The Experts below are selected from a list of 288 Experts worldwide ranked by ideXlab platform
S M Hashemidehkordi - One of the best experts on this subject based on the ideXlab platform.
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suppressing friction induced vibration due to Negative Damping and mode coupling effects using active force control
Australian journal of basic and applied sciences, 2010Co-Authors: S M Hashemidehkordi, Musa Mailah, A R AbubakarAbstract:This paper serves to highlight a potential and effective active force control (AFC) based scheme to suppress friction induced vibration that is caused by the mechanisms of Negative Damping and mode-coupling. Two mathematical models that are based on Shin and Hoffmann schemes are first simulated and analyzed using a conventional closed loop proportional-integral-derivative (PID) controller. Later, the models were seamlessly integrated with AFC elements to develop into a two degree-of-freedom (DOF) controller that is designed to effectively reject the disturbances and consequently reduce the vibrations in both models. It is found that the integrated PID-AFC scheme is very effective in suppressing vibration compared to the pure PID controller alone as clearly demonstrated through the results presented both in time and frequency domains.
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intelligent active force control with piezoelectric actuators to reduce friction induced vibration due to Negative Damping
International Review of Electrical Engineering-iree, 2010Co-Authors: Musa Mailah, Abdul Rahim Abu Bakar, S M HashemidehkordiAbstract:In this paper, a novel approach to reduce the effect of Negative Damping that causes friction induced vibration (FIV) is proposed by applying an intelligent active force control (AFC)-based strategy employing piezoelectric actuators with hysteresis effect to a simplified two degree-of-freedom mathematical model of a friction induced vibration system. At first, the model is simulated and analyzed using a closed loop pure proportional-integral-derivative (PID) controller. Later, it is integrated with the intelligent AFC with fuzzy logic (FL) estimator and simulated under similar operating condition. After running several tests with different sets of operating and loading conditions, the results both in time and frequency domains show that the PID controller with the intelligent AFC is much more effective in reducing the vibration, compared to the pure PID controller alone.
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an active control method to reduce the effect of Negative Damping in disk brake system
2009 Innovative Technologies in Intelligent Systems and Industrial Applications, 2009Co-Authors: S M Hashemidehkordi, Musa Mailah, Abd Rahim Abu BakarAbstract:In this paper, a novel approach to reduce the effect of Negative Damping that causes brake noise is proposed by applying an Active Force Control (AFC) based strategy to a two degree-of-freedom model of a disk brake system. At first, the disc brake model is simulated and analyzed using a closed loop pure PID controller. Later, it is integrated with AFC and simulated under similar operating environment. After running several tests with different sets of operating and loading conditions, the results both in time and frequency domains show that the PID controller with AFC is much more effective in reducing the vibration and noise, compared to the pure PID controller alone.
Musa Mailah - One of the best experts on this subject based on the ideXlab platform.
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suppressing friction induced vibration due to Negative Damping and mode coupling effects using active force control
Australian journal of basic and applied sciences, 2010Co-Authors: S M Hashemidehkordi, Musa Mailah, A R AbubakarAbstract:This paper serves to highlight a potential and effective active force control (AFC) based scheme to suppress friction induced vibration that is caused by the mechanisms of Negative Damping and mode-coupling. Two mathematical models that are based on Shin and Hoffmann schemes are first simulated and analyzed using a conventional closed loop proportional-integral-derivative (PID) controller. Later, the models were seamlessly integrated with AFC elements to develop into a two degree-of-freedom (DOF) controller that is designed to effectively reject the disturbances and consequently reduce the vibrations in both models. It is found that the integrated PID-AFC scheme is very effective in suppressing vibration compared to the pure PID controller alone as clearly demonstrated through the results presented both in time and frequency domains.
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intelligent active force control with piezoelectric actuators to reduce friction induced vibration due to Negative Damping
International Review of Electrical Engineering-iree, 2010Co-Authors: Musa Mailah, Abdul Rahim Abu Bakar, S M HashemidehkordiAbstract:In this paper, a novel approach to reduce the effect of Negative Damping that causes friction induced vibration (FIV) is proposed by applying an intelligent active force control (AFC)-based strategy employing piezoelectric actuators with hysteresis effect to a simplified two degree-of-freedom mathematical model of a friction induced vibration system. At first, the model is simulated and analyzed using a closed loop pure proportional-integral-derivative (PID) controller. Later, it is integrated with the intelligent AFC with fuzzy logic (FL) estimator and simulated under similar operating condition. After running several tests with different sets of operating and loading conditions, the results both in time and frequency domains show that the PID controller with the intelligent AFC is much more effective in reducing the vibration, compared to the pure PID controller alone.
