Static and Dynamic Analyses of Nanocomposite Plates in Mechanical and Aerodynamic Loading

2020 ◽  
Vol 12 (03) ◽  
pp. 2050034 ◽  
Author(s):  
Kazem Majidi-Mozafari ◽  
Reza Bahaadini ◽  
Ramin Bahaadini ◽  
Faramarz Abbasi ◽  
Hanif Maghzi
Keyword(s):  
Eigenvalue Problem ◽  
Porous Plate ◽  
Weight Fraction ◽  
Graphene Nanoplatelets ◽  
Functionally Graded ◽  
Complex Eigenvalue ◽  
Aerodynamic Pressure ◽  
The Matrix ◽  
Porosity Coefficient ◽  
Plate Strip

In this paper, flutter and divergence instabilities of functionally graded porous plate strip reinforced with graphene nanoplatelets in supersonic flow and subjected to an axial loading are studied. The graphene nanoplatelets are distributed in the matrix either uniformly or non-uniformly along the thickness direction. Four graphene nanoplatelets distribution patterns namely, Patterns A through D are considered. Based on the modified Halpin–Tsai micromechanics model and the rule of mixture, the effective material properties of functionally graded plate strip reinforced with graphene nanoplatelets are obtained. The aerodynamic pressure is considered in accordance with the quasi-steady supersonic piston theory. To transform the governing equations of motion to a general eigenvalue problem, the Galerkin method is employed. The flutter aerodynamic pressure and stability boundaries are determined by solving standard complex eigenvalue problem. The effects of graphene nanoplatelets distributions, graphene nanoplatelets weight fraction, geometry of graphene nanoplatelets, porosity coefficient and porosity distributions on the flutter and divergence instabilities of the system are studied. The results show that the plate strip with symmetric distribution pattern (stiffness in the surface areas) and GPLs pattern A predict the highest stable area. The flutter and divergence regions decrease as the porosity coefficient increases. Besides, the critical aerodynamic loads increase by adding a small amount of GPL to the matrix.

scholarly journals Vibration and Buckling Characteristics of Functionally Graded Graphene Nanoplatelets Reinforced Composite Beams with Open Edge Cracks

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1412 ◽  
Author(s):  
Meifung Tam ◽  
Zhicheng Yang ◽  
Shaoyu Zhao ◽  
Jie Yang
Keyword(s):  
Fundamental Frequency ◽  
Slenderness Ratio ◽  
Weight Fraction ◽  
Graphene Nanoplatelets ◽  
Functionally Graded ◽  
Buckling Load ◽  
Critical Buckling Load ◽  
Reinforced Composite ◽  
Edge Cracks ◽  
Open Edge

This paper investigates the free vibration and compressive buckling characteristics of functionally graded graphene nanoplatelets reinforced composite (FG-GPLRC) beams containing open edge cracks by using the finite element method. The beam is a multilayer structure where the weight fraction of graphene nanoplatelets (GPLs) remains constant in each layer but varies along the thickness direction. The effective Young’s modulus of each GPLRC layer is determined by the modified Halpin-Tsai micromechanics model while its Poisson’s ratio and mass density are predicted according to the rule of mixture. The effects of GPLs distribution pattern, weight fraction, geometry, crack depth ratio (CDR), slenderness ratio as well as boundary conditions on the fundamental frequency and critical buckling load of the FG-GPLRC beam are studied in detail. It was found that distributing more GPLs on the top and bottom surfaces of the cracked FG-GPLRC beam provides the best reinforcing effect for improved vibrational and buckling performance. The fundamental frequency and critical buckling load are also considerably affected by the geometry and dimension of GPL nanofillers.

