Abdallah Galal

Dr. Abdallah Galal

orcid

Research Focus & Metrics

Academic Career Length

6Years (2021-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 March 2022 in Journal of Low Frequency Noise, Vibration and Active Control
Verified
Journal Article
Open access
CHChun-Hui He
Chun-Hui He
TATarek S Amer
Tarek S Amer
DTDan Tian
Dan Tian
AAAmany F Abolila
Amany F Abolila
AGAbdallah Galal
Abdallah Galal
This work focuses on vibration alleviation and energy harvesting in a dynamical system of a spring-pendulum. The structure of the pendulum is modified using an independent electromagnetic harvesting system. The harvesting depends on the oscillation of a magnet in a coil. An endeavor has been made to get both the energy harvesting and mitigation of vibration efficacy of the harvester. The governing kinematics equations are derived using Lagrange’s equations and are solved asymptotically using the multiple scales method to achieve the intended outcome as new and precise results. The resonance states are classified, and the influence of various parameters of the studied system is analyzed. Fixed points at steady states are categorized into stable and unstable. The time behavior of the solutions, the modified amplitudes, and phases are examined and interpreted in the light of their graphical plots. Zones of stability and instability are concerned, in which the system’s behavior is stable for a wide range of used parameters. This model has become essential in recent times as it uses control sensors in industrial applications, buildings, infrastructure, automobiles, and transportation.

18 August 2021 in Axioms
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Journal Article
Open access
PDF file
Ji-Huan HeJi-Huan He
Ji-Huan He
Tarek AmerTarek Amer
Tarek Amer
SEShimaa Elnaggar
Shimaa Elnaggar
AGAbdallah Galal
Abdallah Galal
The current paper investigates the dynamical property of a pendulum attached to a rotating rigid frame with a constant angular velocity about the vertical axis passing to the pivot point of the pendulum. He’s homotopy perturbation method is used to obtain the analytic solution of the governing nonlinear differential equation of motion. The fourth-order Runge-Kutta method (RKM) and He’s frequency formulation are used to verify the high accuracy of the obtained solution. The stability condition of the motion is examined and discussed. Some plots of the time histories of the gained solutions are portrayed graphically to reveal the impact of the distinct parameters on the dynamical motion.

3 March 2025 in Journal of Low Frequency Noise, Vibration and Active Control
Verified
Journal Article
Open access
Tarek AmerTarek Amer
Tarek Amer
HEHf El-Kafly
Hf El-Kafly
A. H. ElneklawyA. H. Elneklawy
A. H. Elneklawy
AGAbdallah Galal
Abdallah Galal
This is a new study that examines how a rigid body (RGB) reacts to the influence of constant body-fixed torques and gyrostatic torques (GT), as well as the impact of energy dissipation. The RGB’s model being studied includes a spherical slug near the center of mass covered by a viscid layer. Understanding the behavior of this model can offer insights into how RGBs respond to external torques, aiding in the development of more efficient and stable systems for aerospace and robotics applications. The research delves into the relationship between energy dissipation and the GT on the RGB’s motion in three different scenarios involving constant torques around various axes. Detailed analysis, as well as novel simulated results, is presented for different energy dissipation possibilities, such as equilibrium manifolds, periodic or non-periodic solutions, and separatrix surfaces. These new findings are crucial for comprehending, maintaining, and controlling the motion of rigid celestial bodies influenced by external forces in space. The study promises to have a significant impact on the aerospace industry, particularly in the design and operation of spaceships, spacecraft, and satellites, by enhancing our knowledge of rotational motion and celestial bodies’ behavior. A comprehensive report will be produced to elucidate the complexities of rotational and orbital motion discovered during this research.

