scholarly journals Nonlinear Dynamic Behaviors of a Marine Rotor-Bearing System Coupled with Air Bag and Floating-Raft

2015 ◽  
Vol 2015 ◽  
pp. 1-18 ◽  
Author(s):  
W. Zhao ◽  
M. Li ◽  
L. Xiao
Keyword(s):  
Nonlinear Dynamic ◽  
Largest Lyapunov Exponent ◽  
Steady State Response ◽  
Dynamic Effects ◽  
State Response ◽  
Floating Raft ◽  
Rotor Bearing ◽  
Vibration Mechanism ◽  
Air Bag ◽  
Bearing System

To understand the nonlinear dynamic mechanism of a rotor-bearing system coupled with air bag and floating-raft, the dynamic characteristics of the system are investigated. This work has two key objectives. First, the vibration mechanism of rotor-bearing system coupled with air bag and floating-raft is investigated by developing a numerical model. Then, the nonlinear dynamics of the system and the effect of several parameters are studied, which includes the steady-state response and its spectrum, the orbit and its Poincaré map, the bifurcation diagram, and largest Lyapunov exponent (LLE). The results show that at low speed the dynamic behavior appears in a single periodic motion, and, with the increase of the speed, the motion becomes quasi-periodic and chaotic. These performances indicate that the air bag and floating-raft introduce some dynamic effects of marine rotor-bearing system.

Study of Nonlinear Dynamics of Rotor-Bearing System Coupled with a Floating Raft Isolation Device

2014 ◽  
Vol 598 ◽  
pp. 202-205 ◽  
Author(s):  
Wen Zhao ◽  
Ming Li
Keyword(s):  
Periodic Motion ◽  
Nonlinear Dynamic ◽  
Basic Assumption ◽  
Mathematic Model ◽  
State Response ◽  
Floating Raft ◽  
Nonlinear Dynamic Characteristics ◽  
Rotor Bearing ◽  
Isolation Device ◽  
Bearing System

The mathematic model of rotor-bearing system coupled with floating raft isolation device is developed and its nonlinear dynamic characteristics are mainly discussed in this paper. First, on the basic assumption theory of short bearing, the nonlinear dynamic motions of the system with 4 DOF is deduced after considering the vertical and horizontal deformation and the nonlinear vibrating behaviors are analyzed such as the steady state response and its spectrum, orbit and its Poincaré map. The results show that the responses at a low speed appear single periodic motion, with increasing the speed it indicates the doubling and quasi periodic motion, etc.

Dynamic Response of a Geared Rotor-Bearing System Under Residual Shaft Bow Effect

2006 ◽  
Author(s):  
T. N. Shiau ◽  
E. K. Lee ◽  
Y. C. Chen ◽  
T. H. Young
Keyword(s):  
Steady State ◽  
Natural Frequencies ◽  
Coupling Effect ◽  
Equations Of Motion ◽  
Transmission Error ◽  
Mode Shapes ◽  
Steady State Response ◽  
State Response ◽  
Rotor Bearing ◽  
Bearing System

The paper presents the dynamic behaviors of a geared rotor-bearing system under the effects of the residual shaft bow, the gear eccentricity and excitation of gear’s transmission error. The coupling effect of lateral and torsional motions is considered in the dynamic analysis of the geared rotor-bearing system. The finite element method is used to model the system and Lagrangian approach is applied to derive the system equations of motion. The dynamic characteristics including system natural frequencies, mode shapes and steady-state response are investigated. The results show that the magnitude of the residual shaft bow, the phase angle between gear eccentricity and residual shaft bow will significantly affect system natural frequencies and steady-state response. When the spin speed closes to the second critical speed, the system steady state response will be dramatically increased by the residual shaft bow for the in-phase case. Moreover the zero response can be obtained when the system is set on special conditions.

Dynamic Analysis of a Geared Rotor-Bearing System With Viscoelastic Supports Under the Bow Effect

2007 ◽  
Author(s):  
T. N. Shiau ◽  
E. K. Lee ◽  
T. H. Young ◽  
W. C. Hsu
Keyword(s):  
Steady State ◽  
Dynamic Analysis ◽  
Loss Factor ◽  
Critical Speed ◽  
Transmission Error ◽  
Steady State Response ◽  
Critical Speeds ◽  
State Response ◽  
Rotor Bearing ◽  
Bearing System

This paper investigates the dynamic behaviors of a geared rotor-bearing system mounted on viscoelastic supports under considerations of the gear eccentricity, excitation of the gear’s transmission error and the residual shaft bow. The finite element method is used to model the system and Lagrangian approach is applied to derive the system equations of motion. The coupling effect of lateral and torsional motions is considered in the system dynamic analysis. The investigated dynamic characteristics include system natural frequencies and steady-state response. The results show that the mass, the stiffness and the loss factor of the viscoelastic support will significantly affect system critical speeds and steady-state response. Larger loss factor and more rigid stiffness of the viscoelastic supports will suppress the systematic amplitude of resonance. Parameters, which include magnitude of the residual bow and phase angle, are also considered in the investigation of their effects on system critical speeds and steady-state response. Results show that they have tremendous influence on first critical speed when the geared system mounted on stiff viscoelastic supports. The transmission error of the gear mesh is assumed to be sinusoidal with tooth passing frequency and it will induce multiple low resonant frequencies in the system response. It is observed that the excited critical speed equals to the original critical speed divided by gear tooth number.

