Higher-order Shear Deformation Theory Research Articles

Three-dimensional thermomechanical wave propagation analysis of sandwich nanoplate with graphene-reinforced foam core and magneto-electro-elastic face layers using nonlocal strain gradient elasticity theory

This article investigates the propagation of bending, longitudinal, and shear waves in a smart sandwich nanoplate with a graphene platelet (GPL)-reinforced foam core and magneto-electro-elastic (MEE) surface layers using sinusoidal higher-order shear deformation theory (SHSDT). The suggested nanoplate is comprised of a Ti–6Al–4V foam core placed between MEE surface layers. The MEE surface layers are composed of a volumetric combination of cobalt-ferrite (CoFe2O4) and barium-titanate (BaTiO3). The foam core and MEE face layers’ material characteristics are temperature dependent. In this study, three different core types are considered: metallic solid core (Type-I), GPL-reinforced solid core (Type-II) and GPL-reinforced foam core (Type-III), as well as three different foam distributions: symmetrical foam I (S-Foam I), symmetrical foam II (S-Foam II) and uniform foam (U-Foam). To derive the nanoplate's equations of motion and determine the system response, Hamilton's principle and Navier's method are employed. The effects of various parameters such as the wave number, nonlocal parameter, foam void coefficient and distribution pattern, GPL volume fraction, and thermal, electric, and magnetic charges, on the phase velocity and wave frequency are investigated via analytical calculations. The findings of the research indicate that the 3-D wave propagation characteristics of the sandwich nanoplate can be considerably modified or tuned with respect to external loads and material parameters. Thus, the proposed sandwich structure is expected to provide important contributions to radar stealth applications, protection of nanoelectromechanical devices from high frequency and temperature environments, advancement of smart nanoelectromechanical sensors characterized by lightweight and temperature sensitivity and wearable health equipment applications.

A study on graphene-reinforced magneto-electro-elastic laminated nanoplate's thermomechanical vibration behaviour based on a higher-order plate theory

Sandwich nanostructures incorporating piezoelectric and magneto-electro-elastic properties have emerged as promising candidates for next-generation smart devices and composites. Due to their exceptional design, fabrication, and energy conversion capabilities, these structures are extensively utilised as sensors and actuators in nano-electromechanical systems. Accordingly, in this article, the free vibration behaviour of a multifunctional laminated (MFL) nanoplate with piezoelectric PZT5-H and magnetostrictive CoFe2O4 (cobalt-ferrite) face layers and a graphene-reinforced core layer is investigated by applying a higher-order sinusoidal shear deformation theory (HSDT). In addition, two different material cases consisting of Ti6Al4V and ZrO2 materials and two foam models, uniform and symmetric, are considered for the foam core layer. Hamilton's principle is used to obtain the plate's governing equations. Navier's solution approach is utilised to get the natural frequencies of the laminated nanoplate under thermal load and electric and magnetic fields. A parametric study is performed to determine the effects of volumetric graphene content, the foam model and its pore ratio, face/core material content, external electric and magnetic potential, and thermal load on the free vibration response of the MFL nanoplate. The obtained numerical results can be a reference point for future research on layered porous MEE structures, especially for micro/nano-sized systems.

Numerical analysis of uncertain frequency of rotating composites using NURBS-based isogeometric HSDT approach: Rim-driven configuration

This study delves into the impact of material and fabrication uncertainties on the natural frequencies of rim-driven rotating structures. Utilizing a higher-order shear deformation theory (HSDT), an isogeometric analysis (IGA) model predicts these frequencies. Sensitivity analysis via a radial basis function network (RBFN) model, validated with Monte Carlo simulation, highlights parameter influence. Parametric investigations unveil sensitivity patterns and influential parameters. Employing a stochastic approach, the study compares the effects of random material properties on the free vibration response of rotating and non-rotating plates. Additionally, the RBFN-based surrogate model assesses reliability parameters concerning resonance failure in rim-driven rotating composite structures.

An analytical study of thermal environment’s effect on the free vibration of FGM double curved FG shells

The main objectif of this work is to examine the thermal environment’s effect of on the free vibration of double curvature shells made of functionally graded materials. A new mathematical model based on higher order shear deformation theory, is developed to incorporate the influence of dependent and independent thermal stresses, which can be uniform, linear, nonlinear, or sinusoidal on the mechanical properties of the double curvature shell. Two material couples, ( S i 3 N 4 / SUS 304 , ZrO 2 /Ti‐6Al‐4V ) , are considered as progressive materials, accounting for temperature-dependent and temperature-independent heat conduction and material properties in the thickness direction. The temperature field is assumed to be uniform across the shell surface but varies only in the thickness direction. The accuracy of the analytical results is validated by comparing them with existing literature results for functionally graded material (FGM) shells with infinite radii under dependent and independent temperature conditions. The study aims to demonstrate the thermal effects on material composition, as well as various specific geometric shapes such as plates, cylinders, spheres and ellipses and how different temperature laws influence the frequencies of vibrating double curvature FGM shells. Both existing theories accurately predict temperature-independent and temperature-dependent vibration responses of the shells. By verifying and comparing the results with the literature, a better agreement is achieved, thereby paving the way for further research in this field.

