Browsing by Author "El-Sayed, A. T."

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Control of a two-degree-of-freedom system with combined excitations
(ELSEVIER, 2015) Bauomy, H. S.; El-Sayed, A. T.
In this paper, the chaotic dynamics of parametrically, externally and tuned excited suspended cable is studied with negative cubic velocity feedback. The equations of motion of this system are exhibited by two-degree-of-freedom system including quadratic and cubic nonlinearities. Using the multiple scale perturbation technique, the response of the nonlinear system near the simultaneous primary, sub-harmonic, combined and internal resonance case of this system is extracted up to the second order approximation. The stability of the obtained numerical solution is investigated using frequency response equations. The effect of different parameters on the vibrating system behavior are investigated and reported. The simulation results are achieved using MATLAB (R2012a) programs. (C) 2014 Politechnika Wroclawska. Published by Elsevier Urban & Partner Sp. z.o.o. All rights reserved.
Outcome of special vibration controller techniques linked to a cracked beam
(ELSEVIER SCIENCE INC, 2018-11) Bauomy, H.S.; El-Sayed, A. T.
This paper presents a comparison between three different controller methods added to a cracked beam under the action of a harmonic excitation. Those three controllers are Positive Position Feedback (PPF), Integral Resonant Control (IRC) and Nonlinear Integral Positive Position Feedback (NIPPF) which be added to the measured system. The multiple scales method (MSM) is applied for getting the approximate solution on behalf of measured design. This method is effective to solve the major equations of measured system. Stability and effect of different coefficients of the system are demonstrated. The approximate solution response is established via numerical simulation outcome. NIPPF controller is the best one gives better results compared to the other two controllers in decreasing the high amplitude of the system. Comparison between mathematical solution and numerical simulation are considered. Relationship of formerly available papers is considered. (C) 2018 Elsevier Inc. All rights reserved.
Torsional vibration reduction for rolling mill's main drive system via negative velocity feedback under parametric excitation
(KOREAN SOC MECHANICAL ENGINEERS, 2015) Amer, Y. A.; El-Sayed, A. T.; El-Bahrawy, F. T.
Torsional vibration characteristics are important information for rotating machinery design and control. Jointed shaft is a commonly used element in drive trains of rolling mill. The torsional vibrations of one-degree -of freedom nonlinear dynamical system are controlled using active control. The multiple scale perturbation technique used to get the approximate solution of the differential equation describes the system. The worst resonance cases were deduced and the frequency response function are obtained. The stability and steady state response of the system are studied and discussed numerically. The numerical solutions are focused on both the effects of the different parameters and the system behavior at different resonance cases. To insure the validity of the results, a comparison between the numerical and analytical solution was presented.
Vibration control of helicopter blade flapping via time-delay absorber
(SPRINGER, 2014) El-Sayed, A. T.; Bauomy, H. S.
In this study, the controller is used to suppress the vibration due to rotor the helicopter blade flapping motion. The objective of this paper is to investigate the effect of time-delay absorber on the vibrating system when subjected to multi-parametric excitation forces. The equations of motion are described by coupled nonlinear differential equations. The averaging method is applied to obtain the frequency response equations near simultaneous sub-harmonic and internal resonance. The stability of the obtained nonlinear solution is studied and solved numerically. Numerical simulations show the steady state response amplitude versus the detuning parameter and the effects of the parameters system and controller. Effectiveness of the absorber E-a is about 2.7x10(5) of the main system (X).
Vibration reduction of a nonlinear spring pendulum under multi external and parametric excitations via a longitudinal absorber
(SPRINGER, 2011) Eissa, M.; Kamel, M.; El-Sayed, A. T.
The vibration of a ship pitch-roll motion described by a non-linear spring pendulum system (two degrees of freedom) subjected to multi external and parametric excitations can be reduced using a longitudinal absorber. The method of multiple scale perturbation technique (MSPT) is applied to analyze the response of this system near the simultaneous primary, sub-harmonic and internal resonance. The steady state solution near this resonance case is determined and studied applying Lyapunov's first method. The stability of the system is investigated using frequency response equations. Numerical simulations are extensive investigations to illustrate the effects of the absorber and some system parameters at selected values on the vibrating system. The simulation results are achieved using MATLAB 7.0 programs. Results are compared to previously published work.
Vibration reduction of a pitch-roll ship model with longitudinal and transverse absorbers under multi excitations
(PERGAMON-ELSEVIER, 2010) El-Sayed, A. T.; Kamel, M.; Eissa, M.
This paper presents an application of passive vibration control to a non-linear spring pendulum system simulating a ship's roll motion. This leads to a four-degree-of-freedom (4-DOF) system subjected to multi external and parametric excitations. Two absorbers in the longitudinal and transverse directions are designed to control the vibration near the simultaneous primary, sub-harmonic and internal resonance where system damage is probable. The theoretical results are obtained to second order approximations applying the multiple scale perturbation technique (MSPT). The stability of the steady-state solution near the simultaneous resonance case is investigated and studied applying frequency response equations. The effects of the absorbers and some system parameters on the vibrating system are studied numerically. The simulation results are achieved using MATLAB 7.0 programs Shampine et al. (2003) [16]. Comparison with the available published work is reported. (c) 2010 Elsevier Ltd. All rights reserved.
Vibration reduction of multi-parametric excited spring pendulum via a transversally tuned absorber
(SPRINGER, 2010) Eissa, M.; Kamel, M.; El-Sayed, A. T.
The use of passive control strategy is a common way to stabilize and control dangerous vibrations in a nonlinear spring pendulum which is describing the ship's roll motion. In this paper, a tuned absorber in the transversal direction is connected to a spring pendulum with multi-parametric excitation forces to control the vibration due to some resonance cases on the system. The method of multiple scale perturbation technique (MSPT) is applied to study the periodic solution of the given system near simultaneous sub-harmonic and internal resonance case. The stability of the steady-state solution near the resonance case is investigated and studied using frequency response equations. The effects of the absorber and some system parameters on the vibrating system are studied numerically. Optimal working conditions of the system are extracted when applying passive control methods. Comparison with the available published work is reported.
Vibration Suppression of a Four-Degrees-of-Freedom Nonlinear Spring Pendulum via Longitudinal and Transverse Absorbers
(ASME-AMER SOC MECHANICAL ENG, 2012) Eissa, M.; Kamel, M.; El-Sayed, A. T.
An investigation into the passive vibration reduction of the nonlinear spring pendulum system, simulating the ship roll motion is presented. This leads to a four-degree-of-freedom (4-DOF) system subjected to multiparametric excitation forces. The two absorbers in the longitudinal and transverse directions are usually designed to control the vibration near the simultaneous subharmonic and internal resonance where system damage is probable. The theoretical results are obtained by applying the multiple scale perturbation technique (MSPT). The stability of the obtained nonlinear solution is studied and solved numerically. The obtained results from the frequency response curves confirmed the numerical results which were obtained using time history. For validity, the numerical solution is compared with the analytical solution. Effectiveness of the absorbers (Ea) are about 13 000 for the first mode (x) and 10 000 for the second mode (phi). A threshold value of linear damping coefficient can be used directly for vibration suppression of both vibration modes. Comparison with the available published work is reported. [DOI: 10.1115/1.4004551]