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

Functionally graded materials is a new material for thermal protection in the aerospace field. It is extremely important to study the temperature and stress changes in the thermal environment to ensure the normal operation of the spacecraft and the safety of crews. In this paper, ABAQUS is used to perform sequential thermal coupling and full thermal coupling analysis. The temperature variation and mechanical properties of functionally graded cylindrical shells in thermal environment under temperature and force field and temperature field interacts with force field are studied. Based on the first law of thermoelasticity and thermodynamics, the three-dimensional stress and energy equations of functionally graded cylindrical shells in thermal environment are derived. The example shows that the temperature variation law and mechanical characteristics of the two types of thermo-mechanical coupling analysis are almost the same. The temperature value results of the sequential thermal-mechanical coupling analysis are the same as the results of the full thermal coupling, but the stress value results are lower than the results of the full thermal coupling.

Nonlinear resonance behavior of functionally graded cylindrical shells in thermal environments

Editorial

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

The nonlinear vibration behavior of the spiral stiffened multilayer functionally graded (SSMFG) cylindrical shells with initial imperfection exposed to axial parametric and external excitation in the thermal environment is presented in this paper using a semi-analytical method. The distribution of temperature and material constitutive of the stiffeners along the direction of thickness is assumed. The cylindrical shell consists of three layers, the interior and exterior layer is respectively rich metal and ceramic, and the middle layer is functionally graded material (FGM). Using the smeared stiffeners technique, von Kármán equations, and the Galerkin method, the nonlinear vibration problem has been solved. Then, utilizing the multiple scales method, the nonlinear vibration behavior of the system is examined. The resonant case, including internal parametric resonance among three modes and subharmonic resonance of order one-half, is considered. The results show that although the trend of all figures is approximately like together, but the maximum amplitude vibration of the internal SSMFG cylindrical shell with the angle of stiffeners and the external SSMFG cylindrical shell with the angle of stiffeners is more than others.

On the finite element analysis of functionally graded sandwich curved beams via a new refined higher order shear deformation theory

Three-dimensional free vibration analyses of functionally graded laminated shells under thermal environment by a hierarchical quadrature element method

A layerwise finite element formulation for free vibration analysis of functionally graded sandwich shells

This paper uses a quasi-3D refined shear deformation plate theory to investigate the buckling response of supported functionally graded (FG) porous sandwich (SW) plates. The material properties of FG sandwich porous plates (SWPPs) are defined by a modified mixing rule, supplemented by an additional term representing the porosity in the thickness of the FG layer. By incorporating indefinite integral variables, the number of unknowns and governing equations of the current theory is reduced, making it easier to use. Three common types of sandwich porous plates are considered in the analysis: an isotropic FG porous plate, an FG face plate with a homogeneous core, and a homogeneous face plate with an FG core. The current method considers both normal and shear deformations and satisfies the transverse shear stress-free boundary conditions at the top and bottom surfaces of the plate. The equilibrium equations are derived using the principle of virtual displacements. These equations are then solved using the Navier-type method. The influence of thickness strain and several parameters, including mechanical loads, porosity coefficients, layer thickness ratios, geometric parameters, and gradient indices, are studied. The numerical results of the present theory are similar to the predictions of quasi-3D theories with more unknowns, in addition to being more accurate than those obtained by higher-order shear deformation theories. The findings support the idea that the suggested theory offers an easy and effective method for predicting the buckling behavior of FG porous sandwich plates. The results show that, without taking into account transverse normal deformations, the plate is softer and the critical buckling load decreases. On the other hand, with transverse normal deformations, the plate is stiffer, which increases the critical buckling load.

Nonlinear buckling and postbuckling of heated functionally graded cylindrical shells under combined axial compression and radial pressure

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

This paper presents the vibro-acoustic modeling and analysis of sandwich plateswith metal–ceramic functionally graded (FG) core using a simplified first-order shear deformation theory and elemental radiator approach. A simply supported rectangular plate having functionally graded core, metal and ceramic facesheets is considered with aluminum as metal and alumina as ceramic. The material properties of the core are assumed to vary according to a power law distribution of the volume fraction of the constituents. The sound radiation due to point load and uniformly distributed load is computed by numerically solving the Rayleigh integral. The effective material properties of the sandwich plate are presented as a function of core thickness. The vibration parameters in terms of natural frequencies, plate displacement and velocity, and acoustic parameters such as radiated sound power level, radiated sound pressure level and radiation efficiency are computed for various values of the power law index. A comprehensive study of the influence of core thickness on vibro-acoustic performance is presented in terms of mean-squared velocity and overall sound power level. It is found that, for the plate being considered, the sound power level increases with increase in the power law index of the core at lower frequency segment. Increased vibro-acoustic response is observed in the high-frequency band for ceramic-rich FG core and in the low-frequency band for metal-rich FG core, respectively. A sandwich plate with metal-rich FG core configuration has shown improved flexural stiffness, compared to an FG plate with no significant rise in overall radiated sound. It is possible with this analysis to suitably tailor and optimize the sandwich FG plates for multifunctional performance and desired vibro-acoustic interaction.

Analytical non-linear analysis of functionally graded sandwich solid/annular sector plates

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 deformation of rotating functionally graded trapezoidal microplates in thermal environment