An isogeometric analysis of solar panels with a bio-inspired substrate

We in this paper propose a high-performance design using bio-inspired metamaterials for multilayered perovskite solar cell (MPSC) plates. The static bending and free vibrational responses of the newly designed MPSC panels with the presence of the triply periodic minimal surface (TPMS) substrate are subsequently investigated numerically. The displacements of the present plate model are then approximated by five-variable higher-order shear deformation theories (HSDTs). The weak forms are established for both the static bending and free vibration problems and subsequently derive the discrete forms using the NURBS-based isogeometric approach. To enhance the operational efficiency of solar panels in challenging environments, we integrate advanced lightweight architectures based on bio-inspired TPMS structures as a substrate layer into the original solar panel design. In this research, three widely employed TPMS structures: Primitive, Gyroid, and I-graph and Wrapped Package-graph (IWP), are examined in conjunction with two functional grading patterns implemented through the thickness direction. For the first time, the static bending performance of MPSC plates integrated into a TPMS-based substrate layer and subjected to wind pressure as well as thermal conditions is comprehensively studied. In addition, the influence of several significant factors on the free vibration behavior of MPSC plates is also elucidated. The findings show a promising and intriguing design avenue, particularly in the application of high-performance metamaterials to address contemporary challenges in renewable energy usage and environmental protection.

Vibration and aeroelastic instability analysis in GPL-porous multi-layered beam with the rotation effect

This research studies the vibrations and instability of a rotating three-layer beam under aerodynamic forces consisting of two functionally graded (FG) composite surfaces and a porous intermediate layer. Linear poroelasticity theory is used for modeling the porous layer while Young’s modulus and density vary along the thickness. Equivalent coefficients of the graphene nanoplatelets-reinforced composite (GPLs) are extracted by modified Halpin-Tsai theory, according to five different configurations. The equations of motion in the GPL-porous multi-layered beam are derived using the Euler–Bernoulli beam (EBB), Timoshenko beam (TB), and Reddy’s higher-order shear deformation theory (HSDT) theories, as well as the energy method and Hamilton’s principle. The most important results show the effect of reinforcements and their different configurations, porosity and its distribution, speed of rotation on natural frequency, critical flutter point, and loss factor for a GPL-porous multi-layered beam. The unique properties of GPL-reinforced porous materials facilitate the design of components capable of effectively managing dynamic loads and resisting aeroelastic instabilities. This results in more efficient, reliable, and durable systems across various industries.

Measurement of phase velocity in the functionally graded concrete systems via improved higher-order shear deformation theory

The measurement of phase velocity (PV) in concrete systems is critically important for civil engineers as it provides essential insights into the material properties and structural integrity of concrete. PV, which refers to the speed at which a wave phase propagates through a medium, is directly related to the stiffness and density of the material. By accurately measuring PV, civil engineers can assess the quality and homogeneity of concrete, detect potential flaws, and predict the material’s behavior under various load conditions. This information is crucial for ensuring the safety and durability of concrete structures, from bridges and buildings to pavements and dams. Moreover, understanding PV helps in the optimization of mix designs and the development of new, advanced concrete materials, ultimately leading to more resilient and cost-effective construction practices. For this issue, in this work, for the first time, the measurement of PV in the concrete doubly curved panel reinforced by graphene oxide powders (GOPs) via improved higher-order shear deformation theory is presented. Hamilton’s principle and analytical method are used for extracting and solving the higher-order equations. Finally, some recommendations for improving the efficiency and stability of the concrete structures are presented for related engineering industries. The findings underscore the potential of combining state-of-the-art theoretical models with cutting-edge material reinforcements to push the boundaries of structural engineering and material performance.

