Buckling of functionally graded carbon nanotubes reinforced composite joined spherical-cylindrical-spherical thin-walled structure

Nanocomposite and sandwich plates with a honeycomb core are characterized by a high strength-to-mass ratio. Thus, such a solution is very promising for the aerospace and aircraft industry. This paper represents a mathematical model for a nanocomposite functionally gradient cylindrical shell interacting with a supersonic gas flow. To obtain such a model, the predetermined form method is used. An ordinary nonlinear differential equations system is obtained to describe the self-sustained vibrations of the shell. The structure model is developed using nonlinear strain-displacement relationships to analyze self-sustained vibrations. A model describing self-sustained vibrations of a sandwich conical shell interacting with a supersonic gas flow is obtained. The core layer of the shell is an FDM-manufactured honeycomb. The stress state of the structure is analyzed using the highorder shear deformations theory. Each layer’s stress state is described by five coordinates which are the three displacements of the midsurface and two angles of rotation of the normal to the midsurface. At the layers’ junctions, the border conditions of displacements’ continuity are used. To analyze self-sustained vibrations, the nonlinear strain-displacement relationships are utilized. Using the normal modes technique allows us to obtain a nonlinear autonomous dynamic system. Results of numerical simulations of self-sustained vibrations are provided. They are obtained by solving a nonlinear boundary value problem for the ordinary differential equations system using shooting and continuation techniques. Experimental investigation of sandwich plates’ fatigue with honeycomb core is considered. A method of fatigue testing of sandwich plates is described. The testing results are presented using S-N diagrams.

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Section: моделі тонкостінних нанокомпозитних конструкційunclassified

Dynamic Properties of Nanocomposite and Three-Layer Thin-Walled Aerospace Elements Manufactured by Additive Technologies

Avramov¹,

Uspensky²,

Derevyanko³

et al. 2023

Kosm. nauka tehnol.

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“…For example, the application of GNPs in control of the dynamic response of the conical shells was investigated in Al-Furjan et al 4 and Keshtegar et al 5 In some other studies, CNTs are employed as the reinforcing phase of the composites. In several studies such as Mohammadimehr et al, 6 Adhikari and Singh, 7 and Avramov et al 8 it has been showed that enrichment of the structures by CNTs leads to enhance of their structural characteristics. In this regard, Shahmohammadi et al 9 developed an analytical solution based on the modified interaction method to investigate the snap-through behavior of CNT-reinforced shallow spherical shells.…”

Section: Introductionmentioning

confidence: 99%

An analytical closed-form solution for free vibration and stability analysis of curved sandwich panels made of porous metal-foam core and nanocomposite reinforced face-sheets

Badarloo,

Salehipour

2023

Proceedings of the Institution of Mechanical Engineers, Part C:

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This paper aims to obtain an analytical solution for free vibration and stability analysis of shallow curved sandwich panels made of a porous metal-foam core and nanocomposites reinforced sheets resting on a Winkler-Pasternak elastic foundation. In this regard, two nanocomposites, carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs) are considered for reinforcing the face-sheets. The governing equations are developed by considering the transversal shear strains based on the first-order shear deformation theory (FSDT). The obtained system of differential equations representing the dynamic equilibrium and compatibility of the proposed curved sandwich panels are solved analytically, using the principal of Galerkin method. In order to examine the results of developed formulation, some benchmark examples are adopted from the existing literature and the obtained results corresponding to the considered examples are compared with those are presented in the references. Using the achieved numerical results in the framework of a comprehensive parametric study, the effects of various material and geometrical factors and also various boundary conditions on the natural frequencies and buckling loads of the proposed sandwich panels are assessed. By performing the extensive parametric study it was observed that several results corresponding to the free vibration and stability of the proposed sandwich panels can be achieved by the present method without spending much time for computations. On the contrary, in order to achieve the similar results using the numerical methods, a time-consuming process is required which can justify the novelty of the present work.

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Dynamic instability in the interaction of a composite shell made by additive technologies with a gas flow

Uspenskyi,

Avramov,

Salenko

et al. 2024

Teh. Meh.

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The dynamic instability of a composite cylindrical-conical thin-walled structure interacting with a supersonic gas flow is analyzed. This structure consists of three layers. The middle layer is manufactured by FDM additive technologies from ULTEM material. The top and bottom layers are manufactured from carbon-filled plastic. Free linear vibrations of the thin-walled structure are studied by Rayleigh?Ritz semi-analytical method to obtain a model of dynamic instability. The free linear vibrations are analyzed numerically. The obtained eigenfrequencies and eigenmodes are in close agreement with the data obtained by the ANSYS commercial software. The calculated eigenmodes were used to construct a model of composite cylindrical-conical shell instability. This model of instability is a system of ordinary linear differential equations in the generalized coordinates of the thin-walled structure. The supersonic gas flow is described by a piston theory, which accounts for the angle of attack. The study of the dynamic instability of the composite cylindrical-conical shell reduces to analyzing the trivial equilibrium instability of the system of ordinary differential equations. Characteristic exponents are calculated to analyze the stability of the trivial solution. These characteristic exponents are calculated from an eigenvalue problem. If the angle of attack is 12° and the Mach number is small, the minimal value of the critical pressure is observed for three circular waves. If the Mach number is increased, the minimal critical pressure is observed for four and five circular waves. If the angle of attack is 6° and the Mach number is small, the minimal critical pressure is observed for two circular waves. If the Mach number is increased, the minimal critical pressure is observed for three and four circular waves. The dynamic stability is lost for eigenmodes with a small number of circular waves

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Buckling of functionally graded carbon nanotubes reinforced composite joined spherical-cylindrical-spherical thin-walled structure

Cited by 3 publications

References 52 publications

Dynamic Properties of Nanocomposite and Three-Layer Thin-Walled Aerospace Elements Manufactured by Additive Technologies

Dynamic Properties of Nanocomposite and Three-Layer Thin-Walled Aerospace Elements Manufactured by Additive Technologies

An analytical closed-form solution for free vibration and stability analysis of curved sandwich panels made of porous metal-foam core and nanocomposite reinforced face-sheets

Dynamic instability in the interaction of a composite shell made by additive technologies with a gas flow

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