Journal of Computational Applied Mechanics
https://jcamech.ut.ac.ir/
Journal of Computational Applied Mechanicsendaily1Mon, 01 Apr 2024 00:00:00 +0330Mon, 01 Apr 2024 00:00:00 +0330Analyzing the Thermoelastic Responses of Biological Tissue Exposed to Thermal Shock Utilizing a Three-Phase Lag Theory
https://jcamech.ut.ac.ir/article_94311.html
This article presents a mathematical analysis of thermoelastic skin tissue using an improved thermal conduction theory known as the refined three-phase-lag (TPL) theory. By accounting for the effects of multiple time derivatives, this advanced model provides a more accurate representation of how skin tissue behaves under different temperature conditions. The thin skin tissue is considered to have mechanically clamped surfaces, which are assumed to be one-dimensional. Furthermore, the skin tissue experiences a thermal shock load on its outer surface while maintaining a constant temperature on its inner surface. The proposed model has led to the derivation of certain generalized thermoelasticity theories in previous studies. The Laplace transform and its associated numerical inversion method are employed to calculate the distributions of temperature, displacement, dilatation, and stress in the system. The obtained outcomes are explicitly depicted to analyze the significant influences on the distributions of the field variables. These findings shed light on the behavior of skin tissue when subjected to a particular temperature distribution at the boundary condition, enhancing our knowledge in this area.Elastostatic behaviour of functionally graded porous beams: novel Kuhn Tucker conditions with R program for mathematical computing
https://jcamech.ut.ac.ir/article_95804.html
Pores affect functionally graded materials. Further characteristics may be added if pores expand from the surface to the interior. Functionally graded porous beam (FGPB) bending response is analyzed using a specific shear shape function that accounts for both uniform and uneven porosity distributions. Power law changes the material characteristics of FGPBs with uniform and uneven porosity distributions along length and thickness. In order to determine the maximum transverse deflections, axial stresses, transverse shear stresses, and normal stresses in simply-supported and clamped-clamped beams, numerical calculations are performed with various gradation exponents, aspect ratios (L/h), and porosity levels (both even and uneven). The obtained results are compared with earlier investigations and justified.Efficient Kinematic model for Stability Analysis of Imperfect Functionally Graded Sandwich Plates with Ceramic middle layer and Varied Boundary Edges
https://jcamech.ut.ac.ir/article_95899.html
The present paper introduces an efficient higher-order theory to analyze the stability behavior of porous functionally graded sandwich plates (FGSPs) resting on various boundary conditions. The FG sandwich plate comprises two porous FG layers, face sheets, and a ceramic core. The material properties in the FGM layers are assumed to change across the thickness direction according to the power-law distribution. To satisfy the requirement of transverse shear stresses vanishing at the top and bottom surfaces of the FGSP, a trigonometric shear deformation theory containing four variables in the displacement field with indeterminate integral terms is used, and the principle of virtual work is applied to describe the governing equation than it solved by Navier solution method for simply supported boundaries. However, an analytical solution for FGSPs under different boundary conditions is obtained by employing a new shape function, and numerical results are presented. Furthermore, validation results show an excellent agreement between the proposed theory and those given in the literature. In contrast, the influence of several geometric and mechanical parameters, such as power-law index, side-to-thickness, aspect ratio, porosity distribution, various boundary conditions, loading type, and different scheme configurations on the critical buckling, is demonstrated in the details used in a parametric study.Vibration Behaviour of Shear Deformable Laminated Plates Composed of Non-Homogeneous Layers
https://jcamech.ut.ac.ir/article_96127.html
The free vibration behavior of laminated plates consisting of non-homogenous orthotropic layers is presented. First, the mechanical properties of laminated plates composed of non-homogenous (NH) orthotropic layers are modelled. After establishing the basic relations of laminated plates within shear deformation theory (SDT), governing equations are derived in the framework of Donnell type plate theory. The solution of the governing equations is carried out by the Galerkin method and the analytical expression is found for the linear frequency of plates composed of non-homogenous orthotropic layers. Finally, the influences of various factors such as shear stresses, non-homogeneity, number and arrangement of layers on the frequency of rectangular plates are examined.Effect of Porosity on the Static Response of Rotating and Non-Rotating Porous Timoshenko Beam
https://jcamech.ut.ac.ir/article_96242.html
