Article
Engineering, Civil
Ashraf M. Zenkour, Hela D. El-Shahrany
Summary: This article investigates the nonlinear hygrothermal effect on vibration analysis of a magnetostrictive viscoelastic laminated composite sandwich plate supported by two-parameter Pasternak's foundations. The study reveals that increasing the structural viscoelastic damping value reduces the natural frequency and deflection of the plate, while a higher hygrothermal factor leads to a longer suppression time for the plate's vibration.
ARCHIVES OF CIVIL AND MECHANICAL ENGINEERING
(2021)
Article
Computer Science, Interdisciplinary Applications
Ashraf M. Zenkour, Hela D. El-Shahrany
Summary: This article utilizes a quasi-3D trigonometric shear deformation plate theory to study the vibration response of an advanced composite plate, investigating methods for controlling and enhancing vibration damping. The numerical results reveal the significant factors influencing the vibration damping characteristics.
ENGINEERING WITH COMPUTERS
(2022)
Article
Mechanics
Ashraf M. Zenkour, Hela D. El-Shahrany
Summary: In this study, the vibration response and damping behavior of a multilayered composite plate with viscoelastic faces and homogenous core were analyzed, aiming to optimize the design of composite structural systems and accurately predict the vibration behavior under thermal/hygrothermal environments. The results showed that by combining passive and active strategies, the control systems of structural applications can be greatly improved.
MECHANICS BASED DESIGN OF STRUCTURES AND MACHINES
(2023)
Article
Materials Science, Composites
Ashraf M. Zenkour, Hela D. El-Shahrany
Summary: This article examines the hygrothermal forced vibration and damping analysis of a simply supported symmetric laminated composite plate with a homogeneous core and magnetostrictive layers using the exponential displacement model. Three types of hygrothermal environment distributions are investigated, with equations of motion developed for laminated rectangular plates subjected to hygrothermal loads and in-plane forces in x and y directions. The study results highlight the impact of various factors such as smart layer location, lamination schemes, mode number, aspect ratio, and temperature and moisture changes on the vibration response of the structure.
POLYMER COMPOSITES
(2021)
Article
Engineering, Mechanical
Ashraf M. Zenkour, Hela D. El-Shahrany
Summary: In this study, vibration analysis of adaptive sandwich plates under hygrothermal loads are performed. The influences of various parameters on the hygrothermal vibration characteristics are investigated, such as thickness ratio, aspect ratio, viscoelastic to magnetostrictive layer thickness ratio, modes, stiffness and damping coefficients, lamination schemes, magnitude of the feedback coefficient, location of the magnetostrictive layers, viscoelastic structural damping, temperature rise, and moisture concentration. The findings show that the vibration characteristics are sensitive to temperature and humidity concentrations. Considering these observations, the design of smart structural applications that can control vibration under such environmental conditions may be facilitated.
ACTA MECHANICA SINICA
(2023)
Article
Materials Science, Multidisciplinary
Ashraf M. Zenkour, Hela D. El-Shahrany
Summary: This study investigates the controlled motion of viscoelastic/fiber-reinforced/magnetostrictive/sandwich plates supported by visco-Pasternak foundations. The authors derive the governing dynamic system using Hamilton's principle and utilize a feedback control system to control the structural vibration. Numerical outcomes indicate that increasing the thickness ratio of the viscoelastic layer to the magnetostrictive layer improves system vibration control.
MECHANICS OF ADVANCED MATERIALS AND STRUCTURES
(2022)
Article
Mechanics
Ashraf M. Zenkour, Hela D. El-Shahrany
Summary: This article investigates the vibration characteristics of a magnetostrictive laminated composite sandwich plate with a viscoelastic core and faces on an elastic medium, analyzing the influence of various parameters on vibration properties. The findings can be utilized for developing adaptive structural applications and solutions to future smart structure problems.
COMPOSITE STRUCTURES
(2021)
Article
Mechanics
Ashraf M. Zenkour, Hela D. El-Shahrany
Summary: In this study, the vibration of a simply supported rectangular composite laminated plate with four actuating magnetostrictive layers was analyzed. The effects of temperature and moisture concentrations on the vibration behavior were investigated, indicating that increasing intelligent actuating layers improves the vibration damping process, but their position also plays a crucial role. Additionally, hygrothermal conditions reduce the ability of smart components to suppress structure vibration.
