Kafrelsheikh University, Faculty of Science, Mathematics Department Teaching Assistant/Kafrelsheikh University, Faculty of Science, Mathematics Department
I am currently employed with Kafrelsheikh University's Faculty of Science, Mathematics Department, as a Teaching Assistant. Theoretical Mechanics is the main field in which I conduct my research. Additionally, I serve as a peer reviewer for the top-ranked journals in the field. Recently, I have been assigned as an editor for the eVitroKhem Journal.
EDUCATION
B.Sc. in Mathematics 2013-2017.
M.Sc. in Applied Mathematics (Theoretical Mechanics) 2022-2024.
Ph.D. in Applied Mathematics (Theoretical Mechanics) 2024 till now.
RESEARCH, TEACHING, or OTHER INTERESTS
Applied Mathematics, Computational Mathematics, Astronomy and Astrophysics, Mathematical Physics
20
Scopus Publications
1015
Scholar Citations
16
Scholar h-index
16
Scholar i10-index
Scopus Publications
Optimization of asymmetric gyrostatic satellite kinematics in a resistive medium: A novel elliptic function solution A. H. Elneklawy, T. S. Amer, S. A. Elkilany, A. S. Abo Seliem, N. Hegazy Scientific Reports, 2026 In this study, a new approach for solving the dynamic motion of an asymmetric satellite with optimally controlled torques is investigated. The satellite moves in an atmospheric resistance medium and is impacted by gyrostatic torque (GT). The Euler equations were used to formulate the governing satellite equations. A small parameter is introduced through the assumption of a small control torque magnitude. Using elliptic function theory, explicit expressions for the angular velocities in the unperturbed regime are derived, extending the classical Euler-Poinsot solutions to include coupled gyrostatic and control effects. The semi-optimal control law is derived from a minimum-energy objective functional and is shown to preserve the integrability structure of the system. Perturbation analysis yields evolution equations for the angular momentum and kinetic energy in the presence of resistive torques. Numerical validation outcomes with < 10 -6 relative error over 100 rotation periods. Parametric studies reveal distinct operational regimes: gyrostatic amplification enhances momentum capacity while maintaining stability; medium resistance provides stabilization but increases compensatory energy consumption; and control axes exhibit specialized roles, with b 2 serving as the primary momentum driver and b 3 exhibiting inverse energy relationships. The analytical framework provides a 100x computational speedup for mission design optimization compared to direct numerical integration, with applications to the attitude control of asymmetric satellites in low Earth orbit. The findings directly apply to low-Earth-orbit satellites experiencing atmospheric drag, where optimal power management is crucial for mission longevity. Earth observation satellites, communication satellites, and space telescopes with complex, nonsymmetric geometries can benefit from the developed control torque optimization strategies, especially the discovery that different control axes serve specialized roles in energy management and attitude stability. The study’s insights into GT effects are particularly valuable for spacecraft with large spinning components, such as solar arrays or antennas, whereas elliptic modulus analysis provides essential guidance for mission planning and attitude determination algorithms.
Rotational Dynamics and Stability of Gyrostatic Systems with Prescribed Internal Mass Motion: Asymptotic Methods and Spacecraft Attitude Control Rageh K. Hussein, M. A. Ibrahem, T. S. Amer, A. H. Elneklawy Mathematics, 2026 This paper examines the rotational motion of a compound mechanical system comprising a rigid carrier body equipped with internal gyroscopic devices and a point mass that moves along a prescribed trajectory relative to the body. The system undergoes free motion in a uniform gravitational field. We derive the complete equations of motion accounting for the constant gyrostatic torque (GT) generated by internal rotors. Using asymptotic methods, we develop approximate dynamical equations valid under two distinct physical scenarios: (i) when the moving mass is small relative to the carrier mass and executes rapid oscillations and (ii) when the mass oscillates with small amplitude near a fixed location within the body, regardless of mass ratio. The accuracy and validity range of these approximations are rigorously established. For the first scenario, we have approached the idea that gyrostatic coupling fundamentally alters the system’s integrability properties while introducing beneficial stabilization mechanisms. We characterize families of permanent rotational states and analyze their stability using linear perturbation theory. The second scenario reveals that the approximate dynamics correspond to gyrostat motion rather than the classical Euler–Poinsot case. Comprehensive numerical simulations validate theoretical predictions and demonstrate applications to spacecraft attitude control problems. The results provide practical design guidelines for gyrostabilized systems with internal moving components.