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AN ACTIVE CONTROL METHOD TO REDUCE FRICTION INDUCED VIBRATION CAUSED BY Negative Damping
2009Co-Authors: S. M. Hashemi-dehkordi, Musa Mailah, Abd Rahim Abu BakarAbstract:In this paper, a novel approach to reduce the effec t of Negative Damping that causes friction induced vibration (FIV) is proposed by appl ying an active force control (AFC) based strategy to a simplified two degree-of-f reedom disk brake model. At first, the model is simulated and analyzed using a closed loop pure PID controller. Later, it is integrated with AFC and simulated under similar operating environment. After running several tests with different sets of operating and loading conditions, the results both in time and frequency domains show that the PID controller with AFC is much more effective in reducing the vibration , compared to the pure PID controller alone.
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an active control method to reduce the effect of Negative Damping in disk brake system
2009 Innovative Technologies in Intelligent Systems and Industrial Applications, 2009Co-Authors: S M Hashemidehkordi, Musa Mailah, Abd Rahim Abu BakarAbstract:In this paper, a novel approach to reduce the effect of Negative Damping that causes brake noise is proposed by applying an Active Force Control (AFC) based strategy to a two degree-of-freedom model of a disk brake system. At first, the disc brake model is simulated and analyzed using a closed loop pure PID controller. Later, it is integrated with AFC and simulated under similar operating environment. After running several tests with different sets of operating and loading conditions, the results both in time and frequency domains show that the PID controller with AFC is much more effective in reducing the vibration and noise, compared to the pure PID controller alone.
Kornel F Ehmann - One of the best experts on this subject based on the ideXlab platform.
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stability analysis of chatter in tandem rolling mills part 1 single and multi stand Negative Damping effect
Journal of Manufacturing Science and Engineering-transactions of The Asme, 2013Co-Authors: Huyue Zhao, Kornel F EhmannAbstract:Many different modes of chatter in rolling and their possible causes have been identified after years of research, yet no clear and definite theory of their mechanics has been fully established and accepted. In this two-part paper, stability of tandem mills is investigated. In Part 1, state-space models of single- and multi-stand chatter are formulated in a rigorous and comprehensive mathematical form. Then, the stability of the rolling system is investigated in the sense of the single- and multi-stand Negative Damping effects. First, a single-stand chatter model in state-space representation is proposed by coupling a dynamic rolling process model with a structural model for the mill stand. Subsequently, a multi-stand chatter model is developed by incorporating the inter-stand tension variations and the time delay effect of the strip transportation based on the single-stand chatter model. Stability criteria are proposed and stability analyses are performed to create corresponding stability charts in terms of the single- and multi-stand Negative Damping mechanism through numerical simulations. Particularly, the effect of friction conditions on chatter is examined and an explanation is given for the existence of an optimum friction condition. In Part 2, the regenerative effect and resulting instabilities are examined. Suitable stability criteria for each mechanism are established and stability charts are demonstrated in terms of relevant rolling process parameters.
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Stability Analysis of Chatter in Tandem Rolling Mills—Part 1: Single- and Multi-Stand Negative Damping Effect
Journal of Manufacturing Science and Engineering-transactions of The Asme, 2013Co-Authors: Huyue Zhao, Kornel F EhmannAbstract:Many different modes of chatter in rolling and their possible causes have been identified after years of research, yet no clear and definite theory of their mechanics has been fully established and accepted. In this two-part paper, stability of tandem mills is investigated. In Part 1, state-space models of single- and multi-stand chatter are formulated in a rigorous and comprehensive mathematical form. Then, the stability of the rolling system is investigated in the sense of the single- and multi-stand Negative Damping effects. First, a single-stand chatter model in state-space representation is proposed by coupling a dynamic rolling process model with a structural model for the mill stand. Subsequently, a multi-stand chatter model is developed by incorporating the inter-stand tension variations and the time delay effect of the strip transportation based on the single-stand chatter model. Stability criteria are proposed and stability analyses are performed to create corresponding stability charts in terms of the single- and multi-stand Negative Damping mechanism through numerical simulations. Particularly, the effect of friction conditions on chatter is examined and an explanation is given for the existence of an optimum friction condition. In Part 2, the regenerative effect and resulting instabilities are examined. Suitable stability criteria for each mechanism are established and stability charts are demonstrated in terms of relevant rolling process parameters.
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Regenerative Chatter in High-Speed Tandem Rolling Mills
Manufacturing Science and Engineering Parts A and B, 2006Co-Authors: Huyue Zhao, Kornel F EhmannAbstract:Third-octave-mode chatter, the most detrimental form of rolling chatter, is generated by means of Negative Damping, mode coupling, and regeneration. While mechanisms that include Negative Damping, and mode coupling have been thoroughly investigated, those associated with the regenerative effect remain elusive. In this paper, the mechanisms that may lead to regenerative chatter are studied through a state-space representation of a multi-stand mill that is constructed by coupling a homogenous dynamic rolling process model with a structural model for the mill stands in a high-speed tandem mill configuration. Stability analysis, by using the integral criterion for the stability of systems described by delay differential equations, is carried out for the regenerative mechanism in order to better understand the effects of rolling parameters on a single stand as well as the overall system. Preliminary simulation results, based on the proposed chatter model, are presented to demonstrate the feasibility and the accuracy of the chatter model, as well as to investigate chatter phenomena too complex to be studied analytically.Copyright © 2006 by ASME
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Chatter in the Strip Rolling Process, Part 3: Chatter Model
Journal of Manufacturing Science and Engineering-transactions of The Asme, 1998Co-Authors: Kornel F Ehmann, William R. D. WilsonAbstract:The central problem of the analysis and prevention of chatter in rolling operations is in understanding the conditions which lead to dynamic instability. By analogy with metal cutting operations, it appears that a few basic mechanisms may be responsible for the occurrence of self-excited vibrations in rolling. The three most significant mechanisms are: Negative Damping, mode-coupling and regeneration. In this paper, Negative Damping and mode-coupling are considered separately in an artificial manner to make inroads towards a better basic understanding of rolling instability.
