Editorial

Transient responses of functionally graded double curved shallow shells with temperature-dependent material properties in thermal environment

The purpose of the paper is to develop an analytical investigation on free vibration of a simply supported functionally graded (FG) doubly curved shell panels resting on elastic foundation in thermal environment. Heat conduction and temperature-dependent material properties are both taken into account. The temperature field considered is assumed to be a uniform distribution over the shell surface and varied in the thickness direction only. Material properties are assumed to be temperature dependent and graded in the thickness direction according to a simple power law distribution in terms of the volume fractions of the constituents. Based on the first-order shear deformation theory and applying the Hamilton’s principle, governing equations of motion are derived. The results of the study are compared with the available published literature. The numerical results obtained reveal that the material volume fraction index, geometrical parameters and temperature change have significant effects on natural frequencies of the FG doubly curved shell panels.

Nonlinear buckling of eccentrically stiffened functionally graded toroidal shell segments under torsional load surrounded by elastic foundation in thermal environment

This study focuses on free vibration analysis of functionally graded material (FGM) plates supported by Winkler–Pasternak elastic foundation in thermal environment using element-free Galerkin (EFG) meshless method. Plate kinematics depend on first-order shear deformation theory. Uniform, linear, and nonlinear temperature variations through the thickness direction are considered, along with the temperature-dependent material properties. The numerical outcomes obtained from EFG method are compared with those available in the published literature to validate the proposed method’s accuracy. An artificial neural network (ANN) model that can easily predict the natural frequencies of the plate is constructed from the EFG method outcomes. Further, the effect of foundation parameters, power law index, thickness ratio, temperature variations, and different boundary conditions are investigated; results show that these significantly influence the vibration response of FGM plates supported by the elastic foundation. Increasing the temperature of FGM plates supported by the Winkler–Pasternack foundation causes a decrease in the dimensionless fundamental natural frequency, and the uniform temperature influence is greater than that of linear and nonlinear temperature variation. The proposed EFG-ANN prediction model saves approximately 98.80% computation time when predicting the natural frequency with an accuracy of approximately 98.76% compared to that by EFG meshless method alone.

Nonlinear postbuckling of an eccentrically stiffened thin FGM plate resting on elastic foundations in thermal environments

Nonlinear vibration of stiffened multilayer FG cylindrical shells with spiral stiffeners rested on damping and elastic foundation in thermal environment

Nonlinear bending and postbuckling of FGM cylindrical panels subjected to combined loadings and resting on elastic foundations in thermal environments

This paper deals with nonlinear vibration analysis of functionally graded plate resting on Pasternak elastic foundation in thermal environment. A mathematical model is developed based on higher-order shear deformation theory using Green-Lagrange type nonlinearity. The model includes all the nonlinear terms to obtain a general form and to present the original flexure of the plate. The material properties are considered as temperature dependent and graded along thickness direction obeying a simple power law distribution in terms of volume fraction of the constituents. The compression/traction free condition is employed to obtain the simplified model with seven parameters instead of nine parameters. The plate model has been discretized into C0 eight noded quadratic elements with seven degrees of freedom per node. The governing equation of the functionally graded plate has been derived using Hamilton's principle and is solved using direct iterative method. The present model is validated by comparing the obtained results with those published in the literature. The effects of volume fraction index, aspect ratio, thickness ratio, support conditions, elastic foundation modulus and temperature on the nonlinear frequencies of the functionally graded plates are discussed. It has been found that the intermediate material property does not necessarily give intermediate nonlinear frequency

Postbuckling analysis of axially-loaded functionally graded cylindrical shells in thermal environments

This article investigates the nonlinear stability of eccentrically stiffened moderately thick plates made of functionally graded materials (FGM) subjected to in-plane compressive, thermo-mechanical loads. The equilibrium and compatibility equations for the moderately thick plates are derived by using the first-order shear deformation theory of plates, taking into account both the geometrical nonlinearity in the von Karman sense and initial geometrical imperfections, temperature-dependent properties with Pasternak type elastic foundations. By applying the Galerkin method and using a stress function, the effects of material and geometrical properties, temperature-dependent material properties, elastic foundations, boundary conditions, and eccentric stiffeners on the buckling and post-buckling loading capacity of the eccentrically stiffened moderately thick FGM plates in thermal environments are analyzed and discussed.

Transient response of rotating laminated functionally graded cylindrical shells in thermal environment

Nonlinear analysis on dynamic buckling of eccentrically stiffened functionally graded material toroidal shell segment surrounded by elastic foundations in thermal environment and under time-dependent torsional loads

Thermoelastic response of CNT reinforced cylindrical panel resting on elastic foundation using theory of elasticity

This paper presents an analytical approach to postbuckling behaviors of functionally graded multilayer nanocomposite plates reinforced by a low content of graphene platelets (GPLs) using the first order shear deformation theory, stress function and von Karman-type nonlinear kinematics and include the effect of an initial geometric imperfection. The weight fraction of GPL nano fillers is assumed to be constant in each individual GPL-reinforced composite (GPLRC). The modified Halpin-Tsai micromechanics model that takes into account the GPL geometry effect is adopted to estimate the effective Young’s modulus of GPLRC layers. The plate is assumed to resting on Pasternak foundation model and subjected to mechanical and thermal loads. The results show the influences of the GPL distribution pattern, weight fraction, geometry, elastic foundations, mechanical and temperature loads on the postbuckling behaviors of FG multilayer GPLRC plates.
 Keywords: Postbuckling; Graphene nanocomposite plate; First order shear deformation plate theory.
 References
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Nonlinear vibrations of composite plates on an elastic foundation in thermal environments are presented in this study. Graphite/epoxy is selected as the plate material. The properties of composite material are assumed to be temperature-dependent. Nonlinear free vibrations of laminated composite plates are investigated in the fully clamped boundary conditions. The classical finite element method is used and a specially prepared computer code is written in the Matlab software. Vibrations of the spring supported laminated composite plate are directly influenced by the boundary conditions and dimensions of plate.In this study, generated graphical values reveal that foundation stiffness and temperature have significant effects on the linear and nonlinear frequencies of composite plates.