Nonlinear dynamical behavior of a three-degree-of-freedom asymmetric rigid body under gyroscopic torque A. H. Elneklawy, T. S. Amer, Asma Alanazy, H. F. El-Kafly, A. A. Sallam Journal of Low Frequency Noise Vibration and Active Control, 2026 The study in this paper focuses on solving the problem of rigid body (RB) rotary motion under the effect of both gyrostatic torque (GT) and the body’s constant fixed torques (BCFTs). The controlling equations of motion (EOMs), in such a case, are derived from Euler’s kinematic equations. Novel analytical solutions for the body angular velocities are approached in three instances: major, minor, and intermediate with a detailed description of the stability regions, equilibrium points (EPs), and the motion critical points. The extreme value of the case is also examined, with stabilization addressed in two sections. Each section offers a solution and includes a table of extreme values within the stable separatrix region. Additionally, the effect of distinct GT values on the motion’s paths and stabilization is analyzed, resulting in valuable insights for this scenario. For each case, a comprehensive estimation of the maximum values and minimum ones at distinct non-dimensional angular velocity components (NAVCs) in addition to periodic solutions has been approached. A contour mapping for the motion is presented to see the influence of the GT on the separatrix surfaces (SS), non-periodic or periodic solutions, and extreme periodic ones. Moreover, a three-dimensional (3D) representation of the numerical solution in the intermediate case was presented to also reveal the GT impact. The significant implications of these findings are clear in systems’ designing and evaluation utilizing asymmetric RBs, such as spaceships. This research could inspire further exploration of different perspectives within the GT in comparable scenarios, potentially impacting numerous fields, such as the engineering industry and navigation.
Energy Decay in a Gyrostatically Influenced Rigid Body T. S. Amer, H. F. El-Kafly, A. H. Elneklawy, A. A. Galal Journal of Vibration Engineering and Technologies, 2026 The rotational motion of rigid bodies (RBs) subjected to external torques is fundamental to understanding dynamics in various engineering applications. A RB model comprising a spherical slug centered near the RB's center of mass, covered by a viscid layer, provides valuable insights into RB dynamics when exposed to external torques. Analyzing such systems' stability is essential for designing efficient and stable systems in aerospace and robotics, particularly for spacecraft and satellites involving rotor-stabilization, internal moving masses, and fuel sloshing. This study examines the rotational dynamics of a semi-RB under constant body-fixed torques (CBFTs) and a gyrostatic moment (GM), considering internal energy dissipation (ED). The impacts of ED alongside GM on the body's motion are explored in three cases involving constant torque about the major, minor, and intermediate axes. A non-dimensional model is developed, reducing the system's reliance to five fundamental parameters. Linear stability analysis is performed to assess the stability of various equilibrium points (EPs) concerning torques around different principal axes. Extensive numerical simulations are conducted to investigate the global dynamics. For major axis torque, the system settles into a pure spin-up maneuver, with viscosity and GM affecting the transient path and final spin amplitude. For minor axis torque, no EPs exist, and trajectories continuously evolve while crossing separatrices. For intermediate axis torque, motion can remain in certain phase space regions or transition between them, with GM serving as a critical control parameter. Analysis of perturbed motion confirmed linear stability predictions, with trajectories forming stable or unstable oscillations around equilibria. Novel outcomes include equilibrium manifolds, periodic and non-periodic solutions, and separatrix surfaces. These findings directly impact the design and attitude control of aerospace systems, including spacecraft and satellites. The identified stability regions and transition behaviors can inform control law design and maneuver planning for celestial RB motion in space.
Nonlinear Dynamical Motion of a Nearly Spherical Gyrostat Containing a Spherical Slug Filled with a Viscous Liquid A. H. Elneklawy, T. S. Amer, H. F. El-Kafly Journal of Nonlinear Mathematical Physics, 2025 The present work is concerned with the nonlinear dynamical motion of a quasi-spherical gyrostat containing a spherical slug filled with a viscous fluid. The governing system of nonlinear equations is derived and subsequently transformed into a non-dimensional form. The average method is used to approach a solution for the system. To stand on a small parameter in the problem, the Reynolds number is assumed to be tiny and yet implies that the kinematic viscosity coefficient is too large, for which its inverse quantity is chosen to be the small parameter. The body’s motion is influenced by torque from the internal liquid and by the gyrostatic torque (GT). By applying the averaging method to the non-dimensional equations, we eliminate the effects of the first two GT components, leaving only the influence of the third component. The influence of the third torque component is demonstrated through graphical simulations to analyze the body’s motion under various values of this torque. The obtained outcomes have practical applications in fields such as spacecraft spin-stabilization with propellant slosh, the modeling of Earth-core wobble and planetary nutation, and the design of high-precision, fluid-damped gyroscopes and stabilizers.