20 November 2023 in Scientific Reports
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Journal Article
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GMGalal M. Moatimid
Galal M. Moatimid
TAT. S. Amer
T. S. Amer
AGAbdallah Galal
Abdallah Galal
Due to the growing concentration in the field of the nonlinear oscillators (NOSs), the present study aims to use the general He's frequency formula (HFF) to examine the analytical representations for particular kinds of strong NOSs. Three real-world examples are demonstrated by a variety of engineering and scientific disciplines. The new approach is evidently simple and requires less computation than the other perturbation techniques used in this field. The new methodology that is termed as the non-perturbative methodology (NPM) refers to this innovatory strategy, which merely transforms the nonlinear ordinary differential equation (ODE) into a linear one. The method yields a new frequency that is equivalent to the linear ODE as well as a new damping term that may be produced. A thorough explanation of the NPM is offered for the reader's convenience. A numerical comparison utilizing the Mathematical Software (MS) is used to verify the theoretical results. The precise numeric and theoretical solutions exhibited excellent consistency. As is commonly recognized, when the restoration forces are in effect, all traditional perturbation procedures employ Taylor expansion to expand these forces and then reduce the complexity of the specified problem. This susceptibility no longer exists in the presence of the non-perturbative solution (NPS). Additionally, with the NPM, which was not achievable with older conventional approaches, one can scrutinize examining the problem's stability. The NPS is therefore a more reliable source when examining approximations of solutions for severe NOSs. In fact, the above two reasons create the novelty of the present approach. The NPS is also readily transferable for additional nonlinear issues, making it a useful tool in the fields of applied science and engineering, especially in the topic of the dynamical systems.

4 August 2022 in Nonlinear Dynamics
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Journal Article
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Tarek AmerTarek Amer
Tarek Amer
FEF. M. El-Sabaa
F. M. El-Sabaa
SZS. K. Zakria
S. K. Zakria
AGAbdallah Galal
Abdallah Galal
In this article, the motion of three degree-of-freedom (DOF) dynamical system consisting of a triple rigid body pendulum (TRBP) in the presence of three harmonically external moments is studied. In view of the generalized coordinates of the system, Lagrange's equations are used to obtain the governing system of equations of motion (EOM). The analytic approximate solutions are gained up to the third approximation utilizing the approach of multiple scales (AMS) as novel solutions. The solvability conditions are determined in accordance with the elimination of secular terms. Therefore, the arising various resonances cases have been categorized and the equations of modulation have been achieved. The temporal histories of the obtained approximate solutions, as well as the resonance curves, are visually displayed to reveal the positive effects of the various parameters on the dynamical motion. The numerical results of the governing system are achieved using the fourth-order Runge–Kutta method. The visually depicted comparison of asymptotic and numerical solutions demonstrates high accuracy of the employed perturbation approach. The criteria of Routh–Hurwitz are used to investigate the stability and instability zones, which are then analyzed in terms of steady-state solutions. The strength of this work stems from its uses in engineering vibrational control applications which carry the investigated system a huge amount of importance.

9 September 2024 in Nonlinear Dynamics
Verified
Journal Article
Open access
PDF file
Tarek AmerTarek Amer
Tarek Amer
GMGalal M. Moatimid
Galal M. Moatimid
SZS. K. Zakria
S. K. Zakria
AGAbdallah Galal
Abdallah Galal
The focus of this paper is to examine the motion of a novel double pendulum (DP) system with two degrees of freedom (DOF). This system operates under specific constraints to follow a Lissajous curve, with its pivot point moving along this path in a plane. The nonlinear differential equations governing this system are derived using Lagrange's equations. Their analytical solutions (AS) are subsequently calculated using the multiple-scales method (MSM), which provides higher-order approximations. These solutions are considered new, as the traditional MSM has been applied to this novel system for the first time. Additionally, the accuracy of these solutions is validated through numerical results obtained using the fourth-order Runge–Kutta method. The solvability conditions and characteristic exponents are determined based on resonance cases. The Routh–Hurwitz criteria (RHC) are employed to assess the stability of the fixed points corresponding to the steady-state solutions. They are also used to demonstrate the frequency response curves. The nonlinear stability analysis is performed by examining the stability and instability ranges. Resonance curves and time history plots are presented to analyze the behavior of the system for specific parameter values. The investigation delves into a comprehensive analysis of bifurcation diagrams (BDs) and Lyapunov exponent spectra (LEs), aiming to uncover the various types of motion present within the system. Systematic examination of these charts reveals critical insights into transitions between stable, quasi-stable, and chaotic dynamical behaviors. This work has practical applications in various fields, such as robotics, pump compressors, rotor dynamics, and transportation devices. It can be used to study the vibrational motion of these systems.