EUROPEAN JOURNAL OF MECHANICS A-SOLIDS
(2021)
Article
Computer Science, Interdisciplinary Applications
Mohamad W. Zaitoun, Abdelbaki Chikh, Abdelouahed Tounsi, Alfarabi Sharif, Mohammed A. Al-Osta, Salah U. Al-Dulaijan, Mesfer M. Al-Zahrani
Summary: This paper presents the solution for the free vibrational response of a functionally graded sandwich plate on a viscoelastic foundation under a hygrothermal environment load. The study shows that increasing the damping coefficient of the viscoelastic foundation enhances the plate's free vibrational response, with the degree of enhancement influenced by the hygrothermal environment.
ENGINEERING WITH COMPUTERS
(2023)
Article
Materials Science, Multidisciplinary
Ashraf M. Zenkour, Hela D. El-Shahrany
Summary: This study investigates the vibration of a laminated plate with a viscoelastic core and magnetostrictive layers, employing feedback and constant gain distributed control to dampen vibrations. Results show that the vibration suppression rate is significantly affected by the plate thickness, feedback control value, foundation constants, and viscoelastic structural damping.
JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES
(2022)
Article
Mechanics
Shahin Mohammadrezazadeh, Ali Asghar Jafari
Summary: This paper presents the nonlinear vibration control of laminated composite conical shells surrounded by elastic foundations through magnetostrictive layers. Velocity feedback control method is adopted to suppress the nonlinear vibration, and modified Galerkin method is used to obtain the nonlinear ordinary differential equation. The study investigates the asymptotical stability of the system around the zero equilibrium point and provides results for damping coefficients, fundamental linear frequency, and curves of amplitude versus nonlinear frequency and nonlinear frequency ratio for different parameter values.
COMPOSITE STRUCTURES
(2021)
Article
Mechanics
Michio Innami, Shinya Honda, Katsuhiko Sasaki, Yoshihiro Narita
Summary: An accurate and straightforward analytical method is proposed for the free vibration analysis of laminated composite rectangular plates with blended layers. The method is verified through numerical comparisons and tested in vibration optimization, showing that the introduction of blended layers is an effective approach to design the dynamic characteristics of laminated composite plates.
COMPOSITE STRUCTURES
(2021)
Article
Mechanics
Ashraf M. Zenkour, Hela D. El-Shahrany
Summary: This paper investigates the influence of the supporting system on the dynamic behavior of a smart laminated composite sandwich beam with functionally graded faces. Numerical examples are used to demonstrate the forced/free vibration response of the system and provide detailed illustrations of the variation in different geometrical parameters.
COMPOSITE STRUCTURES
(2022)
Article
Engineering, Civil
Hui Li, Zelin Li, Babak Safaei, Wanchong Rong, Wenyu Wang, Zhaoye Qin, Jian Xiong
Summary: An analytical model accounting for both material and geometric nonlinearities is proposed to predict the vibration behaviors of multiple viscoelastic-layered fiber metal laminated plates. Experimental validation shows that increasing base excitation amplitude leads to complex nonlinear vibration characteristics changes, influencing the natural frequencies and damping parameters.
THIN-WALLED STRUCTURES
(2021)
Article
Materials Science, Composites
Ashraf M. Zenkour, Hela D. El-Shahrany
Summary: This study investigates the vibration behavior of a laminated sandwich plate on a two-parameter elastic foundation with embedded magnetostrictive actuating layers and a homogeneous core. The plate is studied under three different types of hygrothermal environments, and system solutions are derived using Navier's technique. The analysis includes parametric effects on vibration characteristics such as elastic foundation, smart layer location, lamination schemes, and more, providing valuable insights for future studies in structural applications.
APPLIED COMPOSITE MATERIALS
(2022)
Article
Mechanics
Ashraf M. Zenkour
Summary: This comment paper highlights a serious error in the paper under review, specifically regarding incorrect displacements and erroneous shape functions.