Aeroelastic Flutter Analysis of Thick Porous Plates in Supersonic Flow

2019 ◽  
Vol 11 (10) ◽  
pp. 1950096 ◽  
Author(s):  
Reza Bahaadini ◽  
Ali Reza Saidi ◽  
Kazem Majidi-Mozafari
Keyword(s):  
Supersonic Flow ◽  
Plate Theory ◽  
Equations Of Motion ◽  
Functionally Graded ◽  
Governing Equations ◽  
Aerodynamic Pressure ◽  
Aeroelastic Flutter ◽  
Piezoelectric Layers ◽  
Flutter Analysis ◽  
Porosity Coefficient

The aeroelastic flutter analysis of thick porous plates surrounded with piezoelectric layers in supersonic flow is studied. In order to aeroelastic analysis of the thick porous-cellular plate, Reddy’s third-order shear deformation plate theory and first-order piston theory are used. Furthermore, the plate is composed of two face piezoelectric layers and three functionally graded porous distributions core. Applying the extended Hamilton’s principle and Maxwell’s equation, the governing equations of motion are obtained. The partial differential governing equations are transformed into a set of ordinary differential equations by applying Galerkin’s approach. The effects of porosity coefficient, porosity distributions, piezoelectric layers, geometric dimensions, electrical and mechanical boundary conditions on the flutter aerodynamic pressure and natural frequencies of porous-cellular plates are investigated.

Buckling and Postbuckling of Plates Made of FG-GPL-Reinforced Porous Nanocomposite with Various Shapes and Boundary Conditions

2021 ◽  
pp. 2150063
Author(s):  
R. Ansari ◽  
R. Hassani ◽  
R. Gholami ◽  
H. Rouhi
Keyword(s):  
Boundary Conditions ◽  
Micromechanical Model ◽  
Gaussian Random Field ◽  
Shear Deformation Theory ◽  
Composite Plates ◽  
Weight Fraction ◽  
Numerical Approach ◽  
Functionally Graded ◽  
Dispersion Pattern ◽  
Porosity Coefficient

Within the framework of a variational mixed formation and higher-order shear deformation theory (HSDT), a numerical approach is developed in this research to investigate the buckling and post buckling behaviors of variously-shaped plates made of functionally graded graphene platelet-reinforced composites (FG-GPLRCs) taking the effect of porosity into account. By the proposed approach, which can be named as VDQ-FEM, thick and moderately thick plate-type structures with different shapes (e.g. rectangular, skew, or quadrilateral) with arbitrary-shaped cutout (e.g. circular or rectangular) can be studied. Various types for porosity distribution scheme and GPL dispersion pattern including uniform and different functionally graded patterns are considered along the thickness of plate. In the computation of material properties, the closed-cell Gaussian Random field scheme and Halpin–Tsai micromechanical model are utilized. One of the key novelties of proposed approach is developing an efficient way according to the mixed formulation to accommodate the continuity of first-order derivatives on the common boundaries of elements for the used HSDT model. Several numerical examples are given to analyze the influences of porosity coefficient/distribution pattern, GPL weight fraction/dispersion pattern, cutout and boundary conditions on the buckling and postbuckling characteristics of FG-GPLR porous composite plates.

Modeling and free vibration analysis of rotating hub-blade assemblies reinforced with graphene nanoplatelets

2021 ◽  
pp. 030932472098690
Author(s):  
Tian Yu Zhao ◽  
Ze Yu Jiang ◽  
Zhan Zhao ◽  
Li Yang Xie ◽  
Hui Qun Yuan
Keyword(s):  
Free Vibration ◽  
Synthesis Method ◽  
Free Vibration Analysis ◽  
Material Design ◽  
Weight Fraction ◽  
Mathematic Model ◽  
Graphene Nanoplatelets ◽  
Functionally Graded ◽  
Width Ratio ◽  
Graphene Nanoplatelet

This paper presents a new theoretical model for rotating elastic hub-blade assemblies, made of functionally graded (FG) graphene nanoplatelet (GPL) reinforced nanocomposites, and their free vibration characteristics are investigated. This model is the first attempt to include two elastic components simultaneously and consider the coupled effect. The Euler-Bernoulli beam theory and the Donnell’s shell theory are employed to establish the mathematic model of the blade and hub, respectively. The effective material properties, varying continuously along the thickness of the beam and cylindrical shell, are determined via the Halpin-Tsai micromechanics model and the rule of the mixture. The Lagrange’s equation is adopted to derive the equations of motion which are then solved by employing the substructure mode synthesis method and the Galerkin method. A parametric study is conducted to examine the effects of the rotating speed, graphene nanoplatelet distribution pattern, GPL weight fraction, length-to-thickness ratio and length-to-width ratio of graphene nanoplatelets (GPLs) and blade dimension on the natural frequencies of the nanocomposite rotor system, which will significantly benefit on the structural and material design of GPL reinforced hub-blade assembly.

