A Dynamic Analysis for Elastic Structures Interacting with Rotating Machinery

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.

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Modal method based dynamic analysis of cantilever type elastic structures

Optics and Precision Engineering ◽

10.3788/ope.20152308.2250 ◽

2015 ◽

Vol 23 (8) ◽

pp. 2250-2257

Author(s):

薛志鹏 XUE Zhi-peng ◽

厉明 LI Ming ◽

贾宏光 JIA Hong-guang ◽

罗泽勇 LUO Ze-yong

Keyword(s):

Dynamic Analysis ◽

Elastic Structures ◽

Modal Method

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Dynamic Analysis of Horizontal Rotating Machinery

10.4271/1999-01-3037 ◽

1999 ◽

Author(s):

Katia Lucchesi Cavalca ◽

Heron Quinsan Lins

Keyword(s):

Dynamic Analysis ◽

Rotating Machinery

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Structural Design and Dynamic Analysis of Carbon Fiber Reinforced Plastic Shaft with Metal Parts

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.861.193 ◽

2020 ◽

Vol 861 ◽

pp. 193-201

Author(s):

Wei Bo Yang ◽

Hua Chun Wu ◽

Jian Zhou ◽

Jin Guang Zhang

Keyword(s):

Dynamic Analysis ◽

Natural Frequency ◽

Dynamic Characteristics ◽

Structural Design ◽

Fiber Orientation ◽

Orientation Angle ◽

Fem Analysis ◽

Rotating Machinery ◽

Stacking Sequence ◽

Fiber Orientation Angle

It is important to improve dynamic performance of rotating machinery by reducing the mass of shaft and increasing the natural frequency. Many studies have focused on dynamic characteristics of shaft in rotating machinery with the utilization of composite material. This paper mainly investigates the structural design and dynamic analysis of a CFRP/Metal hybrid shaft. The finite element method (FEM) has been used to determine the selection of design variables include fiber orientation angle, layers stacking sequence and layers thickness. Also, experimental test was carried out using a FFT analyzer with impact hammers. The differences between the FEM analysis result and the experiment test result were respectively less than 4.5% and 6.3% for the first two natural frequencies; therefore, the results of FEM analysis are acceptable. The results reveal that the fiber orientation angle is the most significant factor affecting the dynamic characteristics of CFRP/Metal hybrid shaft. In addition, there have some effect of the layer stacking sequence on natural frequency.

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Alternative to traditional systems of vibration control of rotating machinery

Proceedings of the Institution of Mechanical Engineers Part E Journal of Process Mechanical Engineering ◽

10.1243/095440805x8557 ◽

2005 ◽

Vol 219 (1) ◽

pp. 27-42

Author(s):

R. D. Ambrosini ◽

R. O. Curadelli ◽

R. F. Danesi

Keyword(s):

Dynamic Analysis ◽

Vibration Control ◽

Control Systems ◽

Numerical Study ◽

Rotating Machinery ◽

Acceleration Response ◽

Support Structure ◽

Vibration Absorption ◽

Alternative Systems

The main objective of this paper is the comparison between the efficiency of vibration control systems of rotating machinery, in order to present alternatives for the cases in which it is not possible or convenient to use traditional systems. Moreover, the formulation of the theoretical dynamic load that should be used in the dynamic analysis is discussed. An experimental and numerical study is presented considering as an alternative system of vibration absorption the incorporation of masses on the support structure. Masses of 5, 10, and 15 per cent of the total mass of the vibrating machinery are included in the analysis. A set of tests about a case study on the spring (traditional) and built-in masses (alternative) systems is presented. Moreover, a linear dynamic analysis of the models with a finite element code was carried out. The behaviour of the built-in masses system is very good, reducing the acceleration response on the support structure to levels comparable to traditional systems.

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