Application of Krylov–Bogoliubov–Mitropolski method to asymmetric gyrostatic 3D motion in multi-fields T. S. Amer, A. H. Elneklawy, H. F. El-Kafly Scientific Reports, 2025 The 3D rotary movement of an asymmetric rigid body (RB) in space around a fixed point is investigated. A gyrostatic torque (GT), a magnetic field (MF), and a Newtonian force field (NFF) all have an impact on the RB’s ability to rotate. Around its minor axis of inertia, the body is thought to begin moving rapidly. The Krylov–Bogoliubov–Mitropolski (KBM) method is used to solve the governing equations of motion (EOMs) analytically once they are created using Euler–Poisson equations. Additionally, Euler angles approximate analytical solutions (AS) are examined. A graphical simulated viewpoint of the obtained results and the equations of Euler angles, which show how the body is orientated at each given moment, are used to debate the interpretation of the motion. Maintaining control over the body’s rotation and position during motion can be achieved by researching the effects of different values of the acting forces and toques, such as the GT, MF, and NFF. To illustrate how the stability of the RB is affected, phase graphs of various solutions have been created. Periodicity behavior is demonstrated by the closed-phase curves’ symmetry around any of their axes. Together with the beneficial impacts of these forces and torques, the movement behavior of the RB is evaluated and simulated. The results obtained are widely relevant to gyroscopic equipment, especially those that incorporate inertial systems like aircraft and satellites. Technologies that guarantee the motion stability of applications are also included.
Optimal stabilization of rotational motion for a charged spacecraft with viscous fluid: Analytical and numerical analysis AH Elneklawy, TS Amer, SA Elkilany, ASA Seliem, N Hegazy CEAS Space Journal, 1-21 , 2026 2026
Rotational Dynamics and Stability of Gyrostatic Systems with Prescribed Internal Mass Motion: Asymptotic Methods and Spacecraft Attitude Control RK Hussein, MA Ibrahem, TS Amer, AH Elneklawy Mathematics 14 (9), 1463 , 2026 2026 Citations: 1
Optimization of asymmetric gyrostatic satellite kinematics in a resistive medium: A novel elliptic function solution AH Elneklawy, TS Amer, SA Elkilany, ASA Seliem, N Hegazy Scientific Reports 16 (1), 12212 , 2026 2026 Citations: 1
Semi-analytic solutions for finite-rotation attitude dynamics of gyrostatic rigid bodies TS Amer, RK Hussein, EA Ivanova, AH Elneklawy European Journal of Mechanics-A/Solids, 106131 , 2026 2026 Citations: 3
Nonlinear dynamical behavior of a three-degree-of-freedom asymmetric rigid body under gyroscopic torque AH Elneklawy, TS Amer, A Alanazy, HF El-Kafly, AA Sallam Journal of Low Frequency Noise, Vibration and Active Control 45 (1), 150-177 , 2026 2026 Citations: 20
Energy Decay in a Gyrostatically Influenced Rigid Body TS Amer, HF El-Kafly, AH Elneklawy, AA Galal Journal of Vibration Engineering & Technologies 14 (2), 93 , 2026 2026 Citations: 5
Nonlinear Dynamical Motion of a Nearly Spherical Gyrostat Containing a Spherical Slug Filled with a Viscous Liquid AH Elneklawy, TS Amer, HF El-Kafly Journal of Nonlinear Mathematical Physics 32 (1), 19 , 2025 2025 Citations: 17
Application of Krylov–Bogoliubov–Mitropolski method to asymmetric gyrostatic 3D motion in multi-fields TS Amer, AH Elneklawy, HF El-Kafly Scientific Reports 15 (1), 42548 , 2025 2025 Citations: 21
Damping-based attitude control of a gyrostatic satellite in resistive media AH Elneklawy, TS Amer, SA Elkilany, AS Abo Seliem, N Hegazy Journal of Applied and Computational Mechanics, e19528 , 2025 2025 Citations: 26
