Plates In Thermal Environment Research Articles

Model updating of a plate structure in thermal environments using LR-SVR combined with particle swarm optimization

A novel model updating method based on Linear Regression and Support Vector Regression (LR-SVR) is proposed for a plate structure in thermal environments, in which the generalized eigenvalues of the mass and stiffness matrices are replaced by the natural frequencies. The proposed method demonstrates superior updating efficiency compared to traditional finite element model updating techniques and offers enhanced accuracy relative to conventional SVR-based model updating methods. The temperature-varying parameters are assumed to be polynomials w.r.t temperature. Virtual elements are introduced to facilitate boundary modeling, allowing for easier updating of the boundary conditions in the thermal environment. Both numerical simulation and experiment study on a two-side clamped plate in thermal environments are conducted to validate the efficacy of the proposed method. The experimental study accounts for a non-uniform temperature field, which can be predicted by the data obtained from both a thermal imager and thermocouples, employing a function interpolation scheme. The issue of initial deformation due to both inaccurate installation and thermal expansion is effectively resolved. The updated model exhibits high accuracy and efficiency in predicting the first five natural frequencies at different temperatures.

Nonlinear Vibration of Saturated Porous Functionally Graded Plate in Thermal Environment

In this work we studied investigates the nonlinear vibrations of a rectangular saturated porous functionally graded (FG) plate on elastic foundations in thermal environment. The mechanical properties of the saturated porous material vary smoothly with the thickness in three different distributions of porosity including uniform, symmetrically irregular, and asymmetrically irregular. The basic equations are employed by the Reddy’s higher order shear deformation theory, incorporating the geometrically nonlinear von Kármán strain-displacement relationship, stress-strain relations based on the elastic theory for porous materials by Biot, and an analytical solution obtained through the Galerkin method and Airy’s stress function for the simply supported plate. The influence of the geometrical and material parameters, elastic foundations and temperature increment on the nonlinear vibrations of the saturated porous FG plate were specifically evaluated through numerical investigations. 
 
 

Nonlinear resonance and chaotic dynamic of rotating graphene platelets reinforced metal foams plates in thermal environment

Nonlinear resonance and chaotic dynamic of rotating graphene platelets reinforced metal foams plates in thermal environment

Transient analysis of laminated plates in thermal environment

Transient displacement of laminated plates under combined load based on Mantari' s displacement field are investigated. The solution is implemented under transient mechanical load (sinusoidal, step and triangular sinusoidal distributed pressures pulse) and thermal buckling for plates with different layer orientation and thickness ratio. Equations of motion based on higher-order theory are derived through Hamilton' s principle, and solved using Naviertype solution for simply supported laminated plates. The results are presented for many effective parameters such as the number of laminate and orientation on the dynamic response of plates. Results show the validity of this displacement field in studying response of laminated thick and thin plates under varied transient loading and design parameters.

Nonlinear Free Vibration of Spinning Pre-Twisted Functionally Graded Material Plates in Thermal Environment

This paper investigates the nonlinear free vibration of spinning pre-twisted functionally graded material (FGM) plates in thermal environment. Based on the Kirchhoff plate theory and von Kármán large-deformation theory, the nonlinear dynamic model is established via the Lagrange equation, where the warping effect is taken into account. The material properties are related to temperature and change according to a power-law exponent distribution. The theoretical solution of nonlinear-free vibration is obtained using the multiple scale method. The effects of power-law exponent, temperature difference, spinning speed, hub radius ratio, and twist angle on nonlinear-free vibration characteristics of the spinning pre-twisted cantilever FGM plates are discussed. The results show that the spinning pre-twisted cantilever FGM plate exhibits nonlinear hardening-spring vibration behavior, while the characteristics weaken with the increase of spinning speed. The twist angle and setting angle have coupling effects on the nonlinear vibration characteristics of spinning pre-twisted FGM plates.

