Machinery Vibration and Rotordynamics

The book is a text/reference for rotating machinery vibrations and related topics such as bearings and seals with information suitable for both novices and experts. It contains fundamental physical phenomena, mathematical and computational aspects, practical hardware considerations and troubleshooting and instrumentation and measurement techniques. Case studies of vibration problems in several different types of machines are included as well as computer simulation models used in industry. With applicable theory supplying the tools for success, Machine Vibration and Rotordynamics is a must have for engineers and designers.

Dr. JOHN M. VANCE was professor of mechanical engineering at Texas A&M University, retiring in 2007. He received his PhD (1967) degree from The University of Texas at Austin. His book Rotordynamics of Turbomachinery (Wiley) has sold more than 3,000 copies and is used by turbomachinery engineers around the world. He is an inventor on several patents relating to rotating machinery and vibration reduction. His patented TAMSEAL has been retrofitted to solve vibration problems in a number of high-pressure industrial compressors. He is an ASME Fellow and a registered professional engineer in the state of Texas.

Dr. FOUAD Y. ZEIDAN is the President of KMC, Inc., and Bearings Plus, Inc., two companies specializing in the supply of high-performance bearings, flexible couplings, and seals. Dr. Zeidan holds nine U.S. patents for integral squeeze film dampers and high-performance journal and thrust bearings. He has published more than thirty technical papers and articles on various turbomachinery topics and has been lecturing at the Annual Machinery Vibrations and Rotordynamics short course since 1991. Dr. Zeidan holds a BS, MS, and PhD degrees in mechanical engineering from Texas A&M University.

BRIAN T. MURPHY, PhD, PE, is a senior research scientist with the Center for Electromechanics at The University of Texas at Austin. He is also president of RMA, Inc., which develops and markets the Xlrotor suite of rotordynamic analysis software used worldwide by industry and academia. Dr. Murphy is the creator of the polynomial transfer matrix method, which is the fastest known method of performing rotordynamic calculations. He has authored numerous technical papers on rotordynamics and machinery vibration, and is also caretaker of the Web site www.rotordynamics.org.