MECHANICS BASED DESIGN OF STRUCTURES AND MACHINES
(2023)
Article
Mechanics
H. D. Chalak, A. M. Zenkour, Aman Garg
Summary: This study aims to analyze the free vibration of functionally graded single-walled carbon nanotube-reinforced composite (FG-CNTRC) beams under hygro-thermal conditions. The C-0 finite element-based higher-order zigzag theory is used, and five different graded beams are studied. The results show that stresses at higher mode of vibration are more affected by temperature or moisture concentration, and the stress distribution is widely influenced by the gradation law and temperature or moisture values.
MECHANICS BASED DESIGN OF STRUCTURES AND MACHINES
(2023)
Article
Mechanics
Ashraf M. Zenkour, Hela D. El-Shahrany
Summary: In this study, the vibration response and damping behavior of a multilayered composite plate with viscoelastic faces and homogenous core were analyzed, aiming to optimize the design of composite structural systems and accurately predict the vibration behavior under thermal/hygrothermal environments. The results showed that by combining passive and active strategies, the control systems of structural applications can be greatly improved.
MECHANICS BASED DESIGN OF STRUCTURES AND MACHINES
(2023)
Article
Mechanics
Nguyen Chi Tho, Do Van Thom, Pham Hong Cong, Ashraf M. Zenkour, Duc Hong Doan, Phung Van Minh
Summary: This study uses the third-order shear deformation theory and phase-field theory to model the free vibration response and static bending of laminated composite plates with just a core layer fracture. It integrates the finite element method with the phase-field theory to model the appearance of a fracture in a portion of the plate thickness. The results show surprising phenomena, such as minimal changes in crack length and plate properties, making it difficult to detect this kind of flaw.
COMPOSITE STRUCTURES
(2023)
Article
Mechanics
A. Garg, T. Mukhopadhyay, M. O. Belarbi, H. D. Chalak, A. Singh, A. M. Zenkour
Summary: Available shear deformation theories (SDTs) have their own merits and demerits. Among SDTs, first-order shear deformation theory (FSDT) and higher-order shear deformation theories (HSDT) are widely used for LCS beams analysis. However, they cannot predict the continuation of transverse shear stresses at interfaces across the thickness of the LCS beams. This study aims to transform the stress variations obtained from FSDT to 3D Elasticity solutions using Gaussian Process Regression (GPR) based surrogate model in order to predict the variation of transverse normal stresses across the thickness accurately and efficiently.
COMPOSITE STRUCTURES
(2023)
Article
Engineering, Mechanical
Ashraf M. Zenkour, Hela D. El-Shahrany
Summary: In this study, vibration analysis of adaptive sandwich plates under hygrothermal loads are performed. The influences of various parameters on the hygrothermal vibration characteristics are investigated, such as thickness ratio, aspect ratio, viscoelastic to magnetostrictive layer thickness ratio, modes, stiffness and damping coefficients, lamination schemes, magnitude of the feedback coefficient, location of the magnetostrictive layers, viscoelastic structural damping, temperature rise, and moisture concentration. The findings show that the vibration characteristics are sensitive to temperature and humidity concentrations. Considering these observations, the design of smart structural applications that can control vibration under such environmental conditions may be facilitated.
ACTA MECHANICA SINICA
(2023)
Article
Engineering, Multidisciplinary
Ashraf M. Zenkour, Hela D. El-Shahrany
Summary: In this study, smart Terfenol-D actuating layers are used to control composite viscoelastic beams with homogenous faces under thermal/hygrothermal environmental conditions. A three-parameter Kerr's foundation is employed to reduce system deflections. The cross-ply case of the structural layers is considered with simply supported conditions. The distributions of thermal/hygrothermal loadings are assumed to vary through the thickness direction of the beam. Analytical computations, tabular displays, and graphical illustrations are used to study the vibration damping process of the presented smart sandwich beam with important structure-dependent design parameters and environmental conditions variation.
JOURNAL OF ENGINEERING MATHEMATICS
(2023)
Article
Chemistry, Physical
Ashraf M. Zenkour, Tareq Saeed, Amal M. Aati
Summary: In this article, a mathematical analysis of thermoelastic skin tissue is conducted using a refined dual-phase-lag (DPL) thermal conduction theory that accounts for multiple time derivatives. The study examines the effects of mechanical clamping, ramp-type heating, and temperature distribution on the field variables of temperature, displacement, dilatation, and stress. The findings suggest that the refined DPL bioheat conduction model can predict temperature accurately and is consistent with existing generalized thermoelastic theories.