Nonlinear Dynamic Behavior of a Rotor Bearing System With Nonlinear Viscous Damping Suspension

2017 ◽  
Author(s):  
Shuai Yan ◽  
Bin Lin ◽  
Jixiong Fei ◽  
Pengfei Liu
Keyword(s):  
Dynamic Behavior ◽  
Nonlinear Dynamic ◽  
Vibration Isolation ◽  
Lubricating Oil ◽  
Viscous Damping ◽  
Oil Viscosity ◽  
Speed Range ◽  
Rotor Bearing ◽  
Nonlinear Dynamic Behavior ◽  
Bearing System

Nonlinear damping suspension has gained attention owing to its excellent vibration isolation performance. In this paper, a cubic nonlinear viscous damping suspension was introduced to a rotor bearing system for vibration isolation between the bearing and environment. The nonlinear dynamic response of the rotor bearing system was investigated thoroughly. First, the nonlinear oil film force was solved based short bearing approximation and half Sommerfeld boundary condition. Then the motion equations of the system was built considering the cubic nonlinear viscous damping. A computational method was used to solve the equations of motion, and the bifurcation diagrams were used to display the motions. The influences of rotor-bearing system parameters were discussed from the results of numerical calculation, including the eccentricity, mass, stiffness, damping and lubricating oil viscosity. The results showed that: (1) medium eccentricity shows a wider stable speed range; (2) rotor damping has little effect to the stability of the system; (3) lower mass ratio produces a stable response; (4) medium suspension/journal stiffness ratio contributes to a wider stable speed range; (5) a higher viscosity shows a wider stable speed range than lower viscosity. From the above results, the rotor bearing system shows complex nonlinear dynamic behavior with nonlinear viscous damping. These results will be helpful to carrying out the optimal design of the rotor bearing system.

An Investigation in Optimal Locations by Genetic Algorithm for Balancing Flexible Rotor-Bearing Systems

2005 ◽  
Author(s):  
Tsu-Wei Lin ◽  
Yuan Kang ◽  
Chun-Chieh Wang ◽  
Chuan-Wei Chang ◽  
Chih-Pin Chiang
Keyword(s):  
Genetic Algorithm ◽  
Finite Element Method ◽  
Steady State ◽  
Hermitian Matrix ◽  
Influence Coefficient ◽  
Steady State Response ◽  
Flexible Rotor ◽  
The Finite Element Method ◽  
State Response ◽  
Rotor Bearing

This study utilizes genetic algorithm to minimize the condition number of Hermitian matrix of influence coefficient (HMIC) to reduce the computation errors in balancing procedure. Then, the optimal locations of balancing planes and sensors would be obtained as fulfilling optimization. The finite element method is used to determine the steady-state response of flexible rotor-bearing systems. The optimization improves the balancing accuracy, which can be validated by the experiments of balancing a rotor kit.

Nonlinear dynamic analysis of cutting head-rotor-bearing system of the roadheader

2019 ◽  
Vol 33 (3) ◽  
pp. 1033-1043
Author(s):  
Zhilong Huang ◽  
Zhongchao Zhang ◽  
Yiming Li ◽  
Guiqiu Song ◽  
Yang He
Keyword(s):  
Dynamic Analysis ◽  
Nonlinear Dynamic ◽  
Nonlinear Dynamic Analysis ◽  
Cutting Head ◽  
Rotor Bearing ◽  
Bearing System

Dynamic Modeling and Vibration Analysis of the Drum Washing Machine Based on Four-Terminal Parameter Method

2012 ◽  
Vol 501 ◽  
pp. 179-184
Author(s):  
Jun Fei Wu ◽  
Hui Li ◽  
Xue Zheng Yang ◽  
Xu Ping Zhang
Keyword(s):  
Steady State ◽  
Dynamic Model ◽  
Parameter Method ◽  
Steady State Response ◽  
Dynamics Model ◽  
Washing Machine ◽  
Basic Principles ◽  
State Response ◽  
Theoretical Support ◽  
Vibration Mechanism

In this study, the drum washer’s dynamic model has been conducted using Four-terminal parameter method. Firstly, the basic principles and advantages of the four-terminal parameters has been explained, and we have analyzed the vibration mechanism of the drum washer. Secondly, the drum washer was simplified ,and we extracted its dynamic model. Thirdly, we solve each of its components by using the four-terminal parameter method,and according to the connection between the components, determine each component and the system’s four-terminal parameters .Then, deduce the system’s matrix equations,get the complex steady-state response and steady-state response under sinusoidal excitation of the system. Last, input the drum washer’s actual parameters ,we can see that four-terminal parameter method dynamics model is correct. In a word, it is easy to analyze the vibration of complex systems. This paper is designed to provide theoretical support for the design of the drum washer’s damping device.

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