An intelligent computational iBCMO-DNN algorithm for stochastic thermal buckling analysis of functionally graded porous microplates using modified strain gradient theory

The authors propose an intelligent computational method using the deep feedforward neural network integrated with an improved balance composite motion optimization algorithm to formulate a so-called iBCMO-DNN for solving the stochastic thermal buckling problems of functionally graded porous microplates. In the present approach, the deterministic behaviors of the functionally graded porous microplates were firstly analyzed by the combination of a unified higher-order shear deformation theory, modified strain gradient theory, and Ritz-type series solutions, and then stochastic responses under uncertainty of material properties are obtained by the iBCMO-DNN algorithm. The deep neural network with the long short-term memory model is used as a surrogate method to replace the time-consuming computational model, while the improved balance composite motion optimization is used to search for the optimal solutions. The obtained numerical results for various boundary conditions, uncertainty parameters, and three types of temperature distribution indicated that the proposed method achieves its accuracy and effectiveness in predicting stochastic thermal buckling of the functionally graded porous microplates. The improved balance composite motion optimization algorithm demonstrates a computational time ∼1.7 times faster than its predecessor. Furthermore, integrating a deep neural network into the improved algorithm reduces computational time to about 2/5 compared to the method without it.

The role of nonlocality on low and high frequency behaviors of functionally graded sandwich nanoplates

AbstractThe role of nonlocality on low and high frequency behaviors and modes of the functionally graded (FG) sandwich nanoplates is investigated in this study for the first time using simple nonlocal higher‐order shear deformation theory (HSDT). The simple HSDT consists of only four unknowns in its equation of the displacement field. The nonlocal elasticity theory is used to consider the small‐scale effects on the behaviors of the nanoplates. The governing equations of motion are established by applying Hamilton's principle, then Navier's solution technique is employed to solve these equations to achieve the free vibration behaviors of the FG sandwich nanoplates. The vibrations of the nanoplates under both low and high frequency conditions are investigated, but the high frequency vibration of the nanoplates is discussed extensively. The influences of the geometrical dimensions, material gradient index, and nonlocal parameter on the high frequency vibration of the FG nanoplates are also considered and discussed comprehensively.

A size-dependent electro-mechanical buckling analysis of flexoelectric cylindrical nanoshells

In this paper, a buckling analysis for flexoelectric cylindrical nanoshells under axial compression is performed by considering the higher-order shear deformation theory and non-uniform pre-buckling deformation. Size-dependent critical buckling stresses and buckling mode shapes are obtained by the Galerkin's method with newly proposed displacement functions. Numerical results are compared with existing solutions and excellent agreements are observed. Furthermore, a comprehensive parametric study of boundary conditions, geometrical parameters and applied electric voltage is carried out to reveal the influence of flexoelectric effect on the size-dependent buckling characteristics of flexoelectric cylindrical nanoshells.

Vibration analysis of sandwich functionally graded material plate with cut-outs using artificial neural network technique

In the present article, the effect of geometric discontinuities on the vibrational response of porous sandwich functionally graded material (SFGM) plates with double FGM facesheets has been investigated using the artificial neural network (ANN) technique. Generalized governing equations for the SFGM plate have been derived based on nonpolynomial based higher-order shear deformation theory (HSDT). Geometric discontinuities have been incorporated in terms of cut-outs in the SFGM plates. The FGM layers integrate a porosity model, while the core layer is considered a ceramic layer within the SFGM plate structure. Further, a C° continuous isoparametric finite element formulation with a four-noded, isoparametric quadrilateral element with seven degrees of freedom (DOFs) per node has been employed to accomplish the results. The accuracy of the present results has been demonstrated through convergence and validation studies. A comprehensive study has been carried out to investigate the influence of volume fraction index, even and uneven porosity distribution and cut-outs on the frequency parameter of SFGM plates. However, the finite element method (FEM) is computationally challenging. Therefore, the motivation behind adopting ANN technique to develop a predictive model for reasonable accuracy with less computational time. The ANN technique is proposed to predict the NDFP of the SFGM plate using cut-outs under various conditions using numerical simulation datasets. An optimised ANN model has been developed with an architecture of (6–5–10–5–1), exhibits best performance based on mean error value, which accurately predicts the Non-Dimensional Frequency Parameter (NDFP) of the SFGM plate.