Article
Mathematics
Ashraf M. Zenkour, Tareq Saeed, Khadijah M. Alnefaie
Summary: Based on the Green-Lindsay generalized thermoelasticity theory, this paper proposes a new refined higher-order time-derivative thermoelasticity model. The model considers a thinner one-dimensional skin tissue with its inner surface free of traction and without any temperature increase. The heating of the skin tissue's bounding surface follows a ramp-type heating. The governing equations of the proposed model are derived, and the problem is solved using the Laplace transform and the inverse Laplace transform with Tzuo's method. Numerical results are obtained for the field quantities, and the current model is compared with two different theories of thermoelasticity to analyze the effects of various parameters on thermomechanical waves through the skin tissue.
Article
Mechanics
Quoc-Hoa Pham, Van Ke Tran, Trung Thanh Tran, Van Chinh Nguyen, Ashraf M. Zenkour
Summary: This article develops a novel finite element formulation based on nonlocal theory to analyze the vibration of viscoelastic orthotropic nanoplates resting on the variable viscoelastic foundation (VEF). The mechanical properties of the nanoplate are assumed to be viscoelastic orthotropic according to Kelvin's model. The variable VEF consists of two layers: a shear layer with constant stiffness, and the other layer is described as a system composed of alternating damping and springs, with variations only in the x-axis. Motion equations of the nanoplates are established using Hamilton's principle, a refined higher-order shear deformation plate theory (HSDT), and nonlocal theory. The results are verified through reliable publications, and factors influencing the vibration of orthotropic nanoplates resting on the variable VEF are discussed.
COMPOSITE STRUCTURES
(2023)
Article
Mechanics
B. Amieur, M. Djermane, A. M. Zenkour, F. Hammadi
Summary: One of the most important aspects in the dimensioning of structural calculations is the study of static or dynamic stability, which can be approached through different methods such as static buckling, parametric resonance, and dynamic buckling.The present work focuses on dynamic stability of functionally graded material shell structures, using dynamic buckling criteria. The objective is to determine the critical dynamic load of FG structures composite type in the dynamic case, using phase plane and motion equation criteria. Different mechanical properties are considered as continuous functions through-thickness direction, according to the volume fraction of the constituents using a simple power law distribution. The effects of variations in volume fractions and shell geometrical parameters are studied. Convergence tests and comparison studies are conducted to establish the efficiency of the proposed model.
MECHANICS BASED DESIGN OF STRUCTURES AND MACHINES
(2023)
Article
Mechanics
M. Ellali, M. Bouazza, A. M. Zenkour
Summary: This paper presents an analysis of wave propagation in functionally-graded (FG) nanoplates on a Winkler-Pasternak foundation. The investigation is conducted using nonlocal elasticity theory and a new four-unknown higher-order displacement theory with indeterminate integral terms. The frequency relations of FG nanoplates are obtained for different conditions using Hamilton's principle and Navier's method to solve an eigenvalue problem. The obtained results are compared with recent research on the frequency and phase velocity of wave propagation in FG nanoplates.
PHYSICAL MESOMECHANICS
(2023)
Article
Thermodynamics
Maryam H. Aljadani, Ashraf M. Zenkour
Summary: This paper aims to modify the generalized thermoelasticity theory of Lord-Shulman by incorporating higher-order time-derivative terms for accurate field variables. The refined theory is applied to study the effects of a magnetic field, a two-temperature parameter, and viscoelasticity on a thermoelastic medium with two temperatures. Analytical solutions are obtained and numerical data are presented using the normal mode technique. The results provide comparisons with existing literature and discuss the effects of various parameters.
CASE STUDIES IN THERMAL ENGINEERING
(2023)
Article
Engineering, Civil
Mokhtar Ellali, Mokhtar Bouazz, Ashraf M. Zenkour
Summary: The objective of this work is to study the wave propagation of an FGM plate with temperature-dependent material properties using a new integral inverse shear model. A new model based on a high-order theory field of displacement is proposed, which includes indeterminate integral variables and inverse co-tangential functions for the representation of shear stress. The effects of temperature and volume fraction distributions on wave propagation of the FGM plate are investigated, and the results are compared with previous research on dispersion and phase velocity curves.
GEOMECHANICS AND ENGINEERING
(2023)