This study aims to determine the effect of porosity on the static response of rotating and non-rotating porous beam. Timoshenko beam theory has been used and the governing equation has been solved via B-spline collocation technique. The material distribution is a function of power law along the height of the beam, even and uneven distribution of porosity has been considered. The parameter such as power index, porosity coefficient and rotational speed have been varied. Deflection and stress variation has been plotted for even and uneven distribution of porosity for relative study. The outcome reveals that effect of even distribution of porosity is higher than uneven porosity. The study also shows that rotation of the beam has significant impact on the deflection and stress distribution of the beam and also reveals that porous beams can be used where high strength and low stiffness is required.Fuzzy logic-based variable impedance control for a bilateral teleoperation system under time delay
https://jcamech.ut.ac.ir/article_95918.html
In a delayed master-slave teleoperation system, if the slave robot interacts with a delicate and sensitive environment, it is essential to control the slave-environment interactions. Variable impedance control has been proposed as a useful method for this aim in the literature. However, changing the impedance parameters based on the system requirements imposes a complex process in the controller design. To address this issue, we propose a variable impedance control strategy for the slave side, where the impedance variables are changed using fuzzy logic. This is carried out based on the environment destruction threshold&mdash;defined based on the contact force and the velocity of the slave robot&mdash;and system stability range. The proposed method is simulated in MATLAB&rsquo;s Simulink considering telesurgery conditions and soft tissue environment under an unknown and varying time delay. Simulation results show that the proposed method maintains the velocity of the slave robot and the environment force in the desired interval and performs better in keeping the environment safe compared to the constant-coefficient impedance control.Material Nonlinear Static Analysis of Axially Functionally Graded Porous Bar Elements
https://jcamech.ut.ac.ir/article_96101.html
This investigation presents material nonlinear analysis of a cantilever bar element made of functionally graded material with porosity properties. The material properties of bar element are considered as changing though axial direction based on the Power-Law distribution and uniform porosity distribution. The stress-strain relation of the material is considered as a nonlinear property according to a Power-Law function. The cantilever bar element is subjected to a point load at the free end. In order to obtain more realistic solution for the nonlinear problem and axially material distribution, nonlinear finite element method is used. In the obtaining of finite element equations, the virtual work principle is used and, after linearization step, the tangent stiffness matrix and residual vector are obtained. In the nonlinear solution process, the incremental force method is implemented and, each load step, the nonlinear equations are solved by using the Newton-Raphson iteration method. In the numerical results, effects of material nonlinearity parameters, porosity coefficients, material distribution parameter and aspect ratios on nonlinear static deflections of the bar are presented and discussed. The obtained results show that the material nonlinear behaviour of the bar element is considerably affected with porosity and material graduation.From Data to Stability: A Novel Approach for Controlling Unknown Linear Time-Invariant Systems with Performance Enhancement
https://jcamech.ut.ac.ir/article_96094.html
A novel data-driven control methodology is introduced in this paper, specifically designed for unknown linear time-invariant systems. Schur stability is established through the application of Linear Matrix Inequality (LMI) conditions, and system performance is improved by leveraging the concept of D-stability. Stability and performance are ensured by incorporating LMI features, with reliance solely on a finite set of collected data, eliminating the necessity for system model identification. Hence, the original performance mapping problem undergoes a transformation into a stability issue, incorporating modified system matrices. Then, the stability condition is formulated within the framework of LMI. The effectiveness of our approach is exemplified through two specific examples, highlighting the significant and impactful results obtained. These examples serve to showcase the practical application and outcomes of our methodology within the defined scope, providing a clear demonstration of its performance and efficacy in addressing relevant scenarios.Variational principle for Schrödinger-KdV system with the M-fractional derivatives
https://jcamech.ut.ac.ir/article_96445.html