Buckling simulation of eccentrically rotating nanocomposite sector plates in thermal environment using the 2D Chebyshev collocation method

The present paper investigates the inertial stability of a graphene platelet (GPL) reinforced nanocomposite sector plate eccentrically rotating with a constant angular velocity. The axis of spinning is perpendicular to the plate and parallel to the transverse direction of origin. It is considered at a distance and angle to the plate coordinate origin. A uniform thermal environment is considered that affects the plate response. The nanocomposite is regarded as a laminated plate in which the GPLs in each layer are orientated and dispersed equally and randomly. The volume fraction of particles varies from layer to layer based on functionally graded (FG) linear models suitable for studying the buckling phenomenon. The pre-buckling and stability paths are separated by utilizing the adjacent equilibrium criterion. Both paths are solved by implementing the Chebyshev Collocation (CC) technique. The consequences of geometrical parameters, nanocomposite characteristics, and eccentric angle and distance on the stability of the current system are investigated. It will be revealed that the eccentric distance, according to its angle, can significantly increase or decrease the critical speed of the fabrication.

Stochastic dynamic analysis of composite plates in thermal environments using nonlinear autoregressive model with exogenous input in polynomial chaos expansion surrogate

The application of composite materials has increased manifolds in aerospace and high-speed vehicle industries, where structures experience dynamic loads along with temperature variation. To ensure safety of these structures, the stochastic dynamic analysis in varying thermal environments is essential. The generalized polynomial chaos (gPC) expansion method is a well-known metamodel used to quantify uncertainties in engineering systems instead of using the direct Monte Carlo simulation. Though the gPC expansion method is used extensively for engineering systems, its classical version has some limitations while implementing in dynamical systems. The accuracy of the gPC expansion method reduces in delayed time domain and can be improved to some extent by increasing the order of polynomial, which though is computationally intensive. Furthermore, the classical gPC expansion method is suitable for low-dimensional problems having independent random parameters. To overcome these limitations in the classical gPC expansion method, a system identifier, i.e., nonlinear autoregressive model with exogenous input (NARX) is coupled with it to avoid response degeneration in delayed time domain. The temperature-dependent material properties of composite lamina can be random and correlated, however the classical gPC expansion method is unable to accommodate the correlated random parameters. To address these challenges, the NARX-gPC expansion method is modified to conduct stochastic dynamic analysis of composite plates using correlated random material properties of the composite lamina in varying thermal environments. The study indicates that the correlation has a significant effect on the stochastic dynamic response at low and high temperatures for cross-ply laminates in comparison with angle-ply laminates, which is not captured through uncorrelated random material properties. The prediction efficiency of the developed surrogate by using the adaptive NARX-gPC expansion method is established even though it is trained using data in a shorter time domain, thereby computational performance is enhanced. Additionally, this surrogate is implemented effectively for higher order randomness in the input parameters.

Buckling analysis of functionally graded plates in thermal environment by using a meshfree method

In material, the pre-stress state caused by temperature variation of the working environment is one of the main reasons which cause buckling in structures. This paper aims to analyse the critical temperature rise to cause buckling in functionally graded material (FGM) under different boundary conditions. Reissner-Mindlin plate theory is employed in this paper with the radial point interpolation method (RPIM). The RPIM has the advantage compared to other meshfree methods in the satisfaction of the Kronecker delta property which allows directly imposing boundary conditions on scattered nodes. Factors affecting to thermal buckling phenomenon are investigated. The accuracy of solutions will be shown by comparing them to reliable results in previous studies

NES-Based Multi-mode Vibration Absorber for a Sandwich Plate in Thermal Environment

NES-Based Multi-mode Vibration Absorber for a Sandwich Plate in Thermal Environment

Optimization of multi-directional functionally graded plates in thermal environment based on 3D isogeometric analysis and adaptive-hybrid evolutionary firefly algorithm

In this study, a numerical model based on three-dimensional isogeometric analysis and adaptive hybrid evolutionary firefly algorithm is developed to concurrently optimize the shape and material distribution of multi-directional functionally graded plates. The optimization problems focus on maximizing the fundamental frequency of the plates subjected to thermal effects, while the volume fraction of ceramic constituent material and volume of the plates are considered as side constraints. Isogeometric multi-mesh design approach is employed to generate design and analysis domain. The free vibration analysis of multi-directional functionally graded plates with variable thickness is conducted within the framework of three-dimensional elasticity theory and isogeometric analysis. The generalized numerical framework developed in this study could accurately capture the thermal effects on the behavior of nonhomogeneous plates with variable thickness. Various numerical examples are conducted to illustrate the optimal shapes and material distributions within square, rectangular, and circular plates. Influences of temperature field, boundary conditions, and geometries of the plates on the optimal results are also addressed.

