Nonlinear Post-Buckling of CNTs Reinforced Sandwich-Structured Composite Annular Spherical Shells

2019 ◽  
Vol 20 (02) ◽  
pp. 2050018 ◽  
Author(s):  
Dương Tuan Manh ◽  
Vu Thi Thuy Anh ◽  
Pham Dinh Nguyen ◽  
Nguyen Dinh Duc
Keyword(s):  
Stress Function ◽  
Mechanical Response ◽  
Thermal Environment ◽  
Geometrical Nonlinearity ◽  
Sheet Thickness ◽  
Sandwich Composite ◽  
Geometrical Parameters ◽  
Elastic Foundations ◽  
Nonlinear Mechanical ◽  
Post Buckling

This work presents the nonlinear post-buckling behavior of carbon nanotubes (CNTs) reinforced sandwich composite annular spherical (AS) shells supported by elastic foundations in the thermal environment. This paper takes advantage of the sandwich-structured configuration with three layers: two nanocomposite face sheets and an isotropic core to analyze the static problem. Due to the precious properties, CNTs are applied to reinforce nanocomposite face sheets of AS shells. The governing equations of the nonlinear mechanical response of CNTs reinforced sandwich-structured composite (SSC) AS shells are achieved by using the classical shell theory (CST) and taking von Kármán’s geometrical nonlinearity into account. Applying Airy’s stress function and an approximate solution, we propose a form of stress function for CNTs reinforced SSC AS shells. The detailed effects of different types of CNTs’ reinforcement and volume fractions, geometrical parameters, core to face sheet thickness ratio, Winkler and Pasternak elastic foundations on the nonlinear mechanical post-buckling analysis are examined.

An analytical approach on nonlinear mechanical and thermal post-buckling of nanocomposite double-curved shallow shells reinforced by carbon nanotubes

2018 ◽  
Vol 233 (11) ◽  
pp. 3888-3903 ◽  
Author(s):  
Nguyen Dinh Duc ◽  
Pham Dinh Nguyen ◽  
Nguyen Huy Cuong ◽  
Nguyen Van Sy ◽  
Nguyen Dinh Khoa
Keyword(s):  
Carbon Nanotubes ◽  
Amorphous Polymer ◽  
Geometrical Nonlinearity ◽  
Shear Deformation Theory ◽  
Functionally Graded ◽  
Shallow Shells ◽  
Elastic Foundations ◽  
Nonlinear Mechanical ◽  
Post Buckling ◽  
The Galerkin Method

This work presents the nonlinear mechanical and thermal post-buckling of nanocomposite double-curved shallow shells reinforced by single-walled carbon nanotubes resting on elastic foundations based on the higher order shear deformation theory with geometrical nonlinearity in von Karman–Donnell sense. The composite shells are made of various amorphous polymer matrices: poly(methyl methacrylate) (PMMA) and poly{(m-phenylenevinylene)-co-[(2,5-dioctoxy-p-phenylene) vinylene]} (PmPV). The governing equations are solved by the Galerkin method and Airy's stress function to achieve mechanical and thermal post-buckling behaviors of nanocomposite double-curved shallow shells. Various types of distributions of carbon nanotubes, both uniform distributions, and functionally graded distributions are examined. The material properties of nanocomposite double-curved shallow shells are assumed to be temperature dependent. Detailed parametric studies are carried out on the effect of various types of distribution and volume fractions of carbon nanotubes, temperature increments, elastic foundations, edge to radius and edge to thickness ratios on the nonlinear mechanical and thermal post-buckling of nanocomposite double-curved shallow shells reinforced by CNTs.