The variational theory is an inextricable part of both continuum mechanics and physics, and plays an important role in mathematics and nonlinear science, however it is difficult to find a variational formulation for a nonlinear system, and it is more difficult for a fractional differential system. This paper is to search for a variational formulation for the Schr&ouml;dinger-KdV system with M-fractional derivatives. The fractional complex transformation is used to convert the system into a traditional differential system, and the semi-inverse method is further applied to establish a needed variational principle.Nonlinear Dynamic Stability Analysis of Axially Moving CNTRC Piezoelectric Viscoelastic Nano/Micro Plate Based on MCST
https://jcamech.ut.ac.ir/article_95384.html
Analyzing the nonlinear dynamic stability of axially moving carbon nanotube reinforced composite (CNTRC) piezoelectric viscoelastic nano/micro plate under time dependent harmonic biaxial loading is the purpose of the present study. The nano/micro plate is made from Polyvinylidene Fluoride (PVDF). It moves in the positive direction of the x-axis at a constant velocity and supported by a nonlinear viscoelastic piezoelectric foundation (Zinc Oxide). A viscoelastic material is assumed in the Kelvin-Voigt model. Nano/micro plate is exposed to electric potential, 2D magnetic field and uniform thermal gradient. Maxwell's relations are used to integrate magnetic field effects. The nano/micro plate as well as smart foundation are subjected to electric potential in thickness direction. The effective elastic properties are estimated using the Eshelby-Mori-Tanaka approach. Von-K&aacute;rm&aacute;n's theory provides the basis for the nonlinear strain-displacement relationship. According to various shear deformation plate theories, a novel formulation is presented that incorporates surface stress effects via Gurtin-Murdoch elasticity theory. A modified couple stress theory (MCST) is used in order to consider small scale parameter. It is possible to derive the governing equations by using the energy method and Hamilton's principle. An analysis is conducted using Galerkin procedure and finally the incremental harmonic balance method (IHBM) to obtain the dynamic instability region (DIR). Among the parameters that will be examined are small-scale parameter, alternating and direct applied voltages, magnetic field intensity, surface effects as well as axially moving speed. The results demonstrate that increasing the axial speed of the nano/micro plate causes the system to become more unstable. As a result, if the smart foundation is considered, in addition to increasing the excitation frequency, the area of the instability zone will also decrease by at least 50%. It is estimated that in a static state (not moving), the area of the instability zone is reduced by more than 70%.Vibration analysis of the Gamma-Ray element in the ELI-NP interaction chamber (IC)
https://jcamech.ut.ac.ir/article_96470.html
The influence of vibrations on the position of the target in the interaction chamber of the ELI-NP facility represents an important element in any experiment with gamma beam rays. Also, several detection systems are provided around the interaction chamber for tracking the nuclear reactions that occur inside the interaction chamber. They are fixed with very high precision in relation to the interaction chamber. In addition to tracking the gamma ray beam, it must to know with great precision the position of the sample holder and of these detectors placed in laboratory. The precision required for a gamma-ray experiment is determined by the size of the studied material. If there is enough target material, then the precision is not important, but if we have a very small amount of material, then precision becomes significant. For a common experiment, accuracy is considered satisfactory for a value of 2&mu;m. The paper analyzes the influence of anthropogenic and natural vibrations on the position of the target, located at the end of a guide beam.Deflection, buckling and vibration analyses for a sandwich nanocomposite structure with foam core reinforced with GPLs and SMAs based on TSDBT
https://jcamech.ut.ac.ir/article_96649.html
The purpose of this research is to investigate deflection, buckling and vibration for a five-layer sandwich nanocomposite beam, with reinforcements of graphene platelets (GPLs) and shape memory alloys (SMAs), and a foam core. To predict the behavior of the beam, theoretical formulations are derived based on the third order shear deformation beam theory (TSDBT). In order to check the validity and accuracy of the present work, the obtained results are compared with the results of other works and there is a good compatibility between them. It is concluded from this research that by using foam as the core, the weight of the structure is reduced, and also, the use of GPLs and SMAs as a reinforcement in the beam structure increases the stiffness and the equivalent elasticity modulus, so the ratio of strength to the weight of the structure increases. As a result of which the deflection decreases, the critical buckling load and the natural vibration frequencies of the beam increase. For example, it can be seen in the results that by increasing the volume fraction of GPL from 0 to 0.03, the deflection of the beam decreases by 44% and the first natural frequency of vibration and the critical buckling load increase by 31% and 79%, respectively.A novel quasi-3D refined HSDT for static bending analysis of porous functionally graded Plates
