FGM Materials Research Articles

Vibration Control of Tapering E-FGM Porous Wind Turbine Blades Using Piezoelectric Materials

Piezoelectric materials have many interesting applications thanks to their ability to generate an electrical voltage when subjected to mechanical pressure, and vice versa. In the field of vibration energy recovery, these materials can convert mechanical vibrations into electrical energy. For example, piezoelectric sensors integrated into roads or pavements can generate electricity from vibrations caused by vehicles or pedestrians. In the field of wind turbines, the vibratory control of wind turbine blades can increase the overall efficiency of these systems. Additionally, composite materials are being increasingly integrated into the construction of mechanical systems, and specifically FGM materials. This work focuses on the active vibration control of FGM beams with non-uniform cross-sections, using piezoelectric materials. Euler-Bernoulli beam theory combined with the FEM is applied to an FGM beam. The equation of motion is generated using Hamilton's principle.

A Comparison Study on Detailed Strengthening mechanism analysis on micro structure and mechanical properties of 3 phases FGM Material with vibrational behavior analysis is fabricated using WAAM process and traditional method

Additive Manufacturing (AM) techniques implement the surface thickness accumulating through the support of CAD/CAM model for improving the 3D (three dimensional) products. Metal Additive Manufacturing provides design versatility as well as the freedom in fabricating the materials. The preparation technology of the metal composites integrates pressure leaching, agitation casting, powder metallurgy and friction stirring. The strengthening mechanism of the metal composites comprises of ceramic particle, short fiber and whisker etc. The two common strengthening mechanism to attain the high performing material composite are ceramic particulate reinforced composites (CPRCs) and precipitation hardening (PH). Thus, the current study evaluates the strengthening mechanism of fabricated material along with vibrational behavior using Wire Arc Additive Manufacturing (WAAM). The study fabricated three functionally graded material. The FGM materials are SS316L, SS316L+Inconel 625 + Ti6Al4V and SS316L+Inconel 625 + Inconel 718. The three phase FGM material is annealed at 700⁰C, 900⁰C and 1200⁰C for 60 min. Later, it have been air-cooled to the room temperature. The heating process strengthens the three phase FGM materials. The heating process of FGM material results in the precipitation which might not improve the mechanical properties. Nonetheless, the varied annealing temperature such as 900⁰C and 1200⁰C has enhanced the mechanical properties of the three phase FGM materials. As per the analysis, 60 % SS316L+20 % INCONEL 625+20 % Ti6Al4V material has been completely broken whereas 60 % SS316L+20 % INCONEL 625+20 % Inconel 718 has slight crack which show the increased strength of the material. The resonance frequency in conventional part is lower than the AM part. The resonance is oscillated with greater amplitude at certain frequencies. In damping, a higher resonance frequency is less vibrated in common frequencies. Thus, the study concludes that 60 % SS316L+20 % INCONEL 625+20 % Ti6Al4V and 60 % SS316L+20 % INCONEL 625+20 % Inconel 718 has significant strength compared to parent material SS316L. Moreover, AM has better vibration behavior compared to the conventional manufacturing.

Impact of using FGM Materials for Improving the Efficiency of an Internal Combustion Engine

Impact of using FGM Materials for Improving the Efficiency of an Internal Combustion Engine

Evaluation of T-stress in stationary and propagating adiabatic cracks in FGM subjected to thermo-mechanical loading

The aim of this paper is to study the T-stress and its effect on crack propagation in FGM materials with adiabatic cracks subjected to thermo-mechanical loading based on the J-integral formulation and the extended finite element method (XFEM). Path-independent J-integral responses of T-stress for adiabatic cracks and the effects of incompatible terms for FGMs are discussed. Having examined the T-stress parameter, the effect of fracture characteristic/process length on crack propagation angle in adiabatic cracks is studied. The results show that the initial crack propagation angle deviates from the standard propagation angle by increasing the size of the fracture process zone.

A finite element approach for the static and vibration analyses of functionally graded material viscoelastic sandwich beams with nonlinear material behavior

A beam finite element model is proposed for the static and free vibration analyses of FGM sandwich beams with viscoelastic nonlinear material behavior. In the analysis, zigzag theory is adopted for the displacement fields. The damping results from the shear properties of the viscoelastic layer and its low stiffness. Timoshenko 1st order and Reddy’s higher order shear models are implemented for static and vibration behaviors. Various viscoelastic frequency-dependent laws are considered. The resulting stiffness matrix is nonlinear and is frequency dependent. Solutions are possible according to a powerful asymptotic method combined with recent method for the power series terms. The efficiency of the present model is proven through simulations using 3D volume elements of Abaqus code, where new module for viscoelastic FGM materials is now available. The effects of power law index and boundary conditions on static, vibration and the damping properties of the viscoelastic sandwich FGM beam are investigated successfully. It is shown that the beam behavior is very sensitive on the loss factor. In vibration, the damping properties are nonlinearly power law index dependent. The boundary conditions have an incidence on the vibration modes. The cantilever case is particular and interesting that needs an optimization process.

