Material Properties Of Plate Research Articles

Influence of porosity distribution on free vibration and buckling analysis of multi-directional functionally graded sandwich plates

In this article, the free vibration and buckling of multi-directional porous FGM sandwich plates are investigated. The material properties of FGM sandwich plates are assumed to be varying continuously in the longitudinal and transverse direction. The material properties are evaluated based on Voigt’s micro-mechanical model considering power law distribution method with arbitrary power index. Equilibrium equations for the vibration and buckling analysis of porous multi-directional FGM sandwich plate are obtained based on sinusoidal shear deformation theory. Analytical solution for simply supported multi-directional porous FGM sandwich plate is carried out using Navier’s solution technique. The FGM sandwich plate considered in this work has a homogeneous ceramic core and two functionally graded face sheets. To incorporate porosity in the FGM face sheet, even, uneven, logarithmic uneven, linear uneven, and sinusoidal uneven porosity distribution models are considered and analyzed. Influence of volume fraction index in the longitudinal and transverse direction, layer thickness, porosity models, porosity coefficient, and geometrical parameter over natural frequency and critical buckling load of multi-directional FGM sandwich plate is investigated.

Free vibration analysis of imperfect functionally graded sandwich plates: analytical and experimental investigation

Purpose: This paper develops a new analytical solution to conduct the free vibration analysis of porous functionally graded (FG) sandwich plates based on classical plate theory (CPT). The sandwich plate made of the FGM core consists of one porous metal that had not previously been taken into account in vibration analysis and two homogenous skins. Design/methodology/approach: The analytical formulations were generated based on the classical plate theory (CPT). According to the power law, the material properties of FG plates are expected to vary along the thickness direction of the constituents. Findings: The results show that the porosity parameter and the power gradient parameter significantly influence vibration characteristics. It is found that there is an acceptable error between the analytical and numerical solutions with a maximum discrepancy of 0.576 % at a slenderness ratio (a/h =100), while the maximum error percentage between the analytical and experimental results was found not exceeding 15%. Research limitations/implications: The accuracy of analytical solutions is verified by the adaptive finite elements method (FEM) with commercial ANSYS 2020 R2 software. Practical implications: Free vibration experiments on 3D-printed FGM plates bonded with two thin solid face sheets at the top and bottom surfaces were conducted. Originality/value: The novel sandwich plate consists of one porous polymer core and two homogenous skins which can be widely applied in various fields of aircraft structures, biomedical engineering, and defense technology. This paper presents an analytical and experimental study to investigate the free vibration problem of a functionally graded simply supported rectangular sandwich plate with porosities. The objective of the current work is to examine the effects of some key parameters, such as porous ratio, power-law index, and slenderness ratio, on the natural frequencies and damping characteristics.

Influence of porosity distribution on static and buckling responses of porous functionally graded plates

This article studies the effect of porosity distribution on static and buckling response of a functionally graded (FG) porous plate with all its four edges simply supported and subjected to a transverse load. The plate’s displacement field is approximated based on an inverse hyperbolic shear deformation theory (IHSDT) involving five variables. In this theory, inplane displacements vary as an inverse hyperbolic function through the plate thickness, so account for non-linear variation of transverse shear stresses and satisfies traction free boundary conditions on the surfaces of plate without the need of any shear correction factors. The governing equations of motion are derived using the principle of virtual work, and thus, the expressions of its strain energy and work done are obtained. Effective material properties of porous plate are assumed with an additional term of porosity in the direction of thickness. Power-law is used for continuous variation of material properties along the thickness direction. In this study, five types of porosity distribution functions are considered. The effect of the porosity parameter, the power-law exponent, side-thickness ratio, and aspect ratio on the static and buckling responses of the porous FG plate is evaluated. In problem-solving, the Navier solution technique is used to obtain the exact solutions. The non-dimensional deflections and critical buckling loads of FG porous plate are thus obtained. The results are compared with available results in the literature, and good agreement is found. Moreover, the results are presented to study the effects of various parameters on the dimensionless deflections, stresses, and critical uni-axial and bi-axial buckling loads.