https://jcamech.ut.ac.ir/article_96209.html
In this paper a quasi-three-dimensional (3D) refined using a novel higher-order shear deformation theory is developed to examine the static bending with two different type porosity distribution of porous for advanced composite plates such as functionally graded plates. In this present theory, the number of unknowns and governing equations is reduced, takes into account the thickness stretching effect into transverse displacement, bending and shear, using a new shape function. The used plate theory approach satisfies the zero traction boundary conditions on the surfaces of the plate without using shear correction factor and the transverse shear strain and shear stress have a parabolic distribution across the thickness of the plates. The virtual work principle is used to obtain the equilibrium equations. An analytical approach based on the Navier solution is employed to obtain the solution for static bending of simply supported FGM plates. The proposed theory shows a good agreement for static bending of FGM plates with other literature results has been instituted of advanced composite plates. Numerical results are presented to show the effect of the material distribution, the power-law FG plates, the geometrical parameters and the porosity on the deflections and stresses of FG plates.Numerical Simulation of Laminar Flow of a Non-Newtonian Bentonite Solution in a Horizontal Pipe
https://jcamech.ut.ac.ir/article_96340.html
The present study constitutes a notable contribution to enhancing our understanding of the behavior exhibited by non-Newtonian fluids. The purpose of the study involves conducting numerical simulations that elucidate the laminar flow dynamics within a horizontal pipe. The investigated flowing medium consists of bentonite suspensions with varying concentrations. The rheological behavior of the fluid is accurately described using the Herschel-Bulkley model, a pseudo-plastic representation. The results obtained through this research have helped to meticulously analyze the influence of fluctuations in the rheological index n on the following flow key parameters: pressure drop, velocity, and coefficient of friction within the pipe. This analysis covers a range of generalized Reynolds numbers, all the values of which correspond to the laminar flow regime. The meticulous study of the flow parameters reveals a compelling alignment between the simulation results and the experimental measurements, which underscores the validity of the study's findings.Analyzing the Buckling Behavior of In-plane Bidirectional Functionally Graded Porous Plates
https://jcamech.ut.ac.ir/article_96454.html
The spacecraft and space shuttles demand novel engineering materials to meet the required properties. This can be accomplished by altering the material properties in more than one direction. The introduction of inplane bidirectional functionally graded materials with porosity are expected to exhibit these properties. This paper presents the buckling analses of inplane bidirectional (2-D) functionally graded porous plates (IBFGPPs) considering uniform porosity distribution in uni-axial and bi-axial compression. The effective modulus of elasticity of the material is varied in in x-and y-axes by employing the rule of mixtures. The higherorder theory used for the study of buckling response meets the nullity requirements at plate&rsquo;s upper and lower surface and derived the equations of motion thru Lagrange equations. The displacement functions are formulated in simple algebraic polynomials, incorporating admissible functions to satisfy the simply supported conditions in both axial and transverse directions. The components of admissible functions are derived by Pascal&rsquo;s triangle. Accurateness of this theory is judged by comparing it to existing numerical data in the literature. The effect of thickness ratio&rsquo;s (a/h), aspect ratio&rsquo;s (b/a), exponents (&zeta;_1and &zeta;_2) in &eta;_1 and &eta;_2-direction, and the porosity on the buckling response of IBFGPPs are examined comprehensively. The numerical findings provided here serve as reference solutions for evaluating diverse plate theories and for comparing them against results obtained through alternative analytical and finite element techniques. From the obtained results, it can be inferred that the proposed theory facilitates the assessing of buckling tendencies of in-plane bi-directional porous FG plates produced through sintering process and could be deemed as a pivotal in the process of optimizing the design of the IBFGPPs.Thermal Radiation and Shape Factor Effects on Electro-magnetohydrodynamic Tri-hybrid Williamson Liquid Flow Around a Cylinder
https://jcamech.ut.ac.ir/article_96455.html
