Modelling Fault Detection And Active Vibration Control Of Rotor Dynamic Systems With Applications In Machine Tools
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Author | : Rajiv Kumar Vashisht |
Publisher | : |
Total Pages | : 0 |
Release | : 2020 |
Genre | : |
ISBN | : |
Rotors are extensively used to transfer energy from one part to other parts of a mechanical system. During the service life of the rotors, they are subjected to different faults like the rotor crack, coupling misalignment, rotor bow, rotor-stator rubbing and unbalance. One of the important aspects of these faults is their interconnection. Presence of one fault can accelerate the growth of the other. If these faults are not identified timely, costly breakdown of the rotor system can occur. The presence of these faults changes the overall nature of the system dynamics from the linear to nonlinear one. This aspect can be used to identify the presence of these faults. Various system components like ball bearings and journal bearings also make the overall dynamics of a healthy rotor system nonlinear. Hence, it is not easy to detect the presence of faults based on the vibration signal. Transient response-based crack detection technique has been developed and verified using simulation techniques. Rotor dynamics with transverse crack, coupling miss-alignment and rotor-stator rubbing can be represented using ordinary differential equations with time-periodic coefficients and intermittently varying coefficients. A new fault detection strategy based on short time Fourier transformation has been developed to detect the presence of crack and rotor stator rubbing even if the both coexist simultaneously. Due to the presence of unbalance, rotor systems with constant spinning speed are subjected to steady-state vibrations that can accelerate the crack growth or chances of rotor/stator rubbing action. During changes of the spinning speed, transient vibrations corresponding to resonance frequencies are also generated. To compensate both types of vibrations, a hybrid controller is successfully developed. Electromagnetic actuators are used to generate required control forces. From the spectrum of the control signal, rotor faults like transverse crack and coupling miss-alignment can be efficiently diagnosed. Applications of rotor dynamics can also be seen in machine tools. The spindle and ball screw drives are important examples of their applications. In the spindle, transverse and torsional vibrations are produced. However, in the ball screw drives, axial vibrations are generated. For precision control of the drives, a hybrid controller is proposed to increase command tracking efficiency and reduce the dynamic deflection of the carriage during metal cutting process. Experimental verification of the proposed controller has been done to verify its effectiveness. The dynamics of cutting tools is represented in the form of time-delay systems. Different time-domain algorithms are used to identify stable regions of machining operations. To improve the depth of cut, the active chatter control of turning and boring operations is carried out. Experimental results verify the effectiveness of the proposed active chatter control strategies. Based on the relative motion between the workpiece and cutting tool (during boring operation), cutting operations can be divided into different categories. The dynamics of such systems is represented using delay differential and time-periodic delay differential equations. Feasibility of active chatter control for each category is analyzed in detail. The effect of eccentricity and workpiece ovality on the dynamics of boring operations is thoroughly investigated. Linear Parameter Varying controllers are proposed to compensate for the changing dynamics of the system due to continuous metal removal in turning operations. Fractional-order proportional derivative controllers are designed using response optimization techniques and implemented in boring operations. Experimental results verify that these controllers save the control energy in active chatter control applications. Machine learning techniques are used for online chatter detections in milling operations. Various chatter indicators are proposed. Improved dynamic equations are proposed for milling operations to find the behaviour of vibrations during chatter conditions. Simulated data are used to train Convolutional Neural Networks that are then used to detect chatter in an online manner. Experimental results verify the effectiveness of the proposed technique.
Author | : Katia Lucchesi Cavalca |
Publisher | : Springer |
Total Pages | : 586 |
Release | : 2018-08-18 |
Genre | : Technology & Engineering |
ISBN | : 3319992686 |
IFToMM conferences have a history of success due to the various advances achieved in the field of rotor dynamics over the past three decades. These meetings have since become a leading global event, bringing together specialists from industry and academia to promote the exchange of knowledge, ideas, and information on the latest developments in the dynamics of rotating machinery. The scope of the conference is broad, including e.g. active components and vibration control, balancing, bearings, condition monitoring, dynamic analysis and stability, wind turbines and generators, electromechanical interactions in rotor dynamics and turbochargers. The proceedings are divided into four volumes. This second volume covers the following main topics: condition monitoring, fault diagnostics and prognostics; modal testing and identification; parametric and self-excitation in rotor dynamics; uncertainties, reliability and life predictions of rotating machinery; and torsional vibrations and geared systems dynamics.
Author | : Yukio Ishida |
Publisher | : John Wiley & Sons |
Total Pages | : 495 |
Release | : 2013-03-05 |
Genre | : Technology & Engineering |
ISBN | : 3527651918 |
A wide-ranging treatment of fundamental rotordynamics in order to serve engineers with the necessary knowledge to eliminate various vibration problems. New to this edition are three chapters on highly significant topics: Vibration Suppression - The chapter presents various methods and is a helpful guidance for professional engineers. Magnetic Bearings - The chapter provides fundamental knowledge and enables the reader to realize simple magnetic bearings in the laboratory. Some Practical Rotor Systems - The chapter explains various vibration characteristics of steam turbines and wind turbines. The contents of other chapters on Balancing, Vibrations due to Mechanical Elements, and Cracked Rotors are added to and revised extensively. The authors provide a classification of rotating shaft systems and general coverage of key ideas common to all branches of rotordynamics. They offers a unique analysis of dynamical problems, such as nonlinear rotordynamics, self-excited vibration, nonstationary vibration, and flow-induced oscillations. Nonlinear resonances are discussed in detail, as well as methods for shaft stability and various theoretical derivations and computational methods for analyzing rotors to determine and correct vibrations. This edition also includes case studies and problems.