Guided wave propagation of porous functionally graded plates: The effect of thermal loadings

Because there is no literature on the effect of thermal loadings on guided wave propagation in FG plates, the present paper is to fill the gap. In the present paper, the wave propagation analysis of porous FG plates with clamped ends in thermal environments based on first order shear deformation theory are presented. The plates are exposed to various types of thermal loading including uniform and non-uniform temperature changes, the material properties of FG plates are temperature- and porosity-dependent. Using the Galerkin method, we obtain the dispersion relation of thermoelastic waves in porous functionally graded plates. Compared with the previous results, the correctness of the present work is verified. In the end, the effects of the temperature changes, porosity as well as power law index on the phase velocity and group velocity of the guided wave are investigated.

Simulation Analysis of Void Defect Detection in Sandwich-Structured Immersed Tunnel Using Elastic Wave

Void defects can be easily generated between a steel plate and concrete joint due to the complicated internal structure of a sandwich-structured immersed tunnel (SSIT), which affect the overall bearing capacity of the main structure of the immersed tube tunnel. A prototype experiment was conducted to study the application of impact imaging method in the nondestructive detection of void defects in SSITs. The detection criterion for the impact imaging method was established based on the features of the waveform data. Nevertheless, the influence of steel plate thickness, material properties, void location, and structure on the detection accuracy of the impact imaging method is unclear. Therefore, numerical simulation was applied to study the influencing factors by establishing a different condition model. Good agreement between the experimental and numerical results was observed for the response waveform collected from the inspection area. Using the calculation model and identified material parameters validated in the active prototype experiment, numerical simulations of several sets, which considered all influencing factors, were performed. The application scope and sensitivity of the impact image method were recommended to reduce misjudgement in practical applications and improve detection accuracy.

Analysis of carbon nanotube reinforced composite plate using finite element method with higher order zigzag theory

ABSTRACT Static investigation of slim to tolerably thick composite plate built up by single-walled cabon nanotubes (CNT) is examined utilising the limited component technique dependent on higher order zigzag theory. The efficient material properties of nanocomposite plate have been dictated by the rule of mixture. It is seen that there are no outcomes accessible in the open writing on static investigation of nanocomposite plate dependent on refined theories. Point-by-point parametric investigations have been conveyed to uncover the impacts of the volume parts of the CNT, the edge to thickness proportions and different edge conditions on the bending behaviour of plate. To approve the current examination, some mathematical outcomes were compared with those accessible in the open literature, thus numerous outcomes have been created for future reference.

Influence of the plate thickness and material properties on the violin top plate modes

In this paper we analyze the vibrational behavior of the violin top plate, for varying plate thickness and material properties via finite element method (FEM) numerical simulations. It is well known that the vibrational properties of the top plates of string instruments influence their sound emission characteristics. Due to the impact of global warming on wood formation and due to their configurability, many manufacturers investigate the use of composite materials to produce musical instruments. Therefore, composite, carbon fiber reinforced epoxy (CFRE) prepreg along with traditional wooden material, such as spruce, are adopted in this study. FEM modal analysis along with a frequency response function (FRF) FEM analysis are performed. The vibrational variations of the plate's response are computed under free conditions. The main vibrational modes and the natural frequencies obtained by the simulations show the influence of the different mechanical and geometric properties on the top plate's vibrational response. The resulting eigenmode frequencies and shapes of the plate in relation to the varying thickness and the material properties used, are discussed. The results of this study offer valuable information on the evaluation of the acoustical characteristics of violins and may be further used on their vibrational behavior optimization and control.

Investigation of Corrosion Performance of Pure Aluminum as Bipolar Plate in PEMFC Environment