Asymptotic Solutions for the 3D Motion of Asymmetric Charged Gyrostatic Satellite Using Poincaré Small Parameter Technique TS Amer, A Alanazy, AH Elneklawy, WS Amer, HF El-Kafly Aerospace Science and Technology 168 (Part A), 110764 , 2025 2025 Citations: 56
Stability analysis of a rotating rigid body: The role of external and gyroscopic torques with energy dissipation TS Amer, HF El-Kafly, AH Elneklawy, AA Galal Journal of Low Frequency Noise, Vibration and Active Control 44 (3), 1502-1515 , 2025 2025 Citations: 56
Analyzing the Motion of a Charged Rigid Body under the Influence of a Gyrostatic Torque AH Elneklawy Engineering and Technology for Sustainable Development: Higher Institute of … , 2025 2025 Citations: 1
Dynamical motion of a spacecraft containing a slug and influenced by a gyrostatic moment and constant torques TS Amer, AH Elneklawy, HF El-Kafly Journal of Low Frequency Noise, Vibration and Active Control 44 (3), 1708-1725 , 2025 2025 Citations: 50
Modeling of the Euler-Poisson equations for rigid bodies in the context of the gyrostatic influences: an innovative methodology TS Amer, WS Amer, M Fakharany, AH Elneklawy, HF El-Kafly European Journal of Pure and Applied Mathematics 18 (1), 5712-5712 , 2025 2025 Citations: 33
Humanity's last exam L Phan, A Gatti, Z Han, N Li, J Hu, H Zhang, CBC Zhang, M Shaaban, ... arXiv preprint arXiv:2501.14249 , 2025 2025 Citations: 496
A novel study on the fourth first integral for the rotatory motion of an impacted charged rigid body by external torques TS Amer, A Alanazy, AH Elneklawy, WS Amer, HF El-Kafly Journal of Low Frequency Noise, Vibration and Active Control 44 (4), 1949-1960 , 2025 2025 Citations: 27
Analysis of Euler’s equations for a symmetric rigid body subject to time-dependent gyrostatic torque TS Amer, AH Elneklawy, HF El-Kafly Journal of Low Frequency Noise, Vibration and Active Control 44 (2), 831-843 , 2025 2025 Citations: 31
Modeling analysis on the influence of the gyrostatic moment on the motion of a charged rigid body subjected to constant axial torque TS Amer, HF El-Kafly, AH Elneklawy, WS Amer Journal of Low Frequency Noise, Vibration and Active Control 43 (4), 1593-1610 , 2024 2024 Citations: 33
Analyzing the dynamics of a charged rotating rigid body under constant torques TS Amer, HF El-Kafly, AH Elneklawy, AA Galal Scientific Reports 14 (1), 9839 , 2024 2024 Citations: 33
Analyzing the spatial motion of a rigid body subjected to constant body-fixed torques and gyrostatic moment TS Amer, HF El-Kafly, AH Elneklawy, AA Galal Scientific Reports 14 (1), 5390 , 2024 2024 Citations: 33
MOST CITED SCHOLAR PUBLICATIONS
Humanity's last exam L Phan, A Gatti, Z Han, N Li, J Hu, H Zhang, CBC Zhang, M Shaaban, ... arXiv preprint arXiv:2501.14249 , 2025 2025 Citations: 496
Asymptotic Solutions for the 3D Motion of Asymmetric Charged Gyrostatic Satellite Using Poincaré Small Parameter Technique TS Amer, A Alanazy, AH Elneklawy, WS Amer, HF El-Kafly Aerospace Science and Technology 168 (Part A), 110764 , 2025 2025 Citations: 56
Stability analysis of a rotating rigid body: The role of external and gyroscopic torques with energy dissipation TS Amer, HF El-Kafly, AH Elneklawy, AA Galal Journal of Low Frequency Noise, Vibration and Active Control 44 (3), 1502-1515 , 2025 2025 Citations: 56
Dynamical motion of a spacecraft containing a slug and influenced by a gyrostatic moment and constant torques TS Amer, AH Elneklawy, HF El-Kafly Journal of Low Frequency Noise, Vibration and Active Control 44 (3), 1708-1725 , 2025 2025 Citations: 50
