Porous Annular Plates Research Articles

Vibration characteristics of FG saturated porous annular plates integrated by piezoelectric patches on visco‐Pasternak foundation

AbstractThe vibrational behavior of a three‐layered annular plate is considered in the present study. The plate is composed of a functionally graded (FG) porous core which is saturated by fluid and two piezoelectric patches that are bonded to the core and are subjected to the electric field. The whole of the structure is also rested on visco‐Pasternak elastic foundation. The material properties of the FG porous core vary through the thickness direction based on different patterns which are called porosity distributions. Love‐Kirchhoff's hypothesis and Hamilton's principle is employed to extract the governing motion equations and boundary conditions and following it, they are solved by generalized differential quadrature method (GDQM) for various boundary conditions. After ensuring the validity of the results by comparing them with known data in the literature, the effect of the most important parameters on the results is considered. It is seen that the effect of the porosity coefficient on the natural frequencies is completely dependent on the pores’ distribution patterns. Also, increasing in externally applied voltage to the piezoelectric facesheets, leads the results to enhance. The outcomes of this work can help to design and create smart structures and systems such as sensors and actuators.

Nonlinear dynamics response of porous functionally graded annular plates using modified higher order shear deformation theory

In this investigation, the nonlinear dynamics of porous annular plates that have been functionally graded are examined under varying time-dependent loads. Both simple supported and fully clamped boundary conditions are taken into account. The mechanical properties of the functionally graded plate in its thickness are considered according to the distribution function of the modified law. In addition, porosity, as a stress-relieving property, is also applied throughout the plate thickness by different functions and pore volume fractions. By adopting Hamilton’s principle, the equations of motion are obtained based on the modified higher-order shear deformation plate theory. Then these partial differential equations are solved using the viscous dynamic relaxation method in conjunction with Newmark’s implicit integration method. The present findings are compared and successfully confirmed with those available in the literature. Finally, the effects of some key factors such as porosity distribution type, pore volume fraction, power-law index, loading conditions, and thickness-to-radius ratio on the dynamic behavior of both simple and fully clamped plates have been studied in detail. The study’s findings indicate that porosity pattern X, characterized by a greater prevalence of interconnected pores, exhibited enhanced resistance to deflection. Conversely, pattern O, featuring a more uniformly distributed pore size, effectively mitigated stress in FG porous materials. These observations offer valuable insights for optimizing plate design and elevating its performance.

Magneto-electro-thermo-elastic frequency response of functionally graded saturated porous annular plates via trigonometric shear deformation theory

Magneto-electro-thermo-elastic frequency response of functionally graded saturated porous annular plates via trigonometric shear deformation theory

A unified Jacobi–Ritz approach for the FGP annular plate with arbitrary boundary conditions based on a higher-order shear deformation theory

In this paper, a unified method for free and forced vibration of functionally graded porous annular and circular plate is proposed, incorporating the Jacobi–Ritz method and the higher-order shear deformation theory. In order to improve the accuracy of calculation, the segment strategy is adopted. Meanwhile, the artificial spring is used to express the connection between each truncated plates and arbitrary boundary conditions. The convergency study and validation are implemented, and parametric study of both free and transient forced vibration are conducted. The present method shows a fast convergence property and high accuracy for thick plate. It has been found that boundary conditions are the dominant influencing factor of the central deflection of functionally graded porous annular plate, and the porous material with vertical gradient change in the plate leads to a better impedance effect than the uniformly distributed porous material.

Prediction of the in-plane vibration behavior of porous annular plate with porosity distributions in the thickness and radial directions

A semi-analytical model is proposed in this study to investigate the in-plane vibration behavior of porous annular plate with porosity distributions in the thickness and radial directions. A variational method combined with a multi-segment technique is employed to establish the theoretical model of elastic restrained porous annular plate. Admissible functions of each plate segment are expanded in the mixed series form, that is, the Jacobian orthogonal polynomial for radial variables and Fourier series for circumferential variables. The boundary penalty parameters are introduced to implement different boundary restrictions and the coupling penalty parameters are employed for ensuring the continuity conditions between segments. A series of numerical examples are given to discuss the convergence characteristics and numerical stability of the current model. The comparison between modal tests and numerical predictions shows that good prediction capabilities with acceptable errors are achieved by the proposed method. The influences of geometrical and material parameters on the in-plane vibration characteristics of porous annular plate are also discussed in detail.

