scholarly journals Multiobjective Mechanical Buckling Optimization of Variable Thickness FG Cylindrical Shell with Initial Imperfection

2019 ◽  
Vol 14 (2) ◽  
pp. 658-665
Author(s):  
M. Hayati ◽  
A.A. Atai
Keyword(s):  
Cylindrical Shell ◽  
Variable Thickness ◽  
Initial Imperfection ◽  
Buckling Optimization ◽  
Mechanical Buckling

Buckling Optimization of Variable Thickness Composite Plates Subjected to Nonuniform Loads

AIAA Journal ◽  
2004 ◽  
Vol 42 (2) ◽  
pp. 228-231 ◽  
Author(s):  
A. R. de Faria ◽  
S. F. M. de Almeida
Keyword(s):  
Variable Thickness ◽  
Composite Plates ◽  
Buckling Optimization

scholarly journals A Semi-Analytical Solution for Elastic Analysis of Rotating Thick Cylindrical Shells with Variable Thickness Using Disk Form Multilayers

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Mohammad Zamani Nejad ◽  
Mehdi Jabbari ◽  
Mehdi Ghannad
Keyword(s):  
Cylindrical Shell ◽  
Analytical Solution ◽  
Differential Equations ◽  
Variable Thickness ◽  
Deformation Theory ◽  
Shear Deformation Theory ◽  
First Order ◽  
Thick Cylinder ◽  
Good Agreement

Using disk form multilayers, a semi-analytical solution has been derived for determination of displacements and stresses in a rotating cylindrical shell with variable thickness under uniform pressure. The thick cylinder is divided into disk form layers form with their thickness corresponding to the thickness of the cylinder. Due to the existence of shear stress in the thick cylindrical shell with variable thickness, the equations governing disk layers are obtained based on first-order shear deformation theory (FSDT). These equations are in the form of a set of general differential equations. Given that the cylinder is divided intondisks,nsets of differential equations are obtained. The solution of this set of equations, applying the boundary conditions and continuity conditions between the layers, yields displacements and stresses. A numerical solution using finite element method (FEM) is also presented and good agreement was found.

scholarly journals Buckling of Imperfect, Axisymmetric, Homogeneous Shells of Variable Thickness: Perturbation Solution

2005 ◽  
Author(s):  
Dennis Williams
Keyword(s):  
Cylindrical Shell ◽  
Variable Thickness ◽  
Large Diameter ◽  
Compressive Load ◽  
Thin Wall ◽  
Shells Of Revolution ◽  
Equilibrium Equations ◽  
Asme Code ◽  
Current Design ◽  
Section Viii

This paper presents the first of a series of solutions to the buckling of imperfect cylindrical shells subjected to an axial compressive load. In particular, the initial problem reviewed is the case of a homogeneous cylindrical shell of variable thickness that is of an axisymmetric nature. The equilibrium equations as first introduced by Donnell over seventy years ago are thoroughly presented as a basis for embarking upon a solution that makes use of perturbation methods. The ultimate objective of these calculations is to achieve a quantitative assessment of the critical buckling load considering the small axisymmetric deviations from the nominal shell wall thickness. Clearly in practice, large diameter, thin wall shells of revolution that form stacks (as found in flue gas desulphurization absorber assemblies) are never fabricated with constant diameters and thicknesses over the entire length of the assembly. As such, ASME Boiler and Pressure Vessel Code Section VIII fabrication tolerances as supplemented by ASME Code Case 2286-1 are reviewed and addressed in light of the findings of the current study and resulting solutions with respect to the critical buckling loads. The method and results described herein are in stark contrast to the “knockdown factor” approach currently utilized in ASME Code Case 2286-1. Recommendations for further study of the imperfect cylindrical shell are also outlined in an effort to improve on the current design rules regarding column buckling of large diameter shells designed in accordance with ASME Section VIII, Divisions 1 and 2; and ASME STS-1 in combination with the suggestions contained within Code Case 2286-1.

Free vibration analysis of laminated composite conical, cylindrical shell and annular plate with variable thickness and general boundary conditions

2021 ◽  
Author(s):  
Kwang Hun Kim ◽  
Songhun Kwak ◽  
Kwangil An ◽  
Kyongjin Pang ◽  
Pyol Kim
Keyword(s):  
Cylindrical Shell ◽  
Free Vibration ◽  
Boundary Conditions ◽  
Variable Thickness ◽  
Conical Shell ◽  
Annular Plate ◽  
Laminated Composite ◽  
Haar Wavelet ◽  
Algebraic Equations ◽  
Arbitrary Boundary

Abstract This paper presents a unified solution method to investigate the free vibration behaviors of laminated composite conical shell, cylindrical shell and annular plate with variable thickness and arbitrary boundary conditions using the Haar wavelet discretization method (HWDM). Theoretical formulation is established based on the first order shear deformation theory(FSDT) and displacement components are extended Haar wavelet series in the axis direction and trigonometric series in the circumferential direction. The constants generating by the integrating process are disposed by boundary conditions, and thus the equations of motion of total system including the boundary condition are transformed into an algebraic equations. Then natural frequencies of the laminated composite structures are directly obtained by solving these algebraic equations. Stability and accuracy of the present method are verified through convergence and validation studies. Effects of some material properties and geometric parameters on the free vibration of laminated composite shells are discussed and some related mode shapes are given. Some new results for laminated composite conical shell, cylindrical shell and annular plate with variable thickness and arbitrary boundary conditions are presented, which may serve as benchmark solutions.

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