# Free vibration analysis of anisotropic laminated composite shells of revolution

2005
Yavuzbalkan, Erdem
In this thesis, the free vibration analysis of anisotropic laminated composite shells of revolution (ALCSOR) is studied. The governing equations are kinematic, constitutive, and motion equations. Geometrically linear strain-displacement equations of Reissner-Naghdi shell theory in combination with first-order shear deformation theory in which transverse shear and rotatory inertia effects are taken into consideration. The constitutive relations are for macrosopically ALCSOR in which statically equivalent force and moment resultants, instead of internal stresses for a single layer, are introduced. Equations of motion for the free vibration problem are obtained by the Hamilton̕s principle. The derived governing equations for the free vibration analysis of ALCSOR are initially formulated into a system of partial differential equations in terms of fundamental variables. Then, those partial differential equations are reduced to a system of first order ordinary differential equations by applying finite exponential Fourier Transform method resulting in a two point boundary value problem. It has been demonstrated that the application of the finite exponential Fourier transform made it possible to solve the governing equations, comprising the full anisotropic form of the constitutive equations, which was otherwise impossible to solve with the classical Fourier decomposition method. First, the boundary value problem formulated is reduced to a series of initial value problems, then the multisegment numerical integration is used in combination with the frequency trial method in order to find the critical modes within a given range of natural frequencies. A computer code DALSOR is written for the solution of the natural frequencies and mode shapes of mascroscopically ALCSOR. DALSOR is applicable to any general boundary condition at both ends of the shell, and allows for variation

# Suggestions

 Stress analysis of symmetric aluminum composite-laminated beams under a bending moment: Materially nonlinear only Sayman, O; Belevi, M; Altinhan, M (SAGE Publications, 2005-01-01) In this study, an elastic-plastic stress analysis is carried out on symmetric laminated composite beams subjected to a bending moment. The composite beam is to be strain hardening. The Bernoulli and Euler hypotheses are assumed to be valid. The Tsai-Hill theory is used as a yield criterion in the solution. The solution is carried out for (90 degrees/0 degrees)(2), (30 degrees/-30 degrees)(2), (45 degrees/-45 degrees)(2), and (60 degrees/-60 degrees)(2) orientations. The bending moment is to be found the hig...
 TORSIONAL VIBRATIONS OF LAYERED COMPOSITE PARABOLOIDAL SHELLS Kayran, Altan (Elsevier BV, 1990-09-08) An analysis is presented for the torsional vibration characteristics of layered composite paraboloidal shells. The conditions for the uncoupling of the torsional modes from the bending and extensional modes are first determined for a layered shell of revolution. A finite difference scheme is developed for the solution of the resulting governing equation for the uncoupled torsional frequencies. The results of the finite difference solution for the paraboloids are compared with the analytical solution of unco...
 On the nonlinear buckling analysis of composite shells and the associated numerical difficulties Akkas, N; Toroslu, R (1998-08-21) The purpose of this work is to study nonlinear, snap-through buckling behavior of shallow shells which are made of isotropic and laminated composite materials under general static loading using numerical techniques. In addition to the finite difference computer programs which we developed for this special purpose, the general pur-pose computer program ANSYS has also been used. The special purpose programs that we have developed make use of the governing equations, which are in terms of the displacement comp...
 Mechanical behaviour of Al2O3-ZrO2 minicomposite reinforced glass matrix optomechanical composite Dericioğlu, Arcan Fehmi (Informa UK Limited, 2003-08-01) To understand the effect of a 'mesh-structured reinforcement' on the optical and mechanical properties of optomechanical composites, a unidirectional Al2O3 fibre-ZrO2 matrix minicomposite reinforced glass matrix optomechanical composite has been fabricated. By regular alignment of the minicomposites in the glass matrix as part of the 'mesh structure' a high degree of optical transparency is obtained in the composite; this transparency is proportional to its 'optical window' regions. The mesh structured rein...
 Single- and double-helix vortex breakdown as two dominant global modes in turbulent swirling jet flow Vanierschot, Maarten; Mueller, Jens S.; Sieber, Moritz; Perçin, Mustafa; van Oudheusden, Bas W.; Oberleithner, Kilian (Cambridge University Press (CUP), 2020-01-25) In this paper, we study the shape and dynamics of helical coherent structures found in the flow field of an annular swirling jet undergoing vortex breakdown. The flow field is studied by means of time-resolved tomographic particle image velocimetry measurements. The obtained flow fields are analysed using both classic and spectral proper orthogonal decomposition. Despite the simple geometrical set-up of the annular jet, the flow field is very complex. Two distinct large-scale helical flow structures are ide...
Citation Formats
E. Yavuzbalkan, “Free vibration analysis of anisotropic laminated composite shells of revolution,” M.S. - Master of Science, Middle East Technical University, 2005. 