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Author: National Aeronautics and Space Administration (NASA) Publisher: Createspace Independent Publishing Platform ISBN: 9781722184537 Category : Languages : en Pages : 24
Book Description
A finite-element model of a geared rotor system on flexible bearings was developed. The model includes the rotary inertia of shaft elements, the axial loading on shafts, flexibility and damping of bearings, material damping of shafts and the stiffness and the damping of gear mesh. The coupling between the torsional and transverse vibrations of gears were considered in the model. A constant mesh stiffness was assumed. The analysis procedure can be used for forced vibration analysis of geared rotors by calculating the critical speeds and determining the response of any point on the shaft to mass unbalances, geometric eccentricities of gears and displacement transmission error excitation at the mesh point. The dynamic mesh forces due to these excitations can also be calculated. The model has been applied to several systems for the demonstration of its accuracy and for studying the effect of bearing compliances on system dynamics. Kahraman, Ahmet and Ozguven, H. Nevzat and Houser, Donald R. and Zakrajsek, James J. Glenn Research Center NAG3-773; DA PROJ. 1L1-62209-A4-7A; RTOP 505-63-51...
Author: National Aeronautics and Space Administration (NASA) Publisher: Createspace Independent Publishing Platform ISBN: 9781722184537 Category : Languages : en Pages : 24
Book Description
A finite-element model of a geared rotor system on flexible bearings was developed. The model includes the rotary inertia of shaft elements, the axial loading on shafts, flexibility and damping of bearings, material damping of shafts and the stiffness and the damping of gear mesh. The coupling between the torsional and transverse vibrations of gears were considered in the model. A constant mesh stiffness was assumed. The analysis procedure can be used for forced vibration analysis of geared rotors by calculating the critical speeds and determining the response of any point on the shaft to mass unbalances, geometric eccentricities of gears and displacement transmission error excitation at the mesh point. The dynamic mesh forces due to these excitations can also be calculated. The model has been applied to several systems for the demonstration of its accuracy and for studying the effect of bearing compliances on system dynamics. Kahraman, Ahmet and Ozguven, H. Nevzat and Houser, Donald R. and Zakrajsek, James J. Glenn Research Center NAG3-773; DA PROJ. 1L1-62209-A4-7A; RTOP 505-63-51...
Author: Rajendra Singh Publisher: DIANE Publishing ISBN: 1428915540 Category : Bearings Languages : en Pages : 236
Book Description
A new mathematical model is proposed to examine the vibration transmission through rolling element bearings in geared rotor systems. Current bearing models, based on either ideal boundary conditions for the shaft or purely translational stiffness element description, cannot explain how the vibratory motion may be transmitted from the rotating shaft to the casing. For example, a vibration model based upon the simple bearing formulations can only predict purely in-plane type motion on the flexible casing plate given only bending motion on the shaft. However, experimental results have shown that the casing plate motion is primarily flexural. This study clarifies this issue qualitatively and quantitatively by developing a comprehensive bearing stiffness matrix is partially verified using available analytical and experimental data, and is completely characterized. This study extends the proposed bearing formulation to analyze the overall geared rotor system dynamics including casting and mounts. The bearing stiffness matrix is included in discrete system models using lumped parameter and/or dynamic finite element techniques. Eigensolution and forced harmonic response due to rotating mass unbalance or kinematic transmissions error excitation for the following examples are computed: (I) single-stage rotor system with flexible shaft supported by two bearings on rigid casing and flexible mounts, (II) spur gear pair system with motor and load inertials attached to two flexible shafts and supported by four bearings on flexibly mounted rigid casing, and (III) case II with flexible casing and rigid mounts. In several of these examples, analytical predictions compare well with measured data, validating the purposed formulation.
Author: Arne Vollan Publisher: CRC Press ISBN: 143984772X Category : Science Languages : en Pages : 296
Book Description
For more than a century, we have had a firm grasp on rotor dynamics involving rigid bodies with regular shapes, such as cylinders and shafts. However, to achieve an equally solid understanding of the rotational behavior of flexible bodies-especially those with irregular shapes, such as propeller and turbine blades-we require more modern tools and m
Author: Andrew D. Dimarogonas Publisher: Springer Science & Business Media ISBN: 9400759053 Category : Technology & Engineering Languages : en Pages : 280
Book Description
The design and construction of rotating machinery operating at supercritical speeds was, in the 1920s, an event of revolutionary importance for the then new branch of dynamics known as rotor dynamics. In the 1960s, another revolution occurred: In less than a decade, imposed by operational and economic needs, an increase in the power of turbomachinery by one order of magnitude took place. Dynamic analysis of complex rotor forms became a necessity, while the importance of approximate methods for dynamic analysis was stressed. Finally, the emergence of fracture mechanics, as a new branch of applied mechanics, provided analytical tools to investigate crack influence on the dynamic behavior of rotors. The scope of this book is based on all these developments. No topics related to the well-known classical problems are included, rather the book deals exclusively with modern high-power turbomachinery.
