Article
Mechanics
Chang Tao, Ting Dai
Summary: This study investigates the postbuckling behavior of sandwich cylindrical shell panels with a graphene platelet reinforced functionally graded porous core under various loads for the first time. Utilizing a combination of NURBS-based isogeometric analysis and the modified arc-length method, the study demonstrates nonlinear load-deflection responses and captures different types of instability. Parametric studies show the influences of various factors on the load-deflection behavior of the panels.
COMPOSITE STRUCTURES
(2021)
Article
Mechanics
Yuewu Wang, Wei Zhang
Summary: In this study, the thermal buckling and postbuckling behaviors of graphene platelet (GPL) reinforced porous nanocomposite beams with temperature-dependent material properties were investigated. The effective properties of nanocomposites were determined using the Halpin-Tsai micromechanics model, extended rule of mixture, and open-cell metal foam model. The governing equations for thermal buckling and postbuckling problems were derived using a high order shear deformation theory with von Karman nonlinearity. To describe the end restraints of the beams, numerically stable admissible functions were constructed using the Gram-Schmidt procedure. The critical buckling temperatures were obtained by solving an eigenvalue equation without geometric nonlinearity, while an iterative methodology was used to find the temperature-dependent thermal postbuckling paths. Extensive numerical study showed that the temperature-dependency of material properties significantly influenced the thermal buckling/postbuckling behaviors of GPL-reinforced porous beams. Dispersing more GPLs on the upper and lower surfaces and fabricating more internal pores near the central portion of the beams improved the thermal instability-resistance capability of composite structures.
COMPOSITE STRUCTURES
(2022)
Article
Mechanics
Haiyang Yu, Feng Liu
Summary: This study investigates the snap-through phenomenon in a thermally pre-buckled or post-buckled reinforced composite beam. The governing equations of the beam are obtained using the first order shear deformation beam theory and the von-Karman type of kinematic assumptions. The non-linear equations governing the beam's response to thermal and mechanical loads are solved using the conventional Ritz method with Chebyshev polynomials. The study finds that factors such as temperature change, weight fraction of graphene platelets (GPLs), distribution pattern of GPLs, and boundary conditions significantly influence the limit loads and intensity of the snap-through phenomenon.
MECHANICS BASED DESIGN OF STRUCTURES AND MACHINES
(2023)
Article
Engineering, Civil
H. Pham-Tan, Chien H. Thai, P. Phung-Van
Summary: In this article, the free vibration, bending, and transient analyses of the porous metal foam plate using isogeometric analysis are investigated. The effects of different parameters on the frequencies, deflections, and dynamic responses of the plate are studied. Key findings can be given for manufacturing metal foam structures.
THIN-WALLED STRUCTURES
(2022)
Article
Engineering, Civil
P. Phung-Van, Qui X. Lieu, A. J. M. Ferreira, Chien H. Thai
Summary: This study presents an effective and simple approach based on RPT and IGA for bending and vibration analyses of FG GPLRC nanoplates. The reinforcement of GPLs can dramatically improve the stiffness of nanoplates, with rich GPLs at the bottom and top considered the most effective for reinforcement.
THIN-WALLED STRUCTURES
(2021)
Article
Construction & Building Technology
Mohammad Mashhour, Mohammad Reza Barati, Hossein Shahverdi
Summary: In this study, the flutter characteristics of porous nanocomposite cylindrical shells, reinforced with graphene platelets (GPLs) in supersonic airflow, were investigated. Both uniform and non-uniform distributions for GPLs and porosities were considered. The effective material properties were determined using the Halpin-Tsai micromechanical model. A cylindrical shell formulation considering supersonic airflow was developed, and the governing equations were solved using Galerkin's method to obtain frequency-pressure plots. It was found that the flutter points of the shell were influenced by the amount, distribution of porosities and GPLs, as well as the shell's geometrical parameters.
STEEL AND COMPOSITE STRUCTURES
(2023)
Article
Engineering, Civil
Vuong Nguyen Van Do, Chin-Hyung Lee
Summary: This study focused on examining the buckling and postbuckling behavior of laminated composite plates with graphene platelets (GPLs) under various thermal loadings using the IGA method. The results demonstrated the successful tracking of the nonlinear buckling and postbuckling path of nanocomposite plates, while further investigating the impacts of various factors.
ENGINEERING STRUCTURES
(2021)
Article
Engineering, Aerospace
Nam V. Nguyen, Duc-Huynh Phan
Summary: This study investigates the dynamic instability behavior of advanced sandwich plate structures subjected to periodic in-plane compressive loads using a computational approach based on a refined quasi-3D plate theory and NURBS-based isogeometric analysis. The findings provide new insights into the dynamic instability behavior of sandwich plates and suggest careful evaluation of the thickness stretching effect for moderate to thick plate structures.