Author | : Subashisa Dutta |
Publisher | : Springer Nature |
Total Pages | : 625 |
Release | : 2020-08-29 |
Genre | : Technology & Engineering |
ISBN | : 9811556938 |
This book consists of selected and peer-reviewed papers presented at the 13th International Conference on Vibration Problems (ICOVP 2017). The topics covered in this book are broadly related to the fields of structural health monitoring, vibration control and rotor dynamics. In the structural health monitoring section studies on nonlinear dynamic analysis, damage identification, viscoelastic model of concrete, and seismic damage assessment are thoroughly discussed with analytical and numerical techniques. The vibration control part includes topics such as multi-storeyed stacked tuned mass dampers, vibration isolation with elastomeric mounts, and nonlinear active vibration absorber. This book will be useful for beginners, researchers and professionals interested in the field of vibration control, structural health monitoring and rotor dynamics.
Author | : |
Publisher | : |
Total Pages | : 716 |
Release | : 1994 |
Genre | : Aeronautics |
ISBN | : |
Author | : Mohsen Nakhaeinejad |
Publisher | : |
Total Pages | : 282 |
Release | : 2010 |
Genre | : |
ISBN | : |
Modeling, fault assessment, and diagnostics of rolling element bearings and induction motors were studied. Dynamic model of rolling element bearings with faults were developed using vector bond graphs. The model incorporates gyroscopic and centrifugal effects, contact deflections and forces, contact slip and separations, and localized faults. Dents and pits on inner race, outer race and balls were modeled through surface profile changes. Experiments with healthy and faulty bearings validated the model. Bearing load zones under various radial loads and clearances were simulated. The model was used to study dynamics of faulty bearings. Effects of type, size and shape of faults on the vibration response and on dynamics of contacts in presence of localized faults were studied. A signal processing algorithm, called feature plot, based on variable window averaging and time feature extraction was proposed for diagnostics of rolling element bearings. Conducting experiments, faults such as dents, pits, and rough surfaces on inner race, balls, and outer race were detected and isolated using the feature plot technique. Time features such as shape factor, skewness, Kurtosis, peak value, crest factor, impulse factor and mean absolute deviation were used in feature plots. Performance of feature plots in bearing fault detection when finite numbers of samples are available was shown. Results suggest that the feature plot technique can detect and isolate localized faults and rough surface defects in rolling element bearings. The proposed diagnostic algorithm has the potential for other applications such as gearbox. A model-based diagnostic framework consisting of modeling, non-linear observability analysis, and parameter tuning was developed for three-phase induction motors. A bond graph model was developed and verified with experiments. Nonlinear observability based on Lie derivatives identified the most observable configuration of sensors and parameters. Continuous-discrete Extended Kalman Filter (EKF) technique was used for parameter tuning to detect stator and rotor faults, bearing friction, and mechanical loads from currents and speed signals. A dynamic process noise technique based on the validation index was implemented for EKF. Complex step Jacobian technique improved computational performance of EKF and observability analysis. Results suggest that motor faults, bearing rotational friction, and mechanical load of induction motors can be detected using model-based diagnostics as long as the configuration of sensors and parameters is observable.
Author | : Rajiv Tiwari |
Publisher | : CRC Press |
Total Pages | : 1225 |
Release | : 2017-11-22 |
Genre | : Science |
ISBN | : 1351863630 |
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 | : Wolfgang Borutzky |
Publisher | : Springer |
Total Pages | : 680 |
Release | : 2016-12-31 |
Genre | : Technology & Engineering |
ISBN | : 3319474340 |
This book presents theory and latest application work in Bond Graph methodology with a focus on: • Hybrid dynamical system models, • Model-based fault diagnosis, model-based fault tolerant control, fault prognosis • and also addresses • Open thermodynamic systems with compressible fluid flow, • Distributed parameter models of mechanical subsystems. In addition, the book covers various applications of current interest ranging from motorised wheelchairs, in-vivo surgery robots, walking machines to wind-turbines.The up-to-date presentation has been made possible by experts who are active members of the worldwide bond graph modelling community. This book is the completely revised 2nd edition of the 2011 Springer compilation text titled Bond Graph Modelling of Engineering Systems – Theory, Applications and Software Support. It extends the presentation of theory and applications of graph methodology by new developments and latest research results. Like the first edition, this book addresses readers in academia as well as practitioners in industry and invites experts in related fields to consider the potential and the state-of-the-art of bond graph modelling.
Author | : Rajiv Tiwari |
Publisher | : CRC Press |
Total Pages | : 1092 |
Release | : 2017-11-22 |
Genre | : Science |
ISBN | : 1351863649 |
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 | : Katia Lucchesi Cavalca |
Publisher | : Springer |
Total Pages | : 550 |
Release | : 2018-08-18 |
Genre | : Technology & Engineering |
ISBN | : 3319992708 |
IFToMM conferences have a history of success due to the various advances achieved in the field of rotor dynamics over the past three decades. These meetings have since become a leading global event, bringing together specialists from industry and academia to promote the exchange of knowledge, ideas, and information on the latest developments in the dynamics of rotating machinery. The scope of the conference is broad, including e.g. active components and vibration control, balancing, bearings, condition monitoring, dynamic analysis and stability, wind turbines and generators, electromechanical interactions in rotor dynamics and turbochargers. The proceedings are divided into four volumes. This third volume covers the following main topics: dynamic analysis and stability; electromechanical interactions in rotordynamics; nonlinear phenomena in rotordynamics; rotordynamics of micro, nano and cryogenic machines; and fluid structure interactions in rotordynamics.