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panel-flutter
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Chaotic analysis of nonlinear viscoelastic panel flutter in supersonic flow
, Article Nonlinear Dynamics ; Volume 32, Issue 4 , 2003 , Pages 387-404 ; 0924090X (ISSN) ; Fazelzadeh, S. A ; Sharif University of Technology
2003
Abstract
In this paper chaotic behavior of nonlinear viscoelastic panels in a supersonic flow is investigated. The governing equations, based on von Kàrmàn's large deflection theory of isotropic flat plates, are considered with viscoelastic structural damping of Kelvin's model included. Quasi-steady aerodynamic panel loadings are determined using piston theory. The effect of constant axial loading in the panel middle surface and static pressure differential have also been included in the governing equation. The panel nonlinear partial differential equation is transformed into a set of nonlinear ordinary differential equations through a Galerkin approach. The resulting system of equations is solved...
Study of Aeroelastic Instability at a Panel Located in a Fully Filled Fuel Tank Wall
, M.Sc. Thesis Sharif University of Technology ; Dehghani Firouz-Abadi, Rouhollah (Supervisor)
Abstract
One of the classic problems in the aeroelasticity field is panel Fluttr that occurs in supersonic flow. Panels as wing skins, fuselage missile, and so are prone to this phenomenon, which causes fatigue and structures, will be demolished.In many cases, the wall panels and a full tank of fuel, this in this case, the vibration of the fluid-filled panels will be affected. There is clearly fluid into a tank filled with considering the approximation of incompressible fluid dynamics and vibration modes of the panel will change. In this study, a three-dimensional rectangular tank is considered the high walls on the elastic and supersonic flow passes.Fuel density and structural dimensions of Full...
Aeroelastic Analysis of Vehicle Under the Effect of Liquid Sloshing in Fuel Tank with Reduced Order Model
,
Ph.D. Dissertation
Sharif University of Technology
;
Haddadpour, Hassan
(Supervisor)
Abstract
The present thesis aims at investigating the dynamic interaction of slosh and aeroelasticity in the fuel contained aero vehicles. The main approach in this research is to develop reduced order models for description of the coupled system. In this regard, boundary element method is used to develop slosh dynamic model. Axisymmetric boundary element method with non-symmetric boundary conditions is used to develop slosh dynamic model for axisymmetric containers. Zoning method is used to develop slosh dynamic model for the multi-baffled tanks and based on it, slosh equivalent mechanical model is developed for multi-baffled tanks. Finite element method along with modal technique is used to develop...
Panel Flutter Analysis of Cylindrical Constrained Layer Damping (CLD) Panels
, M.Sc. Thesis Sharif University of Technology ; Haddadpour, Hassan (Supervisor)
Abstract
The purpose of this study is to analytically study the aeroelastic characteristics of the cylindrical shells fully treated with passive constrained layer damping (PCLD) to indicate the effects of various parameters on the behavior of such structures. Constraining the viscoelastic layers increases the amount of dissipated energy and the bending stiffness of the structure without considerable change of the weight.
A thin shell theory in conjunction with the Donell assumptions is employed for the shell and the constraining layer (CL) and the first order shear deformation theory (FSDT) is used for the viscoelastic layer to construct the model. The effects of rotary inertia and shear...
A thin shell theory in conjunction with the Donell assumptions is employed for the shell and the constraining layer (CL) and the first order shear deformation theory (FSDT) is used for the viscoelastic layer to construct the model. The effects of rotary inertia and shear...
Flutter of Constrained Layer Damping Cylindrical Shell with Fractional Derivative Viscoelastic Core
, M.Sc. Thesis Sharif University of Technology ; Hadadpour, Hassan (Supervisor) ; Dehghani Firouzabadi, Rohollah (Co-Advisor)
Abstract
This study presents the aeroelastic stability and vibration analysis of a sandwich circular cylindrical shells with a constrained viscoelastic layer. Based on the Donnell-Moshtari theory, the structural formulation of the cylinder is obtained using Lagrange method. The Rayleigh-Ritz method is implemented to solve the discretized governing equations. To describe the mechanical properties of the viscoelastic layer, the fractional order standard solid model is applied. The effects of variation of the governing parameters such as the length to radius ratio, radius to total thickness ratio and ratio of core to facing thickness on the stability margins and frequencies of sandwich cylindrical...
Numerical Simulation of 2D Panel Flutter in Compressible Flow using Compact Finite-Difference Method
, M.Sc. Thesis Sharif University of Technology ; Hejranfar, Kazem (Supervisor)
Abstract
In the present study, the numerical simulation of the panel flutter in compressible inviscid flow is performed by the compact finite difference method. For this purpose, the 2D compressible Euler equations written in the arbitrary Lagrange-Eulerian form are considered and the resulting system of equations in the generalized curvilinear coordinates is solved by the fourth-order compact finite-difference method. An appropriate nonlinear filter is applied for the shock capturing and for the solution to be stable. The governing equation for the panel is also numerically solved by using the fourth-order compact finite difference method. The time integration in the flow domain is made by the...
