جستجوی مقالات مرتبط با کلیدواژه « Sector plates » در نشریات گروه « مکانیک »

In this research, aerodynamic and vibrational behaviors of sector plates made from metal foams reinforced by graphene nanoplatelets are considered. Metal foams are a new and advanced branch of porous materials and their main advantage is their high stiffness to density ratio. Although due to their lightweight, metal foams are welcomed nowadays, this causes a decrease in their strength and is one of their main weaknesses that by adding nanoparticles, this weakness is eliminated. Today, graphene nanoplatelets are known as one of the best reinforcements. Under Gaussian random field for closed-cell cellular solids, the effective properties of the matrix are obtained and by employing two Halpin-Tsai and rule of mixture micromechanical models, elasticity modulus and other mechanical properties of the plate are determined. Pores distribution and also graphene nanoplatelets dispersion through the thickness direction, each is based on three different patterns and their effect on the vibrational behavior of the under consideration model is observed. With the aid of the variational approach and Hamilton’s principle, the governing equation and associated boundary conditions are derived and solved numerically, and the effect of different parameters such as pores distribution, nanoparticles dispersion and other important parameters on the results is discussed.

In this paper, free vibration analysis of two-dimensional functionally graded annular sector plates with two piezoelectric layers on elastic foundation using the Rayleigh-Ritz method is investigated applying the third order shear deformation theory of plates. Despite the existence of more complex equations, the third-order shear deformation theory of plates leads to more accurate results, this is due due to the effects of transverse shear deformation and inertial rotation,.The material properties of the annular plate is graded two-dimensionally in both of the circumferential and thickness directions. The volume fraction power law distribution is used to model the two dimensional functionally graded plate properties. The sinusoidal function is used to determine the electrical potential of the piezoelectric layers. The assumed potential function satisfies the Maxwell electrostatic equations. To obtain the natural frequencies of the plate, the Lagrangian function is defined by subtracting the kinetic and potential energies of the plate and then the Hamilton’s principle and the Ritz method is applied to obtain the natural frequencies of the plate. Finally, the results are validated by various references and the effect of various parameters including the sector angle, ratio of thickness to radius of the plate and foundation coefficients on the natural frequency of the structure has been discussed.

In this study, free vibration analysis of isotropic sector plates coupled with piezoelectric layers based on first-order shear deformation theory has been analyzed. Governing differential equations of the dynamic behavior of free vibration of isotropic sector plates coupled with piezoelectric layers are derived using Hamilton's principle and the electrostatic Maxwell equations. The Coupled governing differential equations of the vibrating composite plate are solved by applying the method of separation of variables and auxiliary potential functions. The presented analytical exact solution in this paper is validated with available data in the literature. Using numerical results the effect of opening angle of sector plate , the host thickness to radius ratios , inner to outer radius ratios , the ratio of thickness of the piezoelectric layer respect to thickness of the host plate and different boundary conditions on the natural frequencies of the vibrating sector plates coupled with piezoelectric layers are obtained. Also impact, manner and conditions of each parameter on the natural frequencies areconsidered and discussed.

Abstract - In this article, thermal buckling analysis of functionally graded annular sector plate is studied. The mechanical and thermal properties of the functionally graded sector plate are assumed to be graded in the thickness direction. The equilibrium and stability equations are derived based on the first order shear deformation plate theory (FSDT) in conjunction with nonlinear von-karman assumptions. Differential quadrature method is used to discretize the equilibrium and stability equations. In this method a non-uniform mesh point distribution (Chebyshev-Gauss-Lobatto) is used for provide accuracy of solutions and convergence rate. By using this method, there is no restriction on implementation of boundary conditions and various boundary conditions can be implemented along any edges. Finally, The results compared with other researches and the effects of plate thickness, sector angle, annularity, power law index and various boundary conditions on the critical buckling temperature are discussed in details.