Industries such as film manufacturing and polymer solution processing benefit from the Williamson fluid model because it more accurately characterizes the behaviour of pseudo-plastic fluids by including maximum and minimum viscosities. This work presents a numerical simulation that investigates the thermal behaviour of tri-hybrid Williamson nanoliquid flow around a cylindrical surface. The primary focus of the study is to examine the influence of thermal radiation, electro-magnetohydrodynamic (EMHD), and the shape factor of nanomaterials on the physical quantities of energy transfer-related. Through the utilization of the hybrid linearization spectral method, the mathematical model that governs the problem is solved. The credibility and reliability of the obtained results are firmly established through verification against existing findings. The main results of this study reveal a remarkable decrease in heat transfer improvement for the tri-hybrid nanofluid as the Weissenberg number increases. The skin friction is shown to exhibit a clear increasing trend with the radiation coefficient, while the augmentation of the volume fraction factor or electrical factor demonstrates a discernible amelioration in velocity profiles. With increasing volume fraction, using Al2O3(hexahedron) - TiO2(tetrahedron) - Cu(lamina) / H2O raises the Nusselt number by 0.02&ndash;5% while decreasing skin friction by 1.3 - 9% compared with using Al2O3(sphere)-TiO2(sphere)-Cu(sphere)/H2OThe onset of Casson fluid convection in a permeable medium layer produced by purely inner heating with magnetic field
https://jcamech.ut.ac.ir/article_96462.html
In this inspection, the control of the magnetic power on the onset of Casson fluid convection formed by purely inner warming in a porous medium layer is examined. The modified Darcy model is employed to designate the rheological arrival of Casson liquid flow in a porous matrix. Two types of thermal boundaries are exploited, namely, type (I) both isothermal and type (II) lower insulated and top isothermal boundaries. Using the linear stability inspection and Galerkin technique, the approximate analytical solution and numerical solution correct to one decimal place are offered. It is detected that for type (I) boundary conditions, the convective wave concentrates in the upper layer if it occurs, whereas for type (II) boundary conditions, it emphases in the whole layer. The magnetic Chandrasekhar number postpones the convection movement while the Casson constraint accelerates it. The facet of the convective cells drops with enhancing the magnetic strength and the Casson constraint. In the absenteeism of magnetic field, the Casson constraint has no regulation on the dimension of convective cells. It is also found that the presented analytical result with two term Galerkin process has overall 5% error, while with one term Galerkin process the error was overall 19%.Free Convection from a One End Closed Vertical Pipe with Annular Fins: A Computational Study
https://jcamech.ut.ac.ir/article_96469.html
Cylindrical objects in heat transfer applications have always taken the spotlight due to their compact nature and better surface area-to-volume ratio over their cuboid counterparts. Despite this advantage, fins have been used to enhance the heat transfer properties of such geometries. This study involves one such geometry where the top of the cylinder is open to the surrounding atmosphere and the cylinder is fitted with annular fins of different sizes and spacing. The k-&epsilon; model is used to simulate the turbulent cases along with a density-based solver. The cylinder is modeled to be a heat source with a constant temperature of 350 K and the surrounding atmosphere being air at 300 K. Nusselt number and effectiveness of the fins were calculated and analyzed. The heat flow rate experienced a maximum increase of 50% when the number of fins is raised from S/d 0.9 to S/d 0.3. The maximum effectiveness occurs at Ra = 1011, with a value of 4.44 observed for S/d of 0.3 and d/D of 0.25. The maximum values for effectiveness are observed at lower d/D and S/d values.Coupled loading hygro-thermo-mechanical Effect on the stability of imperfect functionally graded sandwich plates
https://jcamech.ut.ac.ir/article_96595.html
In this research study, the hygro-thermo-mechanical responses of simply supported porous FG sandwich plates resting on a variable elastic foundation are studied by mean of a new height order shear deformation theory. The present model satisfies the nullity conditions of the shear stresses on the upper and lower surfaces of the FG plate and without using shear correction factors. The distribution of the properties of the material through the thickness of the sandwich plate is assumed to have a distribution according to a function of the power law, while the core is assumed to be purely ceramic. The derivation of the stability equations is obtained based on the principle of virtual works. The hygro-thermal loading is considered to have a uniform, linear and non-linear variation across the thickness of the plate. To verify the accuracy of the current model, a comparison was made with other authors of the literature. The effects of the hygro-thermo-mechanical loading, the porosity, the parameters of the elastic foundation &laquo; kw and kg &raquo;, the thickness ratio &laquo; a/h &raquo;, the aspect ratio &laquo; a/b &raquo; and the material index &laquo; k &raquo; on the critical buckling load of the FG plate are examined.Comparative in silico analysis of CHIR99021, Azakenpaullone and Tricantin interactions with GSK3β, a key protein in stem cell fates