Axisymmetric free vibration and stress analyses of saturated porous annular plates using generalized differential quadrature method

The current study presents free vibration and stress analyses of an annular plate which is made of saturated porous materials based on the first order shear deformation plate theory which accounts for the shear deformation effects. The pores are distributed in the thickness direction according to three different types, namely, porosity nonlinear nonsymmetric distribution, porosity nonlinear symmetric distribution, and porosity monotonous distribution. Employing Hamilton’s principle and variational formulation, the motion equations are derived and solved via the generalized differential quadrature method as a highly accurate and rapid convergence numerical method for various boundary conditions. The results are validated with simpler cases in the literature and different parameters of the structures such as pores distribution, porosity, pressure of fluids within the pores, and also the aspect ratio of the plate is considered and discussed regarding their effects on the results. It is seen that enhancing the porosity coefficient which means increasing the void volume, reduces the structure’s stiffness more than its density and so the frequency and stresses decrease. The findings of this work may be useful to design structures with desired mechanical properties.

Combined Effect of Piezoviscous Dependency and Non-Newtonian Couple Stress on Squeeze-Film Porous Annular Plate

Squeeze film investigations focus upon film pressure, load bearing quantity and the minimum thickness of film. The combined effect of pressure viscous dependent and non- Newtonian couple stress in porous annular plate is studied. The modified equations of one dimensional pressure, load bearing quantity, non dimensional squeeze time are obtained. The conclusions obtained in the study are found to be in very good agreement compared to the previous results which are published. The load carrying capacity is increased due to the variation in the pressure dependent viscosity and also due to the couple stress effect. Finally this results in change in the squeeze film timings.

Effect of surface roughness and elastic deformation on the performance of a magnetic fluid-based squeeze film in rotating porous annular plates

Purpose – The purpose of this paper is to study and analyse the behaviour of a magnetic fluid-based squeeze film between rotating transversely rough porous annular plates, taking the elastic deformation into consideration. Design/methodology/approach – The stochastic film thickness characterizing the roughness is considered to be asymmetric with non-zero mean and variance and skewness while a magnetic fluid is taken as the lubricant. The associated stochastically averaged Reynolds-type equation is solved with appropriate boundary conditions to obtain the pressure distribution, which in turn is used to derive the expression for the load-carrying capacity. Findings – It is observed that the roughness of the bearing surfaces affects the performance adversely, although the bearing registers an improved performance owing to the magnetic fluid lubricant. Also, it is seen that the deformation causes reduced load-carrying capacity. The bearing can support a load even in the absence of flow, unlike the case of conventional lubricants. Originality/value – The originality of the paper lies in the fact that the negative effect of porosity, deformation and standard deviation can be minimized to some extent by the positive effect of the magnetic fluid lubricant in the case of negatively skewed roughness by suitably choosing the rotational inertia and aspect ratio. This effect becomes sharper when negative variance occurs.

Magnetic Fluid-Based Squeeze Film Behaviour in Curved Porous-Rotating Rough Annular Plates and Elastic Deformation Effect

Efforts have been directed to study and analyze the squeeze film performance between rotating transversely rough curved porous annular plates in the presence of a magnetic fluid lubricant considering the effect of elastic deformation. A stochastic random variable with nonzero mean, variance, and skewness characterizes the random roughness of the bearing surfaces. With the aid of suitable boundary conditions, the associated stochastically averaged Reynolds' equation is solved to obtain the pressure distribution in turn, which results in the calculation of the load-carrying capacity. The graphical representations establish that the transverse roughness, in general, adversely affects the performance characteristics. However, the magnetization registers a relatively improved performance. It is found that the deformation causes reduced load-carrying capacity which gets further decreased by the porosity. This investigation tends to indicate that the adverse effect of porosity, standard deviation and deformation can be compensated to certain extent by the positive effect of the magnetic fluid lubricant in the case of negatively skewed roughness by choosing the rotational inertia and the aspect ratio, especially for suitable ratio of curvature parameters.

A study on the performance of a magnetic fluid based squeeze film in curved porous rotating rough annular plates and deformation effect

Efforts have been made to analyze the behaviour of a magnetic fluid based squeeze film between rotating transversely rough porous annular plates incorporating elastic deformation. The results suggest that the roughness of the bearing surfaces affects the performance adversely although; the bearing registers an improved performance owing to the magnetic fluid lubricant. It is seen that the deformation causes reduced load carrying capacity. This investigation reveals that the negative effect of porosity, deformation and standard deviation can be minimized up to certain extent by the positive effect of the magnetic fluid lubricant in the case of negatively skewed roughness.