scholarly journals Vibration characteristics of rotating functionally graded porous beams reinforced by graphene platelets

2021 ◽  
Vol 15 (4) ◽  
pp. 29-41
Author(s):  
Chu Thanh Binh ◽  
Tran Huu Quoc ◽  
Duong Thanh Huan ◽  
Ho Thi Hien
Keyword(s):  
Dispersion Model ◽  
Equations Of Motion ◽  
Ritz Method ◽  
Beam Theory ◽  
Weight Fraction ◽  
Vibration Characteristics ◽  
Functionally Graded ◽  
Rotating Speed ◽  
Porosity Coefficient ◽  
Graphene Platelets

This work aims to study the vibration characteristics of the rotating functionally graded porous beam reinforced by graphene platelets. The beam is mounted and rotated around a hub with a constant velocity. The material properties vary along the thickness direction with two types of porosity distributions and two dispersion patterns of graphene platelet. The equations of motion based on the Timoshenko beam theory are obtained and solved using the Chebyshev-Ritz method. The effects of the parameters such as hub radius, rotating speed, weight fraction, porosity distribution, porosity coefficient, and dispersion model are presented. The present method results are also compared with numerical results available in the literature.

Thermal Buckling of Graphene Platelets Toughening Sandwich Functionally Graded Porous Plate with Temperature-Dependent Properties

2020 ◽  
Vol 12 (08) ◽  
pp. 2050089
Author(s):  
Mingnan Xu ◽  
Xinping Li ◽  
Yi Luo ◽  
Gang Wang ◽  
Yunhua Guo ◽  
...  
Keyword(s):  
Plate Theory ◽  
Porous Plate ◽  
Weight Fraction ◽  
Analytical Framework ◽  
Thermal Buckling ◽  
Functionally Graded ◽  
Temperature Dependent ◽  
Graphene Platelets ◽  
Temperature Dependent Properties ◽  
Parametric Analyses

Thermal buckling of graphene platelets (GPLs) reinforced sandwich functionally graded porous (SWFGP) plate with temperature-dependent (TD) properties is investigated. The studied plate is composed of two homogeneous face layers and one functionally graded porous core. Two types of porosity distribution with uniformly distributed GPL reinforcement are included. Based on the first-order shear deformation plate theory, Hamilton principle and Galerkin procedure are employed to build the analytical framework. Uniform, linear, and nonlinear thermal loads along the thickness direction are considered. Subsequently, an iterative procedure is introduced to find out the critical buckling temperature of the plate with the temperature dependence considered. Verifications are conducted to demonstrate the accuracy of the proposed method. Several parametric analyses are investigated in detail where the effects of porosity, GPL weight fraction, geometric configuration, and the boundary condition on the thermal buckling of the plates are discussed.

Vibration, Buckling and Aeroelastic Analyses of Functionally Graded Multilayer Graphene-Nanoplatelets-Reinforced Composite Plates Embedded in Piezoelectric Layers

2018 ◽  
Vol 10 (03) ◽  
pp. 1850023 ◽  
Author(s):  
H. G. Lin ◽  
D. Q. Cao ◽  
Y. Q. Xu
Keyword(s):  
Applied Voltage ◽  
Composite Plate ◽  
Shear Deformation Theory ◽  
Compressive Force ◽  
Composite Plates ◽  
Graphene Nanoplatelets ◽  
Functionally Graded ◽  
Enhancement Effect ◽  
Multilayer Graphene ◽  
Aerodynamic Pressure

