Rotor Dynamic Analysis Using ANSYS

2010 ◽  
pp. 153-162 ◽  
Author(s):  
M. Santhosh Kumar
Keyword(s):  
Dynamic Analysis ◽  
Rotor Dynamic

An Evaluation of Mode Tracking Methods for Practical Rotor Dynamic Analysis

2020 ◽  
Author(s):  
Anurag Rajagopal ◽  
Dilip K. Mandal
Keyword(s):  
Dynamic Analysis ◽  
Rotating Machinery ◽  
Mode Shapes ◽  
Test Cases ◽  
Dynamic Simulations ◽  
Campbell Diagram ◽  
Practical Applications ◽  
Rotor Dynamic ◽  
Mode Tracking ◽  
Theoretical Foundations

Abstract An important precursor to the dynamic analysis of rotating machinery, in either frequency or time domain, is the extraction of its mode shapes and corresponding frequencies. This is often presented as a Campbell diagram, which plots the frequency of each mode as a function of the rotor speed. A typical Campbell diagram has several backward whirl, linear and forward whirl modes leading to numerous intersections. Therefore augmenting the eigenvalue solution with a mode tracking algorithm to output the Campbell diagram is of essential interest to a practicing engineer. This paper presents an evaluation of several mode tracking approaches for rotor dynamic simulations, starting from their theoretical foundations to practical applications using several test cases. These tracking algorithms are implemented in the structural solver, OptiStruct, part of Altair Engineering’s CAE framework. Finally, the conclusions drawn from this exercise offer engineers studying rotating machinery several key insights.

The Rotor Dynamic Analysis and Optimization in Turbocharger

2012 ◽  
Vol 226-228 ◽  
pp. 651-655 ◽  
Author(s):  
Na Na He ◽  
Hong Zhang
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Model ◽  
Critical Speed ◽  
Design Parameters ◽  
Optimization Strategy ◽  
Shaft Length ◽  
Rotor Structure ◽  
Rotor Dynamic ◽  
Computing Method ◽  
Bearing System

In this paper the rotor dynamic characters of the bearing system in turbocharger are researched. The computing method of rotor dynamic is also analyzed. Through modeling the components and parts of bearing system and rotor dynamic model, the three critical speeds are computed and analyzed. By comparing the working speed and critical speed, we can judge that whether the turbocharger works nearby the critical speed or not. If it does, then how to make the turbocharger work stably is also researched. At the same time, how the key design parameters, such as the shaft length and diameter, impact on rotor dynamic character is discussed in detail. In the end, an optimization strategy of the rotor structure is proposed to make the working speed be away from the critical speed.

Rotor Dynamic Modeling of Gears and Geared Systems

2013 ◽  
Author(s):  
Jason A. Kaplan ◽  
Saeid Dousti ◽  
Paul E. Allaire ◽  
Bradley R. Nichols ◽  
Timothy W. Dimond ◽  
...  
Keyword(s):  
Dynamic Analysis ◽  
High Speed ◽  
Degrees Of Freedom ◽  
Forced Response ◽  
Drive Train ◽  
Mode Shapes ◽  
Element Formulation ◽  
Resonant Frequencies ◽  
Industrial Drive ◽  
Rotor Dynamic

The ability to accurately predict rotating machine resonant frequencies and to assess their stability and response to external forces is crucial from a reliability and preventive maintenance perspective. Resonant frequencies and forced response become more difficult to predict when additional complicated components such as gearboxes are present in the rotor system. Gearbox dynamics contain many complex interactions and many of the simplifying assumptions provided in the literature do not apply to most geared systems. A finite element formulation of the gearbox, which couples the axial, lateral, and torsional degrees-of-freedom of the low and high-speed shafts, is developed. It has the capability to apply to a wide variety of both spur and helical geared systems and is sufficiently robust to account for arbitrary orientation angles between the parallel shafts. This study presents a rotor dynamic analysis of an industrial drive-train consisting of a steam turbine, herringbone gearbox, and a generator using 1-D Timoshenko beam elements. The rotor dynamic analysis consists of the calculation of the damped natural frequencies, mode shapes, and provides insight into the stability of the industrial drive-train.

scholarly journals Dynamic Analysis of Squeeze Film Damper Supported Rotors Using Equivalent Linearization

1993 ◽  
Author(s):  
A. El-Shafei ◽  
R. V. Eranki
Keyword(s):  
Dynamic Analysis ◽  
Numerical Integration ◽  
Dynamic Characteristics ◽  
Nonlinear Dynamic Analysis ◽  
Least Square ◽  
Squeeze Film ◽  
Equivalent Linearization ◽  
Squeeze Film Damper ◽  
Elliptic Orbits ◽  
Rotor Dynamic

The technique of equivalent linearization is presented in this paper as a powerful technique to perform nonlinear dynamic analysis of squeeze film damper (SFD) supported rotors using linear rotordynamic methods. Historically, it is customary to design squeeze film dampers (SFDs) for rotordynamic analysis by assuming circular centered orbits, which is convenient in making the nonlinear damper coefficients time independent and thus can be used in an iterative approach to determine the rotor dynamic characteristics. However, the general synchronous orbit is elliptic in nature due to possible asymmetry in the rotor support. This renders the nonlinear damper coefficients time dependent which would require extensive numerical computation using numerical integration to determine the rotor dynamic characteristics. Alternatively, it is shown that the equivalent linearization, which is based on a least square squares approach, can be used to obtain time independent damper coefficients for SFDs executing eccentric elliptic orbits which are nonlinear in the orbit parameters. The resulting equivalent linear forces are then used in an iterative procedure to obtain the unbalance response of a rigid rotor-SFD system. Huge savings over numerical integration are reported for this simple rotor. The technique can be extended to be used in conjunction with currently available linear rotordynamic programs to determine the rotor dynamic characteristics through iteration. It is expected that for multi-rotor multi-bearing systems this technique will result in even more economical computation.

scholarly journals Nonlinear Bearing Effects on Rotor Dynamic Analysis

1982 ◽  
Author(s):  
R. Colsher ◽  
I. Anwar ◽  
V. Obeid
Keyword(s):  
Dynamic Analysis ◽  
Degrees Of Freedom ◽  
Nonlinear Effects ◽  
Fluid Film ◽  
Response Analysis ◽  
Time Step ◽  
Tilting Pad ◽  
Rotor Support ◽  
Rotor Dynamic ◽  
Large Rotor

Nonlinear effects due to fluid film bearings become significant when vibratory amplitudes are large. To include these effects in rotor dynamic analysis requires conducting time-transient response analysis, where the fluid film forces are estimated at each time step. The present paper describes an approach where a unique treatment of bearing forces results in an efficient computational scheme for performing time transient analysis. The method developed is applicable to a flexible-rotor system with multi-degrees of freedom. A study conducted on a canned annulus motor pump using tilting pad bearings for the rotor support is described in this paper. The results showed severe loading at the bearings due to the canned annulus forces. Nonlinear effects due to the bearings were found only at large rotor unbalance loads.

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