Dedication
Preface
Fundamentals of Machine Vibration and Classical Solutions
The Main Sources of Vibration in Machinery
The Single Degree of Freedom (SDOF) Model
Using Simple Models For Analysis And Diagnostics
Six Techniques for Solving Vibration Problems With Forced Excitation
Identify And Reduce The Excitation Source
Tune The Natural Frequency To A Value Further Away From The Frequency Of Excitation To Avoid Resonance
Isolate The Modal Mass From The Vibratory Excitation By Making The Modal Stiffness Very Low
Add Damping To The System
Add A Vibration Absorber
Stiffen The System
Some Examples with Forced Excitation
Illustrative Example #1
Illustrative Example #2:
Illustrative Example #3:
Illustrative Example #4:
Some Observations about Modeling
Unstable Vibration
References
Exercises - Chapter 1
Torsional Vibration
Torsional Vibration Indicators
Torsional and Lateral Vibration - The Key Differences
Objectives of Torsional Vibration Analysis
Simplified Models
Computer Models
Kinetic Energy expression:
Potential Energy
Torsional Vibration Measurement
Frenc's Comparison Experiments
Strain Gages
Carrier Signal Transducers
Frequency-Modulated Systems
Amplitude-Modulated Systems
Frequency Analysis and the Sideband System
Frenc's Test Procedure and Results
A Special Tape for Optical Transducers
Time Interval Measurement Systems
Tora's Method
Barrios/Darlow Method
References
Exercises
Introduction to Rotordynamics Analysis
Objectives Of Rotordynamics Analysis
The Spring-Mass Model
Synchronous And Nonsynchronous Whirl
Analysis Of The Jeffcott Rotor
Polar Coordinates
Cartesian Coordinates
Physical Significance of the Solutions
Three Ways to Reduce Synchronous Whirl Amplitudes
Some Damping Definitions
The "Gravity Critical"
Critical Speed Definitions
Effect Of Flexible (Soft) Supports
Rotordynamic Effects Of The Force Coefficients - A Summary
The Direct Coefficients
The Cross Coupled Coefficients
Rotordynamic Instability
Effect Of Cross-Coupled Stiffness On Unbalance Response
Added Complexities
Gyroscopic Effects
Effect Of Support Asymmetry On Synchronous Whirl
False Instabilities
Agreement of the sub-synchronous frequency with known eigenvalues of the system
Presence of higher harmonics or multiple frequencies
Orbit Shape - Ellipticity
Sub-synchronous frequency exactly one half of shaft speed
Sub-synchronous frequency equal to a torsional natural frequency
A change in the measured synchronous phase angle due to cross-coupled stiffness
References
Exercises
Computer Simulations of Rotordynamics
Different Types Of Models
Bearing & Seal Matrices
Torsional and Axial Models
Different Types Of Analyses
Eigenanalysis
Linear Forced Response (LFR)
Transient Response
Shaft Modeling Recommendations
How Many Elements
45 Degree Rule
Interference Fits
Laminations
Trunnions
Impeller Inertias via CAD Software
Stations for Added Weights
Rap Test Verification of Models
Stations for Bearings and Seals
Flexible Couplings
Example Simulations
Damped Natural Frequency Map (NDF)
Modal Damping Map
Root Locus Map
Undamped Critical Speed Map
Mode Shapes
Bode/Polar Response Plot
Orbit Response Plot
Bearing Load Response Plot
Operating Deflected Shape (ODS)
Housing Vibration (ips & 's)
List of References
Bearings and Their Effect on Rotordynamics
Fluid Film Bearings
Fixed Geometry Sleeve Bearings
Variable Geometry Tilting Pad Bearings
Fluid Film Bearing Dynamic Coefficients and Methods of Obtaining Them
Load Between Pivot (LBP) vs. Load on Pivot (LOP)
Influence of Preload on the Dynamic Coefficients in Tilt Pad Bearings
Influence of the Bearing Length or Pad Length
Influence of the Pivot Offset
Influence of the Number of Pads
Ball and Rolling Element Bearings
Case Study: Bearing Support Design for a Rocket Engine Turbopump
Ball Bearing Stiffness Measurements
Wire Mesh Damper Experiments and Computer Simulations
Squeeze Film Dampers
Squeeze Film Damper without a Centering Spring
O-Ring Supported Dampers
Squirrel Cage Supported Dampers
Integral Squeeze Film Dampers
Squeeze Film Damper Rotordynamic Force Coefficients
Applications of Squeeze Film Dampers
Optimization for Improving Stability in a Centrifugal Process Compressor
Using Dampers to Improve the Synchronous Response
Using the Damper to Shift a Critical Speed or a Resonance
Insights into the Rotor Bearing Dynamic Interaction with Soft/Stiff Bearing Supports
Influence on Natural Frequencies with Soft/Stiff Bearing Supports
Effects of Mass Distribution on the Critical Speeds with Soft/Stiff Bearing Supports
Influence of Overhung Mass on Natural Frequencies with Soft/Stiff Supports
Influence of Gyroscopic Moments on Natural Frequencies with Soft/Stiff bearing supports
Exercises
References
Fluid Seals and Their Effect on Rotordynamics
Function and Classification of Seals
Plain Smooth Seals
Floating Ring Seals
Conventional Gas Labyrinth Seals
Pocket Damper Seals
Honeycomb Seals
Hole Pattern Seals
Brush Seals
Understanding and Modeling Damper Seal Force Coefficients
Alfor's Hypothesis of Labyrinth Seal Damping
Cross-Coupled Stiffness Measurements
Invention of the Pocket Damper Seal
Pocket Damper Seal Theory
Rotordynamic Testing of Pocket Damper Seals
Impedance Measurements of Pocket Damper Seal Force Coefficients (Stiffness and Damping) and Leakage at Low Pressures
The Fully Partitioned PDS Design
Effects of Negative Stiffness
Frequency Dependence of Damper Seals
Laboratory Measurements of Stiffness and Damping from Pocket Damper Seals at High Pressures
The Conventional Design
The Fully Partitioned Design
Field Experience with Pocket Damper Seals
Designing for Desired Force Coefficient Characteristics
The Conventional PDS Design
The Fully Partitioned Pocket Damper Seal
Leakage Considerations
Some Comparisons of Different Types of Annular Gas Seals
Sources
References
History of Machinery Rotordynamics
The Foundation Years, 1869-1941
Summary
Shaft Dynamics
Bearings
Refining and Expanding The Rotordynamic Model, 1942-1963
Multi-Stage Compressors and Turbines, Rocket Engine Turbopumps, and Damper Seals, 1964 - Present
Stability Problems With Multi-Stage Centrifugal Compressors
Kaybob, 1971-72
Ekofisk, 1974-75
Subsequent Developments
New Frontiers of Speed and Power Density With Rocket Engine Turbopumps
The Space Shuttle Main Engine (SSME) High-Pressure Fuel Turbopump (HPFTP) Rotordynamic Instability Problem
Non-Contacting Damper Seals
List of references
Table of Contents provided by Publisher. All Rights Reserved.

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Machinery Vibration and Rotordynamics

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