Nonlinear dynamic response and vibration of imperfect eccentrically stiffened sandwich third-order shear deformable FGM cylindrical panels in thermal environments

2017 ◽  
Vol 21 (8) ◽  
pp. 2816-2845 ◽  
Author(s):  
Nguyen D Duc ◽  
Ngo Duc Tuan ◽  
Phuong Tran ◽  
Tran Q Quan ◽  
Nguyen Van Thanh
Keyword(s):  
Dynamic Response ◽  
Nonlinear Dynamic ◽  
Geometrical Nonlinearity ◽  
Cylindrical Panel ◽  
Geometrical Parameters ◽  
Third Order ◽  
Nonlinear Dynamic Response ◽  
Elastic Foundations ◽  
Thermal Environments ◽  
Cylindrical Panels

This study follows an analytical approach to investigate the nonlinear dynamic response and vibration of eccentrically stiffened sandwich functionally graded material (FGM) cylindrical panels with metal–ceramic layers on elastic foundations in thermal environments. It is assumed that the FGM cylindrical panel is reinforced by the eccentrically longitudinal and transversal stiffeners and subjected to mechanical and thermal loads. The material properties are assumed to be temperature dependent and graded in the thickness direction according to a simple power law distribution. Based on the Reddy’s third-order shear deformation shell theory, the motion and compatibility equations are derived taking into account geometrical nonlinearity and Pasternak-type elastic foundations. The outstanding feature of this study is that both FGM cylindrical panel and stiffeners are assumed to be deformed in the presence of temperature. Explicit relation of deflection–time curves and frequencies of FGM cylindrical panel are determined by applying stress function, Galerkin method and fourth-order Runge-Kutta method. The influences of material and geometrical parameters, elastic foundations and stiffeners on the nonlinear dynamic and vibration of the sandwich FGM panels are discussed in detail. The obtained results are validated by comparing with other results in the literature.

scholarly journals Nonlinear thermo-mechanical stability of shear deformable FGM sandwich shallow spherical shells with tangential edge constraints

2017 ◽  
Vol 39 (4) ◽  
pp. 351-364
Author(s):  
Nguyen Minh Khoa ◽  
Hoang Van Tung
Keyword(s):  
Mechanical Stability ◽  
Effective Properties ◽  
Geometrical Nonlinearity ◽  
Geometrical Parameters ◽  
Boundary Edge ◽  
Power Law Distribution ◽  
Spherical Shells ◽  
Nonlinear Load ◽  
Elastic Foundations ◽  
Thermal Environments

This paper presents an analytical approach to investigate the nonlinear axisymmetric response of moderately thick FGM sandwich shallow spherical shells resting on elastic foundations, exposed to thermal environments and subjected to uniform external pressure. Material properties are assumed to be temperature independent, and effective properties of FGM layer are graded in the thickness direction according to a simple power law distribution in terms of the volume fractions of the constituents. Formulations are based on first-order shear deformation shell theory taking geometrical nonlinearity, initial geometrical imperfection, Pasternak type elastic foundations and various degree of tangential constraint of boundary edge into consideration. Approximate solutions are assumed to satisfy clamped boundary condition and Galerkin method is applied to derive closed-form expressions of critical buckling loads and nonlinear load-deflection relation. Effects of geometrical parameters, thickness of face sheets, foundation stiffness, imperfection, thermal environments and degree of tangential edge constraints on the nonlinear stability of FGM sandwich shallow spherical shells are analyzed and discussed. 

Nonlinear Thermo-Mechanical Stability Analysis of Eccentrically Spiral Stiffened Sandwich Functionally Graded Cylindrical Shells Subjected to External Pressure

2019 ◽  
Vol 11 (05) ◽  
pp. 1950045 ◽  
Author(s):  
Vu Hoai Nam ◽  
Nguyen Thi Phuong ◽  
Cao Van Doan ◽  
Nguyen Thoi Trung
Keyword(s):  
Mechanical Stability ◽  
Thermal Environment ◽  
Cylindrical Shells ◽  
Geometrical Nonlinearity ◽  
External Pressure ◽  
Functionally Graded ◽  
Geometrical Parameters ◽  
Nonlinear Buckling ◽  
Circular Cylindrical Shells ◽  
The Galerkin Method