Author: Rajiv Tiwari Publisher: CRC Press ISBN: 1351863630 Category : Science Languages : en Pages : 1225
Book Description
The purpose of this book is to give a basic understanding of rotor dynamics phenomena with the help of simple rotor models and subsequently, the modern analysis methods for real life rotor systems. This background will be helpful in the identification of rotor-bearing system parameters and its use in futuristic model-based condition monitoring and, fault diagnostics and prognostics. The book starts with introductory material for finite element methods and moves to linear and non-linear vibrations, continuous systems, vibration measurement techniques, signal processing and error analysis, general identification techniques in engineering systems, and MATLAB analysis of simple rotors. Key Features: • Covers both transfer matrix methods (TMM) and finite element methods (FEM) • Discusses transverse and torsional vibrations • Includes worked examples with simplicity of mathematical background and a modern numerical method approach • Explores the concepts of instability analysis and dynamic balancing • Provides a basic understanding of rotor dynamics phenomena with the help of simple rotor models including modern analysis methods for real life rotor systems.
Author: Chong-Won Lee Publisher: Springer Science & Business Media ISBN: 9401581738 Category : Technology & Engineering Languages : en Pages : 324
Book Description
This text is intended for use as an advanced course in either rotordynamics or vibration at the graduate level. This text has mostly grown out of the research work in my laboratory and the lectures given to graduate students in the Mechanical Engineering Department, KAIST. The text contains a variety of topics not normally found in rotordynamics or vibration textbooks. The text emphasizes the analytical aspects and is thus quite different from conventional rotordynamics texts; potential readers are expected to have a firm background in elementary rotordynamics and vibration. In most previously published rotordynamics texts, the behavior of simple rotors has been of a primary concern, while more realistic, multi-degree-f-freedom or continuous systems are seldom treated in a rigorous way, mostly due to the difficulty of a mathematical treatment of such complicated systems. When one wanted to gain a deep insight into dynamic phenomena of complicated rotor systems, one has, in the past, either had to rely on computational techniques, such as the transfer matrix and finite element methods, or cautiously to extend ideas learned from simple rotors whose analytical solutions are readily available. The former methods are limited in the interpretation of results, since the calculations relate only to the simulated case, not to more general system behavior. Ideas learned from simple rotors can, fortunately, often be extended to many practical rotor systems, but there is of course no guarantee of their validity.
Author: J. S. Rao Publisher: New Age International ISBN: 9788122409772 Category : Rotors Languages : en Pages : 460
Book Description
The Third Revised And Enlarged Edition Of The Book Presents An In-Depth Study Of The Dynamic Behaviour Of Rotating And Reciprocating Machinery. It Evolved Out Of Lectures Delivered At Different Universities Over The Last Two Decades. The Book Deals With Torsional And Bending Vibrations Of Rotors, Stability Aspects, Balancing And Condition Monitoring. Closed Form Solutions Are Given Wherever Possible And Parametric Studies Presented To Give A Clear Understanding Of The Subject. Transfer Matrix Methods Is Extensively Used For General Class Of Rotors For Both Bending And Torsional Vibrations.Special Attentions Are Given To Transient Analysis Of The Rotors Which Is Becoming An Essential Part Of The Design Of High Speed Machinery. Systems With Fluid Film Bearings, Cracked Rotors And Two Spool Rotors Are Also Presented.A First Course On Theory Of Vibration Is A Prerequisite To This Study. Analysis Used Is Fairly Simple, But Sufficiently Advanced To The Requisite Level Of Predicting Practical Observations. As Far As Possible, Practical Examples Are Illustrated, So That The Book Is Also Useful To Practising Engineers.A Special Feature Of This Book Is Diagnostics Of Rotating Machinery Using Vibration Signature Analysis And Application Of Expert Systems To A Field Engineer In Trouble Shooting Work.
Author: National Aeronautics and Space Administration (NASA)
Author: National Aeronautics and Space Administration (NASA)
Author: 
Author: John Junyao Yu
Author: Rajendra Singh
Author: 
Author: Arne Vollan
Author: Andrew D. Dimarogonas
Author: Rajiv Tiwari
Author: Chong-Won Lee
Author: J. S. Rao