A Moving Kriging Interpolation Meshless for Bending and Free Vibration Analysis of the Stiffened FGM Plates in Thermal Environment

This paper adopts the Moving Kriging (MK) interpolation meshless method to analyze the static and dynamic behaviors of stiffened functionally graded material (FGM) plate in thermal environment based on the physical neutral surface. The ribbed FGM plate is regarded as a composite structure of a FGM plate and ribs. The displacement transformation relationship between stiffeners and FGM plates is obtained through the displacement compatible conditions and MK interpolation. The meshfree model for ribbed FGM plate is obtained by superimposing the total energy of the FGM plate and the stiffeners based on the first-order shear deformation theory (FSDT) and physical neutral surface. The nonlinear temperature field along thickness direction is introduced into the meshless model of stiffened FGM plate. The equations governing the bending and free vibration of the ribbed FGM plate in thermal environment are obtained according to the principle of Minimum Potential Energy and Hamilton’s Principle. Thereafter, several ribbed FGM plate examples in different temperatures and with different locations of ribs are calculated. The results are compared with those given by the ABAQUS and literature. The results show that the effectiveness and accuracy of the proposed method in analyzing the ribbed FGM plate in thermal environment.

Bending Analysis of Asymmetric Functionally Graded Material Sandwich Plates in Thermal Environments

This paper investigates the bending of asymmetric functionally graded material (FGM) sandwich plates subjected to thermo-mechanical loads in thermal environments. In this paper, a thermo-mechanical analysis model for asymmetric FGM sandwich plates is proposed, which contains only four control equations and four unknown variables. The governing equation is obtained through refined shear theory and the principle of virtual work, and the Navier method is used to solve it. Numerical examples of simply supported FGM sandwich plates under thermo-mechanical loads are given to verify the accuracy of the model. Finally, detailed studies are conducted on the bending of asymmetric FGM sandwich plates under thermo-mechanical loads, exploring the effects of various parameter changes on their bending behavior, and providing strong guidance for the application of asymmetric FGM sandwich plates in industrial production practice.

Nonlinear static analysis of bi-directional functionally graded sandwich plates in thermal environments by a higher-order finite element model

This study addresses nonlinear static behaviours of bi-directional functionally graded (2D-FGM) sandwich plates lying on an elastic foundation in thermal environments for the first time. The plates comprise two 2D-FGM face sheets and a homogeneous core layer. The material properties of the face sheets change according to the power law in both the longitudinal and thickness directions. Furthermore, the material properties also possess temperature-dependent characteristics in the thermal environment. For the analysis purpose, a higher-order finite element model (FEM) based on Shi’s plate theory that takes into account the geometrically nonlinear von Kármán without regard to material nonlinearity is established. The minimum potential energy principle is used to establish the weak form of governing equations. The four-node rectangular element with the Lagrange and Hermitian interpolation functions is used to discretize the domain of the plate. The nonlinear equilibrium equations are solved by employing Newton–Raphson iterative procedure. The numerical examples comparing the obtained results with the published results in open literature have confirmed the accuracy and convergence of the proposed model. Finally, a few novel parametric studies are conducted to show the effects of the material properties, geometric parameters, temperature, elastic foundation stiffness, and boundary conditions on the nonlinear static behaviours of the 2D-FGM sandwich plates.