Isogeometric Analysis of Laminated and Carbon Nanotube Reinforced Composite Stiffened Plate Using Higher Order Shear Deformation Theory

Isogeometric Analysis of Laminated and Carbon Nanotube Reinforced Composite Stiffened Plate Using Higher Order Shear Deformation Theory

Conical-Shaped Shells of Non-Uniform Thickness Vibration Analysis Using Higher-Order Shear Deformation Theory

Conical-Shaped Shells of Non-Uniform Thickness Vibration Analysis Using Higher-Order Shear Deformation Theory

Data-driven uncertainty quantification and sensitivity studies in free vibration behavior of bio-inspired helicoidal laminated composite cylindrical shells

The uncertainty in the ply orientation of bio-inspired helicoidal laminated composite cylindrical shells is quantified. The frequencies obtained from the higher-order shear deformation theory are trained to formulate a surrogate model in the multi-output Gaussian Process Regression algorithm framework, and the stochastic analysis is then carried out using the Monte Carlo simulation method. For simply supported and clamped shells, uncertainties in the top and bottom-most layers widely affect the free vibration behavior of the shells compared to the inner-most or central layers, whereas for cantilever shells, opposite trend is observed. The inclusion of noise widely affects the free vibration behavior.

Thermal buckling analysis of a new type of rectangular FG sandwich plates using a new higher-order shear deformation theory

This article presents a novel higher-order shear deformation Theory to investigate the thermal buckling behavior of a new type of functionally graded material (FGM) sandwich structure. The study focuses on a specific configuration of rectangular FGM sandwich plate, consisting of FGM face layers and FGM core layer subjected to temperature gradients varying linearly and non-linearly across the thickness. By employing the principle of virtual work, the governing equations are derived, involving only four unknown functions. The Navier procedure is then utilized to obtain closed-form solutions. In this study, the material properties and thermal expansion coefficient of the two face layers of the sandwich plate are assumed to vary in the thickness direction according to a simple power-law distribution. In contrast, the core layer is assumed to have an exponential variation along the thickness direction. The critical thermal buckling is influenced by various factors, including the thickness, and aspect ratios of the sandwich plate, the gradient index, the type of loading, and the type of sandwich plate. The effects of these variables on the critical buckling temperature are thoroughly examined and analyzed.

On the vibration responses of orthotropic laminated cylindrical panels with non-uniform porosity distributions using higher-order shear deformation theory

The present study investigates free vibration analysis of cylindrical panels made of porous orthotropic layers. Porous material properties are modeled using uniform and two non-uniform porosity distribution patterns through the thickness. The theoretical formulations are expressed based on the higher-order shear deformation theory. The equations of motion of laminated cylindrical panels are established by performing Hamilton’s principle. These fundamental partial differential equations are solved analytically for the laminated cylindrical panels, which are simply supported on all edges. Galerkin’s solution procedure is applied to obtain the natural frequency equation. The natural frequencies are compared to results in the literature to verify the obtained frequency equation. Afterward, novel parametric studies are developed to discuss the influence of porosity parameters, porosity distribution patterns, geometrical parameters, orthotropy, and lamination sequences on the free vibration response of porous laminated cylindrical panels.

Temperature-dependent thermal buckling and free vibration behavior of smart sandwich nanoplates with auxetic core and magneto-electro-elastic face layers

This article addresses the thermomechanical thermal buckling and free vibration response of a novel smart sandwich nanoplate based on a sinusoidal higher-order shear deformation theory (SHSDT) with a stretching effect. In the proposed sandwich nanoplate, an auxetic core layer with a negative Poisson’s ratio made of Ti-6Al-4V is sandwiched between Ti-6Al-4V rim layers and magneto-electro-elastic (MEE) face layers. The MEE face layers are homogenous volumetric mixtures of cobalt ferrite (CoFe2O4) and barium titanate (BaTiO3). The mechanical and thermal material properties of the auxetic core and MEE face layers are temperature-dependent. Using Hamilton’s principle, governing equations are constructed. To characterize the size-dependent behavior of the nanoplate, governing equations are adapted with the nonlocal strain gradient theory (NSGT). By applying the principles of Navier’s technique, closed-form solutions are obtained. Parametric simulations are carried out to examine the effects of auxetic core parameters, temperature-dependent material properties, nonlocal parameters, electric, magnetic, and thermal loads on the free vibration and thermal buckling behavior of the nanoplate. According to the simulation results, it is determined that the auxetic core parameters, temperature-dependent material properties, and nonlocal factors significantly affect the thermomechanical behavior of the nanoplate. The outcomes of this investigation are expected to contribute to the advancement of smart nano-electromechanical systems, transducers, and nanosensors characterized by lightweight, exceptional structural integrity and temperature sensitivity. Also, the auxetic core with a negative Poisson’s ratio provides a metamaterial feature, and thanks to this feature, the proposed model has the potential to be used as an invisibility technology in sonar and radar-hiding applications.