A new analytical approach to investigate the nonlinear buckling and postbuckling of the sandwich functionally graded circular cylindrical shells reinforced by ring and stringer or spiral stiffeners subjected to external pressure is presented in this paper. By employing the Donnell shell theory, the geometrical nonlinearity in Von Kármán sense and developed Lekhnitskii’s smeared stiffener technique, the governing equations of sandwich functionally graded circular cylindrical shells are derived. Resulting equations are solved by applying the Galerkin method to obtain the explicit expression of critical buckling external pressure load and postbuckling load–deflection curve. Effects of spiral stiffeners, thermal environment, external pressure, and geometrical parameters on nonlinear buckling behavior of sandwich functionally graded circular cylindrical shells are shown in numerical results.

Nonlinear thermo-mechanical dynamic analysis and vibration of higher order shear deformable piezoelectric functionally graded material sandwich plates resting on elastic foundations

2016 ◽  
Vol 20 (2) ◽  
pp. 191-218 ◽  
Author(s):  
Nguyen Dinh Duc ◽  
Pham Hong Cong
Keyword(s):  
Dynamic Analysis ◽  
Material Properties ◽  
Nonlinear Dynamic ◽  
Thermal Environment ◽  
Nonlinear Dynamic Analysis ◽  
Higher Order ◽  
Functionally Graded ◽  
Geometrical Parameters ◽  
Sandwich Plates ◽  
Elastic Foundations

Used the Reddy's higher-order shear deformation plate theory, the nonlinear dynamic analysis and vibration of imperfect functionally graded sandwich plates in thermal environment with piezoelectric actuators (PFGM) on elastic foundations subjected to a combination of electrical, damping loadings and temperature are investigated in this article. One of the salient features of this work is the consideration of temperature on the piezoelectric layer, and the material properties of the PFGM sandwich plates are assumed to be temperature-dependent. The governing equations are established based on the stress function, the Galerkin method, and the Runge–Kutta method. In the numerical results, the effects of geometrical parameters; material properties; imperfections; elastic foundations; electrical, thermal, and damping loads on the vibration and nonlinear dynamic response of the PFGM sandwich plates are discussed. The obtained natural frequencies are verified with the known results in the literature.

Nonlinear analysis of stability for imperfect eccentrically stiffened FGM plates under mechanical and thermal loads based on FSDT. Part 2: Numerical results and discussions

2015 ◽  
Vol 37 (4) ◽  
pp. 251-262
Author(s):  
Dao Van Dung ◽  
Nguyen Thi Nga
Keyword(s):  
Shear Deformation ◽  
Volume Fraction ◽  
Plate Theory ◽  
Buckling Load ◽  
Geometrical Parameters ◽  
Thermal Loads ◽  
First Order ◽  
Elastic Foundations ◽  
Buckling Behavior ◽  
Post Buckling

Based on the first-order shear deformation plate theory (FSDT), the smeared stiffeners technique and Galerkin method, the analytical expressions to determine the static critical buckling load and analyze the post-buckling load-deflection curves of FGM plates reinforced by FGM stiffeners resting on elastic foundations and subjected to in-plane compressive loads or thermal loads are established in part 1. In this part, we will use them to study the effects of temperature, stiffener, volume fraction index, geometrical parameters, elastic foundations on the buckling and post-buckling behavior of plates. In addition, the results in comparisons between the classical plate theory (CPT) and the first order shear deformation theory (FSDT) also are carried out and shown that the buckling and post-buckling behavior of more thick plate should be studied by FSDT.