https://jcamech.ut.ac.ir/article_96610.html
Glycogen Synthase Kinase 3&beta; (GSK3&beta;) is a multifunctional serine/threonine-protein kinase that serves as a pivotal regulator of various human pluripotent stem cell (hPSCs) functions, including self-renewal, adhesion, survival, and differentiation in addition to have an effect on motility of sperm. Despite advancement in understanding the critical roles of GSK3&beta; inhibition in various stem cell functions, the exact molecular basis of its inactivation using various small-molecule inhibitors remains poorly understood. Investigating the mechanistic details of the actions of inhibitors targeting GSK3 proteins, such as CHIR99021, Azakenpaullone, and Tricantin, could be extremely beneficial for improving novel defined stem cell culture systems and cancer research. The present study aimed to predict the binding mode of the aforementioned ligands with GSK3&beta;, by molecular docking and metadynamic simulation, and compare the three-dimensional structure of the inactive conformation of GSK3&beta; in the presence of three inhibitors. Also, the pharmacokinetic or ADMET properties of ligands, such as Lipinski's rule of five violations for drug-likeness, QPlog S, QPlog K, and bioactivity scoring, were predicted. The analysis of protein stability revealed that in the absence of inhibitors, the GSK3&beta; has higher flexibility, while in the presence of CHIR and AZA, the rate of flexibility of most protein regions, especially the envelope area, decreased. It was found that though all small molecules are capable of facilitating the inhibition of GSK3&beta; protein, but the flexibility of protein is a bit higher for CHIR than those for other two ligands.Estimation of Elastic and Piezoelectric Properties of Short Piezo Fuzzy Fiber Reinforced Composite Using Method of Cells Micromechanics Approach
https://jcamech.ut.ac.ir/article_96658.html
Piezoelectric fibers are being widely used in the development of devices such as sensors, actuators, energy harvesting equipment, and in instruments related to biomedical engineering. Piezoelectric (PZT) fibers with radially grown carbon nanotubes (CNTs) on their surface when used as homogenous fiber in the preparation of a composite lamina is found to exhibit some enhanced elastic and piezo electric properties. The short piezoelectric fibers with radially grown CNTs which is known as piezo fuzzy fiber (PFF) are horizontally embedded in the polymer matrix to form short piezo fuzzy fiber reinforced composite (SPFFRC) lamina and the characterized mechanical properties estimated by method of cells (MOC) approach and the same has been compared with the conventional Mori-Tanaka (MT) method. The effect of waviness which are inherent to the CNTs on the overall properties have been estimated and are reported in the present study. Also, the significance of CNT orientation on the final elastic and piezo electric properties of SPFFRCs have been displayed in detail in the present study. The orientation of CNTs is vital and the results of the study show that when the CNTs are oriented transverse to the base fiber direction, the elastic properties are enhanced while the piezoelectric properties showed no or negligible effect on the orientation of CNTs. Also, the straight CNTs showed better performance in electric properties of SPFFRC while the performance slightly reduced with increase in waviness of CNTs. However, the effective elastic properties showed an increasing trend with increase in CNT waviness and hence, for the better use of the proposed SPFFRC as materials for actuator or sensor, the SPFFRC with wavy CNTs may be preferred since the waviness is inherent characteristic of CNTs and the waviness of CNTs has minimal effect on piezoelectric properties but has significant effect on the elastic properties.Contribution study on factors impacting the vibration behavior of functionally graded nanoplates
https://jcamech.ut.ac.ir/article_96797.html
This comprehensive study investigates the behavior of functionally graded (FG) nanoplates, providing insights into their characteristics and important design considerations. By examining factors such as homogenization models (Voigt Reuss, LRVE, and Tamura), volume fraction laws (power-law model, Viola-Tornabene four-parameter model, trigonometric model), eigenmode, aspect ratios, index material, and small-scale length parameters, the study evaluates their influence on the natural frequency response of simply supported nanoplates. A novel twisting function is introduced and its accuracy in predicting natural frequencies in FG square nanoplates is rigorously validated through numerical comparisons with existing literature. The findings obtained from this research offer valuable guidance for optimizing the design of FG nanoplates and significantly contribute to advancing our understanding of their dynamics and practical applications.Stability analysis of functionally graded graphene platelets-reinforced nanocomposite shells
https://jcamech.ut.ac.ir/article_96798.html
