

2019 ◽

Vol 7 (1) ◽

pp. 14 ◽

Cited By ~ 2

Author(s):

Hans Meeus ◽

Jakob Fiszer ◽

Gabriël Van De Velde ◽

Björn Verrelst ◽

Wim Desmet ◽

...

Keyword(s):

Roller Bearing ◽

Squeeze Film ◽

Stable Operation ◽

Large Power ◽

Squeeze Film Damper ◽

Depth Analysis ◽

Rotor Support ◽

Cylindrical Roller Bearing ◽

Radial Loading ◽

Cylindrical Roller

Turbomachine rotors, supported by little damped rolling element bearings, are generally sensitive to unbalance excitation. Accordingly, most machines incorporate squeeze film damper technology to dissipate mechanical energy caused by rotor vibrations and to ensure stable operation. When developing a novel geared turbomachine able to cover a large power range, a uniform mechanical drivetrain needs to perform well over the large operational loading range. Especially, the rotor support, containing a squeeze film damper and cylindrical roller bearing in series, is of vital importance in this respect. Thus, the direct objective of this research project was to map the performance of the envisioned rotor support by estimating the damping ratio based on the simulated and measured vibration response during run-up. An academic test rig was developed to provide an in-depth analysis on the key components in a more controlled setting. Both the numerical simulation and measurement results exposed severe vibration problems for an insufficiently radial loaded bearing due to a pronounced anisotropic bearing stiffness. As a result, a split first whirl mode arose with its backward component heavily triggered by the synchronous unbalance excitation. Hence, the proposed SFD does not function properly in the lower radial loading range. Increasing the static load on the bearing or providing a modified rotor support for the lower power variants will help mitigating the vibration issues.

Download Full-text