The global climate changes occurred because of the emissions of greenhouse gases such as CO2, NO x and SO x that are ongoing throughout the world pose a gradually higher demand for replacing today's fossil fuel based energy system by less pollutant technologies.[1-2] Among the alternative energies available, proton exchange membrane fuel cells (PEFCs) have been considered to power transportation vehicles such as automobiles and buses due to their high power density, relatively quick start-up and low operating temperatures.[3] The bipolar plate is one of the most important parts that impacts the manufacturing cost of the PEFC.[4] The high electrical conductivity, high gas impermeability, good mechanical performance and low cost are some of the desired properties of bipolar plate materials. Also, mainly two types of materials are used as bipolar plates in PEFC as carbon and metals. Carbon materials show a very good corrosion resistance but lower performance in separating reaction gases compare with metals. Among the many candidate materials, aluminum (Al) is considered as better bipolar plate applications in PEFC due to its low cost and low density.[5] Moreover, bipolar plate is required to have sufficient corrosion resistance even with a sulfuric acid solution having a pH of around 3.0, but it is considered that Al cannot tolerate this condition without its well surface modification which is proposed by Yashiro et al.[6] Sulfuric acid solutions are widely used for aluminum anodizing operations. That’s why it was our interest to study the corrosion of Al material for using as a gas separating plate in PEFC environment. Also, the influence of sulfate and fluoride ions on the stability of films formed on Al surfaces in aqueous solutions of sulfuric acid and sodium fluoride particularly at low concentration levels through finding the amount of corrosion was examined. Scanning electron microscopic (SEM), energy dispersive x-ray (EDX) and cross-sectional analyses were also done to observe the surface morphology and elemental composition.In the present investigation, pure Al having 6 cm2 of area were used as the test pieces for immersion in 2.5×10-6M H2SO4 (pH 5.41), 5×10-6M H2SO4 (pH 5.14), 2.5×10-6M H2SO4 + 2ppm F- (pH 5.57) and 5×10-6M H2SO4 + 2ppm F- (pH 5.45) solutions using reagent grade of H2SO4 and NaF. Test pieces were polished by emery paper 4/0, 6/0, 1200 and 2000, rinsed and immersed in around 100 cm3 aqueous solutions for a period of 24h, 48h, 72h, 96h and 120h at 80°C. A potentiodynamic polarization test was performed to check the corrosion resistance of Al in the simulated PEFC environment using 0.05M SO4 2- and 2ppm F- solutions (pH 3.3 and 5.8) and high current density of Al was found. Moreover, a 500h single cell operation was also performed to investigate the corrosion of Al as the gas separating plates. A glassy carbon was used as the channel former and aluminum foil was used as the gas separating plate. The single cell results showed that the corrosion of the gas separation plate was much milder than the corrosion expected in polarization test which showed the possibility of using Al as a gas separating plate in PEFC.Additionally, the oxide film was formed in the Al surfaces because of the oxidized aluminum at the time of immersion. As a result, the corrosion products were formed and graphed as amount of corrosion versus immersion time. Firstly, the amount of corrosion was increased with increasing the concentration of sulfuric acid and increased more after the addition of 2ppmF- ions in the acid solutions. From the results found in this study, it is concluded that pure as-polished Al undergoes severe corrosion in sodium fluoride whereas sulfate ions form much lower corrosion as well as act as inhibitor when Al is used as bipolar plate in the PEFC environment. Acknowledgements This work was supported by the Ministry of Education, Sports, Science and Technology (MEXT), Japan. References Carrette, K. A. Friedrich, U. Stimming, Fuel Cells, 1 (1), 5-39 (2001).O. Collantes, Technol Forecasting Soc. Change, 74(3), 267-280 (2007).Schäfer, J. B. Heywood, M. A. Weiss, Energy, 31 (12), 2064-2087 (2006).Cunningham, D. Baird, J. Mater. Chem, 16, 4385-4388 (2006).A. A. El-Enim, O. E. Abdel-Salam, H. El-Abd, A. M. Amin, J. Power Sources, 177 (1), 131-136 (2008).Yashiro, T. Ichikawa, S. -T. Myung, M. Kumagai, S. Kozutsumi, Zairyo-to-Kankyo, 60 (10), 432-434 (2011).