Analysis and sizing of RC beams reinforced by external bonding of imperfect functionally graded plate

An analytical method based on the compatibility of deformations and equilibrium of forces is investigated to predict the reinforcement plate area in concrete beams strengthened with Functionally Graded (FG) plates bonded to the tension face of the beams. The models are given for beams having rectangular and T-crosssections. The effect of porosity that can happen inside FGM materials during their manufacture is also shown. New rules of the mixture that take into account different distribution rates of porosity in FG plates have been developed in this study. A parametric study is conducted to investigate the effect of several parameters such as the ultimate moment, plate stiffness, the distribution rate of the porosity, and compressive strength of the concrete. The results obtained show a significant gain in the reinforcement plate area of the RC beam strengthened with an FG plate relative to another reinforced with FRP plate, which makes it possible to reduce the interfacial stresses and prevents detachment of the reinforcing plate.

Modelling FGM materials. An accurate function approximation algorithms

The study is focused on development of an accurate and cost effective function approximation techniques for modelling functionally graded materials. Different grading functions (exponential, power law) are expanded into Haar wavelet series based on higher order Haar wavelet approach. The proposed techniques can be utilized also for modelling load cases, complex boundary conditions, grading functions etc.

Experimental and Numerical Investigation of Process Parameters on the Residual Stresses in the Al-Cu FGM Materials

Experimental and Numerical Investigation of Process Parameters on the Residual Stresses in the Al-Cu FGM Materials

Vibration and nonlinear dynamic analysis of sandwich FG-CNTRC plate with porous core layer

This paper focuses on the influence of CNTs, porosity, mechanical and thermal loading on the vibration and dynamic response of the sandwich functionally graded carbon nanotube-reinforced composite (FG-CNTRC) composite plate. The plate is made by three layers in which the core layer is porous FGM materials, bottom and top surfaces are FG-CNTRC. The motion equations are given based on Hamilton’s principle, TSDT, Galerkin method and the fourth-order Runge–Kutta method. The numerical illustration is shown to examine the influence of various parameters such as porosity distribution, CNTs volume fraction, geometrical parameters, elastic foundations, temperature, mechanical loads on the dynamic behaviors of the plate. Highlights The FG-CNTRC plates with porous core layer The vibration and nonlinear dynamic analysis Elastic foundation and temperature Analytical solutions, Hamilton’s principle with the high-order shear deflection theory is used Galerkin method and the fourth-order Runge–Kutta method are applied

Nonlinear transient analysis of FG pipe subjected to internal pressure and unsteady temperature in a natural gas facility

This study investigates the response of functionally graded (FG) gas pipe under unsteady internal pressure and temperature. The pipe is proposed to be manufactured from FGMs rather than custom carbon steel, to reduce the erosion, corrosion, pressure surge and temperature variation effects caused by conveying of gases. The distribution of material graduations are obeying power and sigmoidal functions varying with the pipe thickness. The sigmoidal distribution is proposed for the 1st time in analysis of FG pipe structure. A Two-dimensional (2D) plane strain problem is proposed to model the pipe cross-section. The Fourier law is applied to describe the heat flux and temperature variation through the pipe thickness. The time variation of internal pressure is described by using exponential-harmonic function. The proposed problem is solved numerically by a two-dimensional (2D) plane strain finite element ABAQUS software. Nine-node isoparametric element is selected. The proposed model is verified with published results. The effects of material graduation, material function, temperature and internal pressures on the response of FG gas pipe are investigated. The coupled temperature and displacement FEM solution is used to find a solution for the stress displacement and temperature fields simultaneously because the thermal and mechanical solutions affected greatly by each other. The obtained results present the applicability of alternative FGM materials rather than classical A106Gr.B steel. According to proposed model and numerical results, the FGM pipe is more effective in natural gas application, especially in eliminating the corrosion, erosion and reduction of stresses.

Modeling the Capillary Pressure for the Migration of the Liquid Phase in Granular Solid–Liquid–Vapor Systems: Application to the Control of the Composition Profile in W-Cu FGM Materials

A model is developed to compute the capillary pressure for the migration of the liquid phase out or into a uniform solid–liquid–vapor system. The capillary pressure is defined as the reduction of the overall interface energy per volume increment of the transferred fluid phase. The model takes into account the particle size of the solid particle aggregate, the packing configuration (coordination number, porosity), the volume fractions of the different phases, and the values of the interface energies in the system. The model is used for analyzing the stability of the composition profile during processing of W-Cu functionally graded materials combining a composition gradient with a particle size gradient. The migration pressure is computed with the model in two stages: (1) just after the melting of copper, i.e., when sintering and shape accommodation of the W particle aggregate can still be neglected and (2) at high temperature, when the system is close to full density with equilibrium particle shape. The model predicts well the different stages of liquid-phase migration observed experimentally.

Radial Body Forces Influence on FGM and Non-FGM Cylindrical Pressure Vessels

This study deals with the influence of radial body forces on FGM and non-FGM pressure vessels. It contains an extended overview of pressure vessels made from both kinds of material. Furthermore, full mathematical development of stress-strain field for both kinds of cylindrical vessels while being influenced by body forces has been performed. In addition, a new power law model for FGM materials was suggested and discussed. Finally, tables of composed plastic-elastic states are discussed.