Parameter study of nonlinear aero-thermoelastic behavior of functionally graded plates
, Article International Journal of Structural Stability and Dynamics ; Volume 9, Issue 2 , 2009 , Pages 285-305 ; 02194554 (ISSN) ; Haddadpour, H ; Sharif University of Technology
2009
Abstract
In this paper, the effects of different parameters on the nonlinear aeroelastic behavior of functionally graded flat plates are investigated. Considering the through-the-thickness continuous variation of the material properties, a combination of the simple rule of mixtures and the Mori-Tanaka scheme is used for estimating the effective properties at each point. The von-Karman large strains and the piston theory are used to model the structural nonlinearity and aerodynamic loading, respectively. By Hamilton's principle the governing nonlinear partial differential equations of motion are derived and then converted to a set of nonlinear ordinary differential equations using the Galerkin method....
Aero-thermoelastic stability of functionally graded plates
, Article Composite Structures ; Volume 80, Issue 4 , 2007 , Pages 580-587 ; 02638223 (ISSN) ; Haddadpour, H ; Sharif University of Technology
2007
Abstract
In this paper, an analytical investigation intended to determine the aero-thermoelastic stability margins of functionally graded panels is carried out. For this purpose, piston theory aerodynamics has been employed to model quasi-steady aerodynamic loading. The material properties of the plate are assumed to be graded continuously across the panel thickness. A simple power-law and the Mori-Tanaka scheme are used for estimating the effective material properties such as temperature-dependent thermoelastic properties. The effects of compressive in-plane loads and both uniform and through the thickness non-linear temperature distributions are also considered. Hamilton's principle is used to...
Nonlinear oscillations of a fluttering functionally graded plate
, Article Composite Structures ; Volume 79, Issue 2 , 2007 , Pages 242-250 ; 02638223 (ISSN) ; Navazi, H. M ; Shadmehri, F ; Sharif University of Technology
2007
Abstract
In this paper, the nonlinear aeroelastic behavior of functionally graded plates is studied in supersonic flow. For this purpose, the von Karman strains and piston theory have been employed to model structural nonlinearity and quasi-steady aerodynamic panel loading, respectively. The material properties of the plate are assumed to be graded continuously in the direction of thickness. The variation of the properties follows a simple power-law distribution in terms of the volume fractions of constituents. The Hamilton's principle is used to construct the coupled nonlinear partial differential equations of motion. The derived equations are transformed into a set of coupled ordinary differential...
Panel flutter analysis of general laminated composite plates
, Article Composite Structures ; Volume 92, Issue 12 , November , 2010 , Pages 2906-2915 ; 02638223 (ISSN) ; Rasekh, M ; Haddadpour, H ; Sharif University of Technology
2010
Abstract
The problem of nonlinear aeroelasticity of a general laminated composite plate in supersonic air flow is examined. The classical plate theory along with the von-Karman nonlinear strains is used for structural modeling, and linear piston theory is used for aerodynamic modeling. The coupled partial differential equations of motion are derived by use of Hamilton's principle and Galerkin's method is used to reduce the governing equations to a system of nonlinear ordinary differential equations in time, which are then solved by a direct numerical integration method. Effects of in-plane force, static pressure differential, fiber orientation and aerodynamic damping on the nonlinear aeroelastic...
Flutter of functionally graded open conical shell panels subjected to supersonic air flow
, Article Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering ; Volume 227, Issue 6 , 2013 , Pages 1036-1052 ; 09544100 (ISSN) ; Shokrollahi, H ; Sharif University of Technology
2013
Abstract
In this article, analysis of supersonic flutter of functionally graded open conical shell panels with clamped and simply supported edges is presented. The aeroelastic stability problem is formulated based on first-order shear deformation theory as well as classical shell theory and solved using Galerkin method. The effects of the volume fractions of constituent materials, the semi-vertex and subtended angles, thickness, and length on the flutter of the functionally graded conical shell panel are investigated. It is shown that the discrepancies between the results of the present classical shell theory and first-order shear deformation theory for the critical aerodynamic pressure are generally...
Supersonic flutter prediction of functionally graded conical shells
, Article Composite Structures ; Volume 92, Issue 2 , 2010 , Pages 377-386 ; 02638223 (ISSN) ; Haddadpour, H ; Navazi, H.M ; Sharif University of Technology
2010
Abstract
Aero-thermoelastic analysis of a simply supported functionally graded truncated conical shell subjected to supersonic air flow is performed to predict the flutter boundaries. The temperature-dependent properties of the FG shell are assumed to be graded through the thickness according to a simple rule of mixture and power-law function of volume fractions of material constituents. Through the thickness steady-state heat conduction is considered for thermal analysis. To perform the stability analysis, the general nonlinear equations of motion are first derived using the classical Love's shell theory and the von Karman-Donnell-type of kinematic nonlinearity together with the linearized...