Efficient Theoretical and Numerical Methods for Solving Free Vibrations and Transient Responses of a Circular Plate Coupled With Fluid Subjected to Impact Loadings

Abstract This paper presents an easy-to-use theoretical method and an efficient numerical method for solving free vibrations and transient responses of a circular plate coupled with fluid subjected to impact loadings and provides insights into various coupling cases with these developed methods. The Kirchhoff plate theory, Mindlin–Reissner plate theory, and the linear velocity potential function are used. The wet mode of the coupled system is described as the superposition of dry modes of the plate, which has been considered in few studies. The natural frequencies and corresponding mode shapes are solved using the orthogonality of dry modes. The transient responses of the plate are then solved using the superposition of the wet modes and the orthogonality of dry modes. To validate the theoretical results, an efficient and flexible finite element method is proposed and verified by comparing with commercial software. The four-node mixed interpolation of the tensorial component quadrilateral plate finite element (MITC4) and the eight-node acoustic pressure element are used to model the plate and the fluid, respectively. The theoretical and numerical methods provide reliable and accurate results. Parametric studies are performed to investigate the influence of geometric sizes, plate material properties, and fluid properties on the natural frequencies of the coupled system. A coupling parameter of fluid–structure interaction is proposed. The nondimensional added virtual mass incremental (NAVMI) factor decreases as the coupling parameter increases. Besides, the influence of fluid on wet modes of the plate decreases with the order.

Free vibration analysis of FGM plates on Winkler/Pasternak/Kerr foundation by using a simple quasi-3D HSDT

This paper introduces a simple quasi-3D theory with Reddy shear function and a new trigonometric shear function to conduct free vibration analysis of the functionally graded plates resting on Winkler/Pasternak/Kerr elastic foundation. The proposed transverse shear strain functions satisfy the stress-free boundary conditions on the surfaces of the functionally graded plate without using any shear correction factors. The governing differential equation and boundary conditions are derived based on Hamilton's principle and Winkler/Pasternak/Kerr type mathematical model. The material properties of FGM plates discussed in this paper are assumed to vary through the thickness according to the power-law distribution. The obtained results are compared with other 2D, quasi-3D and exact 3D solutions. The results show that the proposed trigonometric shear functions are more accurate than Reddy ones. Some interesting physical discussions of the recorded results are also given in this study.

Part 1. Review and meta-analysis of studies on modulation of longitudinal bone growth and growth plate activity: A macro-scale perspective.

Growth modulation is an emerging method for treatment of angular skeletal deformities such as adolescent idiopathic scoliosis (AIS). The Hueter-Volkmann law, by which growth is stimulated in tension and inhibited in compression, is widely understood, and applied in current growth-modulating interventions such as anterior vertebral body tethering (AVBT) for AIS. However, without quantification of the growth rate effects of tension or compression, the possibility of under- or over- correction exists. A definitive mechanical growth modulation relationship relating to treatment of such skeletal deformities is yet to exist, and the mechanisms by which growth rate is regulated and altered are not fully defined. Review of current literature demonstrates that longitudinal (i.e., lengthwise) growth rate in multiple animal models depend on load magnitude, anatomical location, and species. Additionally, alterations in growth plate morphology and viability vary by loading parameters such as magnitude, frequency, and whether the load was applied persistently or intermittently. The aggregate findings of the reviewed studies will assist in work towards increasingly precise and clinically successful growth modulation methods. Part 1 of this review focuses on the effects of mechanical loading, species, age, and anatomical location on the macro-scale alterations in longitudinal bone growth, as well as factors that affect growth plate material properties. Part 2 considers the effects on micro-scale alterations in growth plate morphology such as zone heights and proportions, chondrocyte viability, and related gene and protein expression.

Higher order plate theory for buckling analysis of plates based on exact solution

In this paper, buckling analyses of composite plate reinforced by Graphen platelate (GPL) is studied. The Halphin-Tsai model is used for obtaining the effective material properties of nano composite plate. The nano composite plate is modeled by Third order shear deformation theory (TSDT). The elastic medium is simulated by Winkler model. Employing nonlinear strains-displacements, stress-strain, the energy equations of plate are obtained and using Hamilton's principal, the governing equations are derived. The governing equations are solved based on Navier method. The effect of GPL volume percent, geometrical parameters of plate and elastic foundation on the buckling load are investigated. Results showed that with increasing GPLs volume percent, the buckling load increases.