This paper deals with the vibration characteristics and nonlinear aeroelastic response of the functionally graded (FG) multilayer composite plate reinforced with graphene nanoplatelets (GPLs) subjected to in-plane excitations and applied voltage. The different GPL nanofillers distribution patterns across the thickness are discussed, in which the effective Young’s modulus is determined by modified Halpin–Tsai model. Based on high-order shear deformation theory, the motion equations of the FG plate system considering the von Kármán geometric nonlinearity are derived using the Hamilton’s principle. The Galerkin method is applied to discretize the partial differential governing equations into the ordinary differential nonlinear system. The effects of many influential parameters, i.e., GPLs weight fraction, distribution pattern, geometry size, applied voltage and the number of layers, on the vibration and aeroelastic behaviors are presented in detail. Numerical results show that a small amount of GPLs reinforcement can have a significant enhancement effect on the performance of the composite plate structure. Moreover, the in-plane force and aerodynamic pressure play an opposite effect on the dynamic stability, and the jumping phenomena, quasi-periodic motion can be observed with the compressive force increased further.

Effect of High Temperature on Wear Behavior of Stir Cast Aluminium/Boron Carbide Composites

2020 ◽  
Vol 22 (4) ◽  
pp. 1031-1046
Author(s):  
X. Canute ◽  
M. C. Majumder
Keyword(s):  
High Temperature ◽  
Wear Rate ◽  
Boron Carbide ◽  
Wear Behavior ◽  
Base Alloy ◽  
Weight Fraction ◽  
Sliding Velocity ◽  
Wear Properties ◽  
High Temperature Wear ◽  
The Matrix

AbstractThe need for development of high temperature wear resistant composite materials with superior mechanical properties and tribological properties is increasing significantly. The high temperature wear properties of aluminium boron carbide composites was evaluated in this investigation. The effect of load, sliding velocity, temperature and reinforcement percentage on wear rate was determined by the pin heating method using pin heating arrangement. The size and structure of base alloy particles change considerably with an increase of boron carbide particles. The wettability and interface bonding between the matrix and reinforcement enhanced by the addition of potassium flurotitanate. ANOVA technique was used to study the effect of input parameters on wear rate. The investigation reveals that the load had higher significance than sliding velocity, temperature and weight fraction. The pin surface was studied with a high-resolution scanning electron microscope. Regression analysis revealed an extensive association between control parameters and response. The developed composites can be used in the production of automobile parts requiring high wear, frictional and thermal resistance.

Impact Strength, Flexural Modulus and Wear Rate of PMMA Composites Reinforced by Eggshell Powders

2020 ◽  
Vol 38 (7A) ◽  
pp. 960-966
Author(s):  
Aseel M. Abdullah ◽  
Hussein Jaber ◽  
Hanaa A. Al-Kaisy
Keyword(s):  
Impact Strength ◽  
Wear Rate ◽  
Flexural Modulus ◽  
Matrix Material ◽  
Weight Fraction ◽  
Pure Pmma ◽  
Calcination Process ◽  
The Matrix ◽  
The Impact ◽  
Interface Bond

In the present study, the impact strength, flexural modulus, and wear rate of poly methyl methacrylate (PMMA) with eggshell powder (ESP) composites have been investigated. The PMMA used as a matrix material reinforced with ESP at two different states (including untreated eggshell powder (UTESP) and treated eggshell powder (TESP)). Both UTESP and TESP were mixed with PMMA at different weight fractions ranged from (1-5) wt.%. The results revealed that the mechanical properties of the PMMA/ESP composites were enhanced steadily with increasing eggshell contents. The samples with 5 wt.% of UTESP and TESP additions give the maximum values of impact strength, about twice the value of the pure PMMA sample. The calcination process of eggshells powders gives better properties of the PMMA samples compared with the UTESP at the same weight fraction due to improvements in the interface bond between the matrix and particles. The wear characteristics of the PMMA composites decrease by about 57% with increases the weight fraction of TESP up to 5 wt.%. The flexural modulus values are slightly enhanced by increasing of the ESP contents in the PMMA composites.

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