Modeling the effects of material properties on the pull‐in instability of nonlocal functionally graded nano‐actuators

Dynamic pull‐in behavior of nonlocal functionally graded nano‐actuators by considering Casimir attraction is investigated in this paper. It is assumed that the nano‐bridge is initially at rest and the fundamental frequency of nano‐structure as a function of system parameters is obtained asymptotically by Iteration Perturbation Method (IPM). The effects of actuation voltage, nonlocal parameter, properties of FGM materials and intermolecular force on the dynamic pull‐in behavior are studied. It is exhibited that two terms in series expansions are adequate to achieve the acceptable approximations for fundamental frequency as well as the analytic solution. Comparison between the obtained results based on the asymptotic analysis and the reported experimental and numerical results in the literature, verify the effectiveness of the asymptotic analysis.

Dynamic instability analysis of electrostatic functionally graded doubly-clamped nano-actuators

This paper is dedicated to investigate the dynamic instability of functionally graded nano-bridges considering Casimir attraction and electric filed actuation. The nano-bridge is initially at rest and actuated by suddenly DC voltage. The fundamental frequency of the system is obtained asymptotically by employing modern approach namely Parameter Expansion Method (PEM). The effects of actuation voltage, properties of FGM materials and intermolecular force on the dynamic pull-in behavior are studied. It is exhibited that in order to achieve the acceptable approximations for fundamental frequency as well as the analytic solution, six terms in series expansions should be taken into account. Comparison between the obtained results based on the asymptotic analysis and the reported results in the literature, verify the strength of the analytical procedure. Finally, the influences of applied voltage and gradient power of functionally graded materials on the dynamic pull-in voltage and pull-in time of vibrating nano-actuators are explained.

Mixed mode fracture analysis of adiabatic cracks in homogeneous and non-homogeneous materials in the framework of partition of unity and the path-independent interaction integral

In this paper, the path independent interaction integral has been implemented in the framework of the extended finite element method for mixed mode adiabatic cracks under thermo-mechanical loadings particularly in orthotropic non-homogenous materials. The mesh insensitivity and increased accuracy due to the thermal and displacement asymptotic analytical solutions are discussed and the contour independency of the interaction integral is investigated in different examples. Finally, the problem of crack propagation in orthotropic FGM materials under the thermal loading is investigated to assess the accuracy and robustness of proposed approach.

Microstructure and Mechanical Properties of Graded Materials Prepared by Field-Activated and Pressure-Assisted Combustion Synthesis

Using the processes of field-activated and pressure-assisted combustion synthesis (FAPACS), FGM materials (FGMs) were prepared under the conditions of field-assisted and the hot-press. The microstructure and the phase composition of the interface of the graded materials were investigated and the results showed that the metallurgical joining layer was formed in the interfaces of the (TiB2)pNi/Ni3Al/405 steel. The mechanical characterization of the gradient materials showed that the composition and the micro-hardness of the gradient material were gradient distributed, and its surface Rockwell hardness and wear resistance are better than that of hardened 20Cr steel.

Ceramic nanolaminates—Processing and application

The self-propagating high-temperature synthesis (SHS) has been used in authors’ works for preparation of ceramic nanolaminates, namely Ti 3SiC 2, Ti 3AlC 2 and Ti 2AlN. The possibility of obtaining near-single-phase materials, processing of SHS products into sinterable powders and densification of the powders by sintering and hot-pressing are discussed. Finally, polycrystalline nanolaminate materials with controlled phase composition and microstructure have been obtained. The materials have been investigated as structure materials by testing their mechanical properties. The possibility of using of prepared powders to obtain ceramic composites, ceramic bonds and FGM materials, as well as their potential application are discussed.

Thick Plate-Shaped Al<sub>2</sub>O<sub>3</sub>/ZrO<sub>2</sub> Composites with Continuous Gradient Processed by Electrophoretic Deposition

This paper concerns the processing of free standing objects with a gradient composition. The possibility to shape 5 mm thick ZrO2-Al2O3 FGM discs by means of electrophoretic deposition (EPD) from suitable stable suspensions was explored. The EPD processing parameters and sintering schedules are described, and the densified FGM composites are evaluated. A mathematical model was established for the EPD process, allowing to calculate the composition gradient in plate-shaped FGM materials from the starting composition of the suspensions, the EPD operating parameters and the powder specific EPD characteristics. The model was essential to engineer the gradient profiles in the green deposits. Defect free Al2O3/ZrO2 FGM discs with a diameter of 55 mm and a thickness of 5 mm could be successfully processed.

Effects of FGM materials on the parametric resonance of plate structures

The parametric resonance of functionally graded rectangular plates under harmonic in-plane loading is presented. The objective here is to study the influence of the constituent volume fractions and the effects of configurations of the constituent materials on the parametric instability regions, in particular the positions and sizes of these regions. The material properties are graded in the thickness direction according to a material volume fraction power law distribution. The present problem is formulated based on Hamilton’s principle and the assumed mode method. Bolotin’s method is used here to determine the instability regions.