AEROSPACE SCIENCE AND TECHNOLOGY
(2023)
Article
Materials Science, Multidisciplinary
Fan Yang, Xianlai Song, Xuyang Wang, Weilin Yang
Summary: In this paper, the thermal postbuckling behavior of porous piezoelectric nanobeams is investigated using the first-order shear deformation beam theory. The effects of surface elasticity and pore distribution pattern on the mechanical properties are analyzed. The results show that the surface effect increases the effective elastic modulus and critical load, while reducing the thermal postbuckling conformations and induced charge. Additionally, it is found that a reasonable pore distribution pattern can improve the mechanical properties.
MECHANICS OF ADVANCED MATERIALS AND STRUCTURES
(2023)
Article
Mechanics
Quoc-Hoa Pham, Phu-Cuong Nguyen
Summary: This paper analyzes the dynamic stability behaviors of porous functionally graded microplates using a refined plate theory and modified couple stress theory within an isogeometric analysis framework. The effects of microstructure are captured by employing only one material length scale parameter. Numerical investigations are carried out to study the influences of factors such as porosity coefficient and distribution, material length scale, and load factors on dynamic instability characteristics.
COMPOSITE STRUCTURES
(2022)
Article
Engineering, Mechanical
Fahed Mohd, Mohammad Talha
Summary: This paper investigates the influence of material uncertainties on the postbuckling behavior of functionally graded porous beams reinforced with graphene platelets under thermal conditions using the stochastic finite element method. The study considers temperature-dependent and temperature-independent material properties and uses the Halpin-Tsai micromechanics model and Voigt's rule of mixture to estimate the homogenized material properties. A higher-order shear deformation theory with Von-Karman type geometric non-linearity is employed for the postbuckling analysis. The developed C-0 finite element model and direct iterative procedure are used to solve the non-linear governing equations. The results show that material uncertainties significantly affect the postbuckling response of FG-GPLRC porous beams.
ACTA MECHANICA SINICA
(2023)
Article
Mechanics
Feifei Zhao, Hong Bao, Jianfeng Liu, Kexiang Li
Summary: An accurate and effective reconstruction method for multilayered composite and sandwich laminated beam deformation field is proposed in this study. The method uses inverse finite element and Refine Zigzag Theory to improve reconstruction accuracy. Experimental results demonstrate superior accuracy and potential applicability of the proposed approach for accurate shape prediction.
COMPOSITE STRUCTURES
(2021)
Article
Engineering, Mechanical
Lu Lu, Gui-Lin She, Xingming Guo
Summary: Graphene reinforced composites have shown remarkable mechanical properties, and this study focuses on the size-dependent postbuckling behavior of functionally graded graphene platelets reinforced composite microtubes. Different distribution patterns of graphene reinforcements were considered, and it was found that the microstructure effect is significant when the outer radius of the microtube is comparable to the material length scale parameter. The study provides theoretical guidelines for optimal design and safety assessment of graphene reinforced composite tubular structures.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2021)
Article
Mathematics
Youssef Boutahar, Nadhir Lebaal, David Bassir
Summary: A refined beam theory incorporating thickness-stretching was proposed to analyze the bending vibratory behavior of thick FG beams. By reducing the number of unknowns and governing equations, the theory accurately predicts the vibratory responses of FG beams in terms of material composition, geometry, and shear deformation, showing the impact of normal deformation which is often neglected in other beam theories.
Article
Engineering, Civil
Arash Davoudvand, Hadi Arvin, Yaser Kiani
Summary: This paper examines the backbone curves of nanocomposite beams reinforced with graphene platelet (GPL) on elastic foundation under temperature increment. The study uses mathematical modeling and iterative calculations to determine the nonlinear natural frequency and the corresponding backbone curve of the nanocomposite beam. The results show that the weight fraction and distribution pattern of GPL have an influence on the mechanical behavior of the nanocomposite beam, and the temperature increment further affects the backbone curves.
INTERNATIONAL JOURNAL OF STRUCTURAL STABILITY AND DYNAMICS
(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)
Article
Mechanics
Rania Tantawy, Ashraf M. Zenkour
Summary: This paper investigates the impact of porosity on rotating functionally graded piezoelectric (FGP) variable-thickness annular disk. The porous disk is subject to electromagnetic, thermal, and mechanical loadings. Material coefficients are graded using a power law in the radial direction. The results show that porosity significantly affects the temperature, stresses, and displacement of the disk, highlighting its importance in engineering mechanical design.
JOURNAL OF APPLIED AND COMPUTATIONAL MECHANICS
(2023)