Studying the influence of a gyrostatic moment on the motion of a charged rigid body containing a viscous incompressible liquid AA Galal, TS Amer, AH Elneklawy, HF El-Kafly The European Physical Journal Plus 138 (10), 959 , 2023 2023 Citations: 41
Modeling of the Euler-Poisson equations for rigid bodies in the context of the gyrostatic influences: an innovative methodology TS Amer, WS Amer, M Fakharany, AH Elneklawy, HF El-Kafly European Journal of Pure and Applied Mathematics 18 (1), 5712-5712 , 2025 2025 Citations: 33
Modeling analysis on the influence of the gyrostatic moment on the motion of a charged rigid body subjected to constant axial torque TS Amer, HF El-Kafly, AH Elneklawy, WS Amer Journal of Low Frequency Noise, Vibration and Active Control 43 (4), 1593-1610 , 2024 2024 Citations: 33
Analyzing the dynamics of a charged rotating rigid body under constant torques TS Amer, HF El-Kafly, AH Elneklawy, AA Galal Scientific Reports 14 (1), 9839 , 2024 2024 Citations: 33
Analyzing the spatial motion of a rigid body subjected to constant body-fixed torques and gyrostatic moment TS Amer, HF El-Kafly, AH Elneklawy, AA Galal Scientific Reports 14 (1), 5390 , 2024 2024 Citations: 33
Analysis of Euler’s equations for a symmetric rigid body subject to time-dependent gyrostatic torque TS Amer, AH Elneklawy, HF El-Kafly Journal of Low Frequency Noise, Vibration and Active Control 44 (2), 831-843 , 2025 2025 Citations: 31
A novel approach to solving Euler’s nonlinear equations for a 3DOF dynamical motion of a rigid body under gyrostatic and constant torques TS Amer, AH Elneklawy, HF El-Kafly Journal of Low Frequency Noise, Vibration and Active Control 44 (1), 111-129 , 2024 2024 Citations: 31
A novel study on the fourth first integral for the rotatory motion of an impacted charged rigid body by external torques TS Amer, A Alanazy, AH Elneklawy, WS Amer, HF El-Kafly Journal of Low Frequency Noise, Vibration and Active Control 44 (4), 1949-1960 , 2025 2025 Citations: 27
Damping-based attitude control of a gyrostatic satellite in resistive media AH Elneklawy, TS Amer, SA Elkilany, AS Abo Seliem, N Hegazy Journal of Applied and Computational Mechanics, e19528 , 2025 2025 Citations: 26
Application of Krylov–Bogoliubov–Mitropolski method to asymmetric gyrostatic 3D motion in multi-fields TS Amer, AH Elneklawy, HF El-Kafly Scientific Reports 15 (1), 42548 , 2025 2025 Citations: 21
Nonlinear dynamical behavior of a three-degree-of-freedom asymmetric rigid body under gyroscopic torque AH Elneklawy, TS Amer, A Alanazy, HF El-Kafly, AA Sallam Journal of Low Frequency Noise, Vibration and Active Control 45 (1), 150-177 , 2026 2026 Citations: 20
Nonlinear Dynamical Motion of a Nearly Spherical Gyrostat Containing a Spherical Slug Filled with a Viscous Liquid AH Elneklawy, TS Amer, HF El-Kafly Journal of Nonlinear Mathematical Physics 32 (1), 19 , 2025 2025 Citations: 17
Energy Decay in a Gyrostatically Influenced Rigid Body TS Amer, HF El-Kafly, AH Elneklawy, AA Galal Journal of Vibration Engineering & Technologies 14 (2), 93 , 2026 2026 Citations: 5
Semi-analytic solutions for finite-rotation attitude dynamics of gyrostatic rigid bodies TS Amer, RK Hussein, EA Ivanova, AH Elneklawy European Journal of Mechanics-A/Solids, 106131 , 2026 2026 Citations: 3
Rotational Dynamics and Stability of Gyrostatic Systems with Prescribed Internal Mass Motion: Asymptotic Methods and Spacecraft Attitude Control RK Hussein, MA Ibrahem, TS Amer, AH Elneklawy Mathematics 14 (9), 1463 , 2026 2026 Citations: 1
Optimization of asymmetric gyrostatic satellite kinematics in a resistive medium: A novel elliptic function solution AH Elneklawy, TS Amer, SA Elkilany, ASA Seliem, N Hegazy Scientific Reports 16 (1), 12212 , 2026 2026 Citations: 1