Nonlinear forced vibration of in-plane bi-directional functionally graded materials rectangular plate with global and localized geometrical imperfections

This research aims to investigate the nonlinear vibration of the in-plane bi-directional functionally graded (BDFG) plate with global and localized geometrical imperfection subjected to a transverse harmonic excitation. The material properties of plate are varying along two in-plane directions. The global and localized geometrical imperfections are simulated in the form of products of trigonometric and hyperbolic functions. Based on the von Kármán’s nonlinear plate theory, coupled nonlinear partial differential equations governing in-plane and transverse displacements of BDFG plate are derived employing Hamilton’s principle. The continuous nonlinear model of imperfect BDFG plate is discretized using the Galerkin scheme, resulting in the reduced order model. The pseudo-arclength continuation technique is employed to trace the periodic motion of plate and construct frequency-/force-response curves. Dynamic responses are solved using numerical integration. Numerical results of ceramic-metal BDFG plates are presented to examine the effects of system parameters, e.g. functional gradient parameters, external excitation parameters and damping coefficients. Particularly, influences of global and localized geometrical imperfections are highlighted. Results show that the variation of gradient parameter and the existence of geometrical imperfection change the nonlinearity of resonant response. Cyclic-fold, period doubling and torus bifurcations of the periodic solution are detected as excitation parameters varying. Periodic, quasi-periodic and chaotic motions of plate are also explored.

The Linear and Nonlinear Bending Analyses of Functionally Graded Carbon Nanotube-Reinforced Composite Plates Based on the Novel Four-Node Quadrilateral Element

This paper presents the linear and nonlinear analyses of functionally graded carbon nanotube- reinforced composite (FG-CNTRC) plates using a four-node quadrilateral element based on the C0-type of Shi’s third-order shear deformation theory (C0-STSDT). Shi’s theory is taking the advantages and desirable properties of the third-order shear deformation theory. Besides, material properties of FG-CNTRC plates are changed from the bottom to top surface and based on the rule of mixture. Numerical results and comparison with other reference solutions suggest that the advantages of present element are accuracy and efficiency in analysis of FG-CNTRC plates. Some nonlinear numerical results of FG-CNTRC plates are also given in this paper and this contributes to providing additional data for future research work.

Buckling analysis of functionally graded materials by dynamic approach

Laminated composites exhibit difference in the mechanical properties at the interface between two materials resulting in stress concentration. This may lead to damages in the form of delamination, matrix cracking and adhesive bond separation. Functionally Graded Materials (FGM) are formed by gradual variation of two or more material over a particular volume, thereby overcomes these issues. Buckling problems of FGM plates are usually solved by static approach. In some cases, particularly non-uniform loading and geometric discontinuity, the stress concentration usually occurs. In such cases, the solution to the buckling problem by dynamic approach is most suitable. In the dynamic approach, the natural frequencies are calculated by applying in-plane loads. As the intensity of the in-plane load increases, the frequency of the material decreases and finally becomes zero at the onset of buckling. The load at which the natural frequency becomes zero that load is called a buckling load. In this investigation, the vibration and buckling characteristics of FGM panels subjected to uniaxial and biaxial loading conditions have been studied by using the finite element method (F.E.M). In the Finite element (FE) formulation, the effective material properties of FGM plates are assumed to vary in the thickness direction according to the power-law distribution of volume fraction of the constituents. The plate is modelled by using 8-noded serendipity element by incorporating the effect of transverse shear deformation and rotary inertia. The effect of different parameters such as volume fraction index (n), the thickness of the panel (h) and boundary condition of the plate are considered to study the buckling behaviour of the FGM plate under uniaxial loading conditions.

Free vibration of functionally-graded porous cracked plates

This paper is focused on predicting the natural frequency of a simply-supported, functionally-graded material (FGM) plate with even porosity distribution and a side surface crack. First, an analytical solution is obtained for the free vibration of a simply-supported porous FGM plate. The power law is used to describe the material properties of the porous FGM plate through the thickness. Hamilton's principle is used to derive the equations of motion of the FGM plate with third-order shear deformation plate theory. Navier's solution is used to solve the problem. The effects of porosity and material distribution parameters on the natural frequency of the FGM plate are discussed. Then, the results obtained from this study are validated and compared with results available in literature. Second, the Artificial Neural Network (ANN) technique is used to predict the natural frequency variations of porous FGM plates with a side surface crack, based on more than 2,500 data points collected from the analytical solution obtained in this paper as well as some from existing literature. The ANN technique allows for investigation of the effects of various parameters, including plate characteristics, material properties, geometric details, crack location, and porosity distribution. Finally, by performing both network and computational analysis, it is proven that porosity distribution in the presence of cracks affects the natural frequency of the FGM plates. For the first time, accurate, non-dimensional frequency data are provided for simply–supported, cracked, porous Al/Al2O3 and Si3N4/SUS304 FGM plates. The ANN model shows that it is a powerful technique capable of handling a large database, various key parameters, and material nonlinearity.