Investigating the stability of cylindrical shells made of composite materials is a valuable subject in mechanical engineering due to their plethora of usages across various industries. In the present investigation, the stability behavior of graphene platelets (GPLs) enhanced nanocomposite shells is methodically examined. The calculation of the composite material's properties is conducted by utilizing the modified rule of mixtures approach. Additionally, a first-order shear deformation theory is employed in conjunction with the principle of virtual work to establish the essential differential equations for the analysis. The solution to these equations is achieved by applying Galarkin&rsquo;s method, which is renowned for its accuracy and efficiency in resolving both static and dynamic problems. Verification of the formulated model is done by comparing the results with existing literature. Novel findings are presented showing the variation in buckling behavior of GPL-reinforced nanocomposite shells for assorted circumferential wave numbers. Moreover, the study delves into the impact of variations in GPLs' weight fraction, length and radius to thickness ratios, and the presence of an elastic medium on the critical buckling loads of these advanced composite shell structures.Static stability analysis of FG thick plate supported by three parameters foundation under general boundary conditions
https://jcamech.ut.ac.ir/article_96916.html
In this paper, an analytical solution for exploring the buckling characteristics of functionally graded (FG) plate is presented based on a quasi-3D shear deformation theory. It is considered that the plate is subjected to different types of in-plane compressive load. The FG plate is placed on three-parameter foundation Winkler-Pasternak-Kerr. The overall material properties of FG plate are assumed to be varied across the thickness and are estimated through the Voigt micromechanical model. The governing equations are obtained on the base of the quasi-3D deformation theory that contain undetermined integral forms and involves only four unknowns to derive. Equations of motion are derived from the principal of virtual work and the analytical solution is used to determine the critical buckling loads. By the discussion of numerical examples and the comparison with those of the reports in the literature, the convergence and the reliability of the present approach are validated. Finally, the parametric investigations of the in-plane buckling are carried out, including the influence of boundary conditions, elastic foundation, plate geometric parameters and power law index. The results reveal that the critical buckling loads are strongly influenced by several parameters such as boundary conditions, elastic foundation parameters and geometric shape of the plate.An investigation into the numerical analysis of refined higher order shear deformation theory for frequency responses of two-directional functionally graded taper beams
https://jcamech.ut.ac.ir/article_96924.html
For the aircraft and space shuttles to have the right properties, they need new engineering materials. Changing the qualities of the material in more than one direction is one way to do this. These features should be seen in in-plane, bi-directional functionally graded materials. This study examines the vibration behavior of a two-directional functionally graded taper beam (TDFGTB) with uniform load distribution. The analysis uses a refined higher-order shear deformation theory, Lagrange equations, and the displacement functions are formulated in simple algebraic polynomials incorporating admissible functions to satisfy the boundary conditions in both directions with the help of a Ritz-type solution. The components of admissible functions are derived from Pascal&rsquo;s triangle. The study also examines the influence of taper ratios, aspect ratios, and gradation exponents on the vibration response. The results provide a benchmark for assessing beam theories and are crucial for optimizing the design of TDFGTBs.Numerical investigation on unsteady compressible flow of viscous fluid with convection under the effect of Joule heating
https://jcamech.ut.ac.ir/article_97043.html
The study of compressible flow plays a fundamental role in the design of heat exchangers at high temperature and pressure. Compressible flow is used to design the aerodynamic structure, engines, and high-speed vehicles. In view of these utilities, this paper is deliberated to acquire the analysis of the unsteady compressible flow of a viscous fluid through an inclined asymmetric channel with thermal effects. Special attention is paid to convective heat transfer with impact of viscous dissipation, source/sink, and joule heating effects. In addition, thermal flow is analyzed through slip boundary conditions. The current problem is modeled through the laws of energy, momentum, and mass with the help of a fluid&rsquo;s response towards compression. As a result, the coupled nonlinear partial differential equations are obtained, which are investigated through a well-known numerical approach, the explicit finite difference method. The study examines impact of several parameters on the flow rate, velocity, and temperature with the help of graphical representations. The behavior of flow rate is intended to change with time.