Free vibration analysis of CNT reinforced plates using higher order shear deformation theory

With the stringent requirements of lightweight and high stiffness in space technology and spacecraft, the research on frequency characters of carbon nanotubes (CNTs) reinforced structures is particularly urgent. In this paper, based on the Reissner-Mindlin higher-order shear deformation theory (HSDT), a vibration model for a CNT functionally graded (FG) plate is developed, and influences of the reinforcements distribution form, reinforcement volume fractions, and various boundary conditions of the structure are considered in this established model. Subsequently, the model’s convergence test was presented first with a rectangular plate structure. Finally, the vibration characteristics and modal shapes of the CNT-FG plate structure are carried out by using this model.

Effect of bi-directional material gradation on thermo-mechanical bending response of metal-ceramic FGM sandwich plates using inverse trigonometric shear deformation theory

PurposeThe purpose of this study is to investigate the bending analysis of metal (Ti-6Al-4V)-ceramic (ZrO2) functionally graded material (FGM) sandwich plate with material property gradation along length and thickness direction under thermo-mechanical loading using inverse trigonometric shear deformation theory (ITSDT). FGM sandwich plate with a ceramic core and continuous variation of material properties has been modelled using Voigt’s micro-mechanical model following the power law distribution method. The impact of bi-directional gradation of material properties over the bending response of FGM plate under thermo-mechanical loading has been investigated in this work.Design/methodology/approachIn this study, gradation of material properties for FGM plates is considered along length and thickness directions using Voigt’s micromechanical model following the power law distribution method. This type of FGM is called bi-directional FGMs (BDFGM). Mechanical and thermal properties of BDFGM sandwich plates are considered temperature-dependent in the present study. ITSDT is a non-polynomial shear deformation theory which requires a smaller number of field variables for modelling of displacement function in comparison to poly-nominal shear deformation theories which lead to a reduction in the complexity of the problem. In the present study, ITSDT has been utilized to obtain the governing equations for thermo-mechanical bending of simply supported uni-directional FGM (UDFGM) and BDFGM sandwich plates. Analytical solution for bending analysis of rectangular UDFGM and BDFGM sandwich plates has been carried out using Hamilton’s principle.FindingsThe bending response of the BDFGM sandwich plate under thermo-mechanical loading has been analysed and discussed. The present study shows that centre deflection, normal stress and shear stress are significantly influenced by temperature-dependent material properties, bi-directional gradation exponents along length and thickness directions, geometrical parameters, sandwich plate layer thickness, etc. The present investigation also reveals that bi-directional FGM sandwich plates can be designed to obtain thermo-mechanical bending response with an appropriate selection of gradation exponents along length and thickness direction. Non-dimensional centre deflection of BDFGM sandwich plates decreases with increasing gradation exponents in length and thickness directions. However, the non-dimensional centre deflection of BDFGM sandwich plates increases with increasing temperature differences.Originality/valueFor the first time, the FGM sandwich plate with the bi-directional gradation of material properties has been considered to investigate the bending response under thermo-mechanical loading. In the literature, various polynomial shear deformation theories like first-order shear deformation theory (FSDT), third-order shear deformation theory (TSDT) and higher-order shear deformation theory (HSDT) have been utilized to obtain the governing equation for bending response under thermo-mechanical loading; however, non-polynomial shear deformation theory like ITSDT has been used for the first time to obtain the governing equation to investigate the bending response of BDFGM. The impact of bi-directional gradation and temperature-dependent material properties over centre deflection, normal stress and shear stress has been analysed and discussed.

A new higher-order shear deformation theory for flutter instability of a hybrid sandwich panel resting on a viscoelastic foundation

Magnetorheological elastomers (MREs) are smart materials characterized by their ability to adjust mechanical properties through the manipulation of applied magnetic fields, facilitating rapid and reversible tunability. The incorporation of reinforcing fibers introduces distinctive materials termed Magnetorheological Elastomer Composites (MRECs), combining tunability with enhanced rigidity. This study delves into the flutter analysis of a sandwich panel with a mid-layer composed of laminated MRECs and face sheets composed of functionally graded materials (FGMs) featuring porosity. The sandwich panel is situated on a viscoelastic foundation and exposed to a supersonic air current. Employing a higher-order (hyperbolic) shear deformation theory (HSDT), the displacement field of the sandwich plate is estimated. This selection eliminates the requirement for shear correction factors. The mechanical characteristics of the three sheets are determined using the Halpin-Tsai micromechanical method and the rule of mixture. The First-order Piston theory is employed to evaluate the effect of aerodynamic pressure and airflow damping on the sandwich panel. The derivation of the motion equation is achieved through Hamilton's principle. In order to solve the motion equation of the structure, the Finite Element Method (FEM) is utilized. The investigation systematically explores the influence of diverse parameters on the flutter boundary of the sandwich panel.