Buckling analysis of actuated functionally graded piezoelectric plates via a quasi-3D refined theory

The electro-mechanical buckling response for functionally graded piezoelectric plates subjected to external electric voltage is analyzed based on a quasi-3D refined plate theory. The plate material properties possess continuous graded variation across the thickness based on the power-law form. The total potential energy principle is used to obtain the equilibrium equations. Navier's procedure is applied to derive the solution for the buckling of a simply supported functionally graded piezoelectric plate. A numerical example is presented to validate the accuracy of the present analysis. The critical buckling of actuated FGP plates is determined. The influence of external electric voltage, the geometry of the plate, and material exponent on the critical buckling are reported.

Acoustic analysis of functionally graded porous graphene reinforced nanocomposite plates based on a simple quasi-3D HSDT

The sound radiation and sound transmission loss (STL) characteristics of functionally graded porous graphene reinforced nanocomposite plates (FG-PGRC) are investigated based on a simple quasi-3D high order shear deformation theory (HSDT) considering bending, shear and thickness stretching effects. The Gaussian Random Field scheme theory and Halpin-Tsai micromechanical model are used to estimate the material properties of FG-PGRC plates. The governing equations are derived based on Hamilton's principle. The sound radiation and sound transmission loss of FG-PGRC plates are obtained via modal theory and Rayleigh integral method. The effects of GPL and porosity distribution patterns, weight fraction of GPLs, porosity coefficient, thickness to width ratio, damping, temperature and incidence angle on acoustic properties of FG-PGRC plates are analyzed. Results indicate that the acoustic characteristics of FG-PGRC plates are significantly influenced by above parameters. Proper design of relevant parameters can improve the acoustic characteristics of FG-PGRC plates.

Free vibration analysis of FG-CNTRC conical shell panels using the kernel particle Ritz element-free method

The free vibration analysis of functionally graded carbon nanotube reinforced composite (FG-CNTRC) conical shell is carried out by using element-free kp-Ritz method. Based on the first-order shear deformation shell theory, the approximate displacement field is expressed by the shape function of the nuclear particle, and the governing equation is established. The material properties of conical shell plates are determined by rule of mixtures and change with the thickness. In this work, the convergence is studied in terms of the number of nodes, and the accuracy of the proposed method is verified by comparing the current solution with the solution in the literature from different aspects. The effects of volume fraction, boundary conditions, distribution patterns of CNTs, half vertex angle and radius thickness ratio on their free vibration frequency characteristics are discussed in detail.

Preparation and application of unfired Al2O3–Al–C slide plate materials in the presence of trace Zn

The unfired Al2O3–Al–C slide plates were prepared using tabular alumina aggregates and fines, Al powder and graphite powder as starting materials, and phenol formaldehyde resin as binder. The effects of trace Zn on properties and microstructure of samples at elevated temperatures were investigated. Post mortem investigations on the newly developed Al2O3–Al–C slide plates with trace Zn were carried out. The results showed that the properties of the unfired slide plate materials at low temperature (500–700 °C) were remarkably enhanced in presence of trace Zn, and the high temperature properties above 1000 °C of the slide plates with Zn were also greatly improved in comparison to the conventional ones. After used in 90 t ladles for 2 consecutive heats, the bore enlargement of the newly developed slide plates was less than 2 mm/heat, and roughening on the sliding surface was slight, showing good high temperature service performance. The improved properties were attributed to the high reactive Zn reacting with O2 or CO to form ZnO ceramic phase and protected phenolic resin from oxidation at low temperature, and the vaporized Zn could promote non-oxide Al4C3 and AlN formation and growth at high temperature, creating strengthening and toughening effects.