Influences of arbitrary-distributed Kerr foundation on free vibration and nonlinear transient response of functionally graded plate in thermal environment

For the first time, a novel theoretical model is presented for analyzing the effects of the arbitrary-distributed Kerr foundation on the free vibration and transient responses of the functionally graded material (FGM) plate in a thermal environment. According to the power law distribution, the mechanical characteristics of FGM plates are assumed to vary with plate thickness. The three-parameter Kerr model is founded on the independence of the upper and lower elastic layers with respect to the shear layer. The shape and location of the elastic foundation can be determined arbitrarily using mathematical functions. In the area of the FGM plate, the distribution of the elastic foundation is assumed to be either centralized or decentralized. The Reddy’s third-order shear deformation theory is utilized to express the governing equations. Then, the dynamical characteristics of the FGM plate are obtained by using the Galerkin’s method. To validate the accuracy of the current computational model, the achieved results are compared to those derived from published literature. In addition, graphical representations of the effects of stiffness, distributions, and geometrical parameters of elastic foundation, geometrical parameters of plate, material properties, and thermal environment on the vibrational characteristics of the plates are provided.

Dynamic Analysis of Laminated Composite Wave Plate in Thermal Environment Using Meshfree Method

Dynamic Analysis of Laminated Composite Wave Plate in Thermal Environment Using Meshfree Method

Vibration analysis of the combined conical–cylindrical​ shells coupled with annular plates in thermal environment

In this paper, a unified method is proposed for the first time to predict the free and forced vibration behavior of the combined conical–cylindrical shells coupled with annular plates in the steady-state thermal environment. The energy equations of each substructure are obtained based on the first-order shear deformation theory (FSDT), and the artificial spring technique is introduced to realize the coupling between each substructure, the circumferential closure of each substructure, and the arbitrary boundary conditions. The displacements of the midface in each sub-structure are expanded using the spectral-geometry method (SGM), and the energy expression is solved by using the Rayleigh–Ritz method to obtain the free and forced vibration behavior of the combined structure. The numerical examples derived from the calculations are compared with the results obtained by the finite element method (FEM) to verify the accuracy of the present method. The effects of boundary conditions, temperature and geometric parameters on the free and forced vibration behaviors of the combined structure are investigated. The method in this paper is a meshless method, which is faster and more efficient as it is less dimensional and less computationally expensive than the FEM. This paper provides a compelling reference for vibration control of the combined conical–cylindrical shells coupled with annular plates in practical applications.

Free vibration of functionally graded sandwich plates in thermal environments

AbstractThis paper presents an analytical solution for the free vibration of functionally graded material (FGM) sandwich plates in a thermal environment. An equivalent‐single‐layer (ESL) plate theory with four variables is used to obtain the solution. Two types of sandwich plates are examined in this study: one with FGM face sheets and a homogeneous core and the other with an FGM core and homogeneous face sheets. The governing equations of motion are derived based on Hamilton's principle and then solved using the Navier method. The results of natural frequencies of simply supported FGM sandwich plates are compared with the available solutions in the literature. The effects of volume fraction distribution, geometrical parameters, and temperature increments on the free vibration characteristics are discussed in detail.

Equivalent dynamic modeling of functionally graded porous sandwich plates in thermal environment

Functionally graded porous (FGP) sandwich structures offer unique potential in aircraft, aerospace, flexible electronics, biomedical areas and so on. Understanding the mechanical behaviors of these structures is essential for their successful applications. In this work, free vibration of FGP sandwich plates in thermal environment is theoretically investigated. The gradation is achieved by changing the porosity through the plate thickness, rather than using functionally graded materials (FGMs). Several types of FGP sandwich plates are taken into account. An equivalent single layer (ESL) theory is developed to investigate the natural frequencies and mode shapes of simply supported FGP sandwich plates. The present theory is validated by comparing calculated results with those from the existing literature. Parametric studies are conducted to demonstrate the influences of different porosity distributions, geometric parameters and temperature on the vibration behavior of FGP sandwich plates. This work can provide theoretical reference for design and optimization of FGP sandwich structures.

Stability of functionally graded graphene-reinforced composite laminated thick plates in thermal environment

Stability of functionally graded graphene-reinforced composite laminated thick plates in thermal environment

Vibration and acoustic radiation characteristics of simply supported curved plate in thermal environment

Vibration and acoustic radiation characteristics of simply supported curved plate in thermal environment