Nonlinear Vibration of Carbon Nanotube Reinforced Composite Truncated Conical Shells in Thermal Environment

2019 ◽  
Vol 19 (12) ◽  
pp. 1950158 ◽  
Author(s):  
Pham Dinh Nguyen ◽  
Vu Dinh Quang ◽  
Vu Thi Thuy Anh ◽  
Nguyen Dinh Duc
Keyword(s):  
Carbon Nanotube ◽  
Dynamic Response ◽  
Nonlinear Vibration ◽  
Thermal Environment ◽  
Equations Of Motion ◽  
Linear Functions ◽  
Geometrical Parameters ◽  
Conical Shells ◽  
Elastic Foundations ◽  
Reinforced Composite

This paper is concerned with the nonlinear vibration and dynamic response of carbon nanotube (CNT) reinforced composite truncated conical shells resting on elastic foundations in a thermal environment. The material properties of shells are assumed to be temperature-dependent and graded in the thickness direction according to various linear functions. The nonlinear equations of motion are expressed in the form of two-component deflection function and solved by the analytical method. Detailed studies for the influences of various types of distribution and volume fractions of CNTs, geometrical parameters, Winkler and Pasternak elastic foundations on the dynamic response and nonlinear vibration of CNT polymer composite truncated conical shells are examined and the comparison study is carried out to verify the accuracy and efficiency of the proposed method.

A data mining approach to the diagnosis of failure modes for two serial fastened sandwich composite plates

2016 ◽  
Vol 51 (20) ◽  
pp. 2853-2862 ◽  
Author(s):  
Serkan Ballı
Keyword(s):  
Data Mining ◽  
Random Forest ◽  
Failure Modes ◽  
Composite Plates ◽  
Study Data ◽  
Sandwich Composite ◽  
Support Vector ◽  
Geometrical Parameters ◽  
Mining Methods

The aim of this study is to diagnose and classify the failure modes for two serial fastened sandwich composite plates using data mining techniques. The composite material used in the study was manufactured using glass fiber reinforced layer and aluminum sheets. Obtained results of previous experimental study for sandwich composite plates, which were mechanically fastened with two serial pins or bolts were used for classification of failure modes. Furthermore, experimental data from previous study consists of different geometrical parameters for various applied preload moments as 0 (pinned), 2, 3, 4, and 5 Nm (bolted). In this study, data mining methods were applied by using these geometrical parameters and pinned/bolted joint configurations. Therefore, three geometrical parameters and 100 test data were used for classification by utilizing support vector machine, Naive Bayes, K-Nearest Neighbors, Logistic Regression, and Random Forest methods. According to experiments, Random Forest method achieved better results than others and it was appropriate for diagnosing and classification of the failure modes. Performances of all data mining methods used were discussed in terms of accuracy and error ratios.

Dynamical Behaviors of Sinusoidal Nanocomposite Plates Subjected to Thermomechanical Loads

2021 ◽  
Author(s):  
Vu Ngoc Viet Hoang ◽  
Dinh Gia Ninh
Keyword(s):  
Thermal Environment ◽  
Plate Theory ◽  
Micromechanical Model ◽  
Functionally Graded ◽  
Geometrical Parameters ◽  
Rectangular Plates ◽  
Sine Function ◽  
Classical Plate Theory ◽  
Wolfram Mathematica ◽  
Number Of Cycles

In this paper, a new plate structure has been found with the change of profile according to the sine function which we temporarily call as the sinusoidal plate. The classical plate theory and Galerkin’s technique have been utilized in estimating the nonlinear vibration behavior of the new non-rectangular plates reinforced by functionally graded (FG) graphene nanoplatelets (GNPs) resting on the Kerr foundation. The FG-GNP plates were assumed to have two horizontal variable edges according to the sine function. Four different configurations of the FG-GNP plates based on the number of cycles of sine function were analyzed. The material characteristics of the GNPs were evaluated in terms of two models called the Halpin–Tsai micromechanical model and the rule of mixtures. First, to verify this method, the natural frequencies of new non-rectangular plates made of metal were compared with those obtained by the Finite Element Method (FEM). Then, the numerical outcomes are validated by comparing with the previous papers for rectangular FGM/GNP plates — a special case of this structure. Furthermore, the impacts of the thermal environment, geometrical parameters, and the elastic foundation on the dynamical responses are scrutinized by the 2D/3D graphical results and coded in Wolfram-Mathematica. The results of this work proved that the introduced approach has the advantages of being fast, having high accuracy, and involving uncomplicated calculation.

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