Abdul Rahim Abu Bakar - One of the best experts on this subject based on the ideXlab platform.
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intelligent active force control with piezoelectric actuators to reduce friction induced vibration due to Negative Damping
International Review of Electrical Engineering-iree, 2010Co-Authors: Musa Mailah, Abdul Rahim Abu Bakar, S M HashemidehkordiAbstract:In this paper, a novel approach to reduce the effect of Negative Damping that causes friction induced vibration (FIV) is proposed by applying an intelligent active force control (AFC)-based strategy employing piezoelectric actuators with hysteresis effect to a simplified two degree-of-freedom mathematical model of a friction induced vibration system. At first, the model is simulated and analyzed using a closed loop pure proportional-integral-derivative (PID) controller. Later, it is integrated with the intelligent AFC with fuzzy logic (FL) estimator and simulated under similar operating condition. After running several tests with different sets of operating and loading conditions, the results both in time and frequency domains show that the PID controller with the intelligent AFC is much more effective in reducing the vibration, compared to the pure PID controller alone.
Hao Wang - One of the best experts on this subject based on the ideXlab platform.
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Development of Coupled Program fast-simdyn and Study of Non-Linear Hydrodynamics, Coupled With Negative Damping and Aerodynamics of Floating Offshore Wind Turbines
Journal of Offshore Mechanics and Arctic Engineering-transactions of The Asme, 2019Co-Authors: Alwin Jose, Jeffrey M. Falzarano, Hao WangAbstract:Abstract Non-linear hydrostatic and wave forces on floating structures are very important during large amplitude waves. The computer program simdyn is a blended time domain program developed by Marine Dynamics Laboratory at TAMU and is capable of capturing the role of non-linear fluid forces. simdyn has previously been used to demonstrate that nonlinear hydrostatics have become very important in the problem of parametric excitation. In the current work simdyn is coupled with the computer program fast developed by U.S. National Renewable Energy Laboratory (NREL) for numerical simulation of floating offshore wind turbines (FOWTs). fast-simdyn is now a tool that is capable of studying large amplitude motions of FOWTs in extreme seas. fast-simdyn was then used to study the classic instability of Negative Damping that occurs in FOWTs that use conventional land-based control. The development of platform pitch and platform surge instability are studied in relation to different wave and wind scenarios. The intent was to do an analysis to see if the non-linear forces do play a significant role in large amplitude motions induced by Negative Damping. This study gives an indication of whether the development and application of higher fidelity hydrodynamic modules are justified.
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A Study of Negative Damping in Floating Wind Turbines Using Coupled Program FAST-SIMDYN
ASME 2018 1st International Offshore Wind Technical Conference, 2018Co-Authors: Alwin Jose, Jeffrey M. Falzarano, Hao WangAbstract:The Floating Offshore Wind Turbine (FOWT) is a fairly new concept. There are limited number of full-scale prototypes to provide real data. Therefore, most of the research today relies on numerical models. This is required, so that an adequate amount of confidence can be gained before venturing into large scale production. The major challenge ahead is proving their reliability and robustness. There needs to be supporting studies that consider most factors that can go wrong. The computer program FAST was a groundbreaking contribution from NREL in this regard. FAST is capable of doing combined loading analysis of FOWTs. The numerical model used for the hydrodynamics can, however, be improved further. Non-linear hydrostatic and wave forces on floating structures become very important during large amplitude waves. The computer program SIMDYN is a blended time domain program developed by Marine Dynamics Laboratory at TAMU and is capable of capturing the role of non-linear fluid forces. SIMDYN has previously been used to demonstrate that nonlinear hydrostatics become very important in the problem of parametric excitation. In the current work, SIMDYN is coupled with FAST. The FAST-SIMDYN is now a tool that is capable of studying large amplitude motions of FOWTs in extreme seas. FAST-SIMDYN was then used to study the classic instability of Negative Damping that occurs in FOWTs that use conventional land based control. The development of platform pitch and platform surge instability are studied in relation to different wave and wind scenarios. The intent was to do an analysis to see if the non-linear forces do play a significant role in large amplitude motions induced by Negative Damping. This study gives an indication of whether the development of an even more sophisticated hydrodynamic modules is justified.
