Optimal Design of Laminated-Composite Circular-Cylindrical Shells Subjected to Combined Loads

1988 ◽  
Vol 55 (1) ◽  
pp. 136-142 ◽  
Author(s):  
G. Sun ◽  
J. S. Hansen
Keyword(s):  
Circular Cylindrical Shell ◽  
Laminated Composite ◽  
Optimization Procedure ◽  
External Pressure ◽  
Buckling Load ◽  
Perturbation Approach ◽  
Combined Loads ◽  
Fixed Weight ◽  
Shell Analysis ◽  
Post Buckling

Optimization of the buckling load of a laminated-composite, circular-cylindrical shell subjected to axial compression, external pressure, torsion, or a combination thereof is undertaken. In the optimization procedure it is assumed that the shell has a fixed weight (length, radius and thickness); the buckling load is taken as the objective function which is maximized by adopting the lamina fiber orientations as the optimizing parameters. For the shell analysis a perturbation approach is used and the boundary conditions and nonlinear prebuckling effects are included; the analysis yields both the buckling load and the post-buckling character of the shell. The procedure developed is demonstrated for eight loading configurations. In addition, selected laminates were chosen for an experimental programme involving a series of graphite/epoxy shells. The predicted analytical and the measured experimental buckling loads are in very good agreement.

scholarly journals Optimization of Laminated Composite Plates for Maximum Biaxial Buckling Load

2020 ◽  
Vol 36 (2) ◽  
Author(s):  
Pham Dinh Nguyen ◽  
Quang-Viet Vu ◽  
George Papazafeiropoulos ◽  
Hoang Thi Thiem ◽  
Pham Minh Vuong ◽  
...  
Keyword(s):  
Fiber Orientation ◽  
Orientation Angle ◽  
Laminated Composite ◽  
Optimization Procedure ◽  
Composite Plates ◽  
Buckling Load ◽  
Biaxial Compression ◽  
Laminated Composite Plates ◽  
Design Variables ◽  
Fiber Orientation Angle

This paper proposes an optimization procedure for maximization of the biaxial buckling load of laminated composite plates using the gradient-based interior-point optimization algorithm. The fiber orientation angle and the thickness of each lamina are considered as continuous design variables of the problem. The effect of the number of layers, fiber orientation angles, thickness and length to thickness ratios on the buckling load of the laminated composite plates under biaxial compression is investigated. The effectiveness of the optimization procedure in this study is compared with previous works.

scholarly journals Post-Buckling Behaviour of laminated Cylindrical Panels with/without Cut-Outs

2019 ◽  
Vol 8 (3) ◽  
pp. 8026-8030
Keyword(s):  
Compressive Load ◽  
Laminated Composite ◽  
Cylindrical Panel ◽  
Buckling Load ◽  
Equilibrium Path ◽  
Cylindrical Panels ◽  
Post Buckling ◽  
The Impact ◽  
Generalized Finite Element ◽  
Composite Cylindrical Panel

Buckling and post-buckling analysis of isotropic and laminated composite cylindrical plates/panels under compressive load has been done by equilibrium path approach (arc-length technique). The impact of cut outs on buckling and post-buckling load of an isotropic and laminated composite cylindrical plates/panels has been assessed by utilizing summed up generalized finite element programming ANSYS. In post-buckling Eigen mode imperfection shape is picked for creating geometric undulations on cylindrical panels with/without circular cut-outs. The impact of the area and size of the cut out and furthermore the composite utilize point on the buckling load of laminated composite cylindrical panel is explored with simply supported boundary conditions. The post-buckling consequences of laminated cylindrical panels have been validated with existing appropriate writing (18) and are additionally stretched out for analysis of sheets/plates with cutouts. It has been seen that the as the curvature of the panel increases load bearing capacity is increasing irrespective of the material and with/without cut out.

Buckling Behavior of Optimal Laminated Composite Cylindrical Shells Subjected to Axial Compression and External Pressure

2011 ◽  
Vol 121-126 ◽  
pp. 48-54 ◽  
Author(s):  
Behzad Abdi ◽  
Hamid Mozafari ◽  
Ayob Amran ◽  
Roya Kohandel ◽  
Ali Alibeigloo
Keyword(s):  
Axial Compression ◽  
Optimization Design ◽  
Cylindrical Shells ◽  
Laminated Composite ◽  
Optimization Procedure ◽  
Imperialist Competitive Algorithm ◽  
External Pressure ◽  
Design Variables ◽  
Buckling Behavior ◽  
Composite Cylindrical Shells

In this study, the buckling behavior of optimum laminated composite cylindrical shells subjected to axial compression and external pressure are studied. The cylindrical shells are composed of multi orthotropic layers that the principal axis gets along with the shell axis (x). The number of layers and the fiber orientation of layers are selected as optimization design variables with the aim to find the optimal laminated composite cylindrical shells. The optimization procedure was formulated with the objective of finding the highest buckling pressure. The Genetic Algorithm (GA) and Imperialist Competitive Algorithm (ICA) are two optimization algorithms that are used in this optimization procedure and the results were compared. Also, the effect of materials properties on buckling behavior was analyzed and studied.

Dynamic Stability of an Isotropic Metal Foam Cylindrical Shell Subjected to External Pressure and Axial Compression

2011 ◽  
Vol 78 (4) ◽  
Author(s):  
Tomasz Belica ◽  
Marek Malinowski ◽  
Krzysztof Magnucki
Keyword(s):  
Cylindrical Shell ◽  
Dynamic Stability ◽  
Metal Foam ◽  
Circular Cylindrical Shell ◽  
Equations Of Motion ◽  
Element Model ◽  
External Pressure ◽  
Combined Loads ◽  
Nonlinear Approach ◽  
Isotropic Metal

This paper presents a nonlinear approach with regard to the dynamic stability of an isotropic metal foam circular cylindrical shell subjected to combined loads. The mechanical properties of metal foam vary in the thickness direction. Combinations of external pressure and axial load are taken into account. A nonlinear hypothesis of deformation of a plane cross section is formulated. The system of partial differential equations of motion for a shell is derived on the basis of Hamilton’s principle. The system of equations is analytically solved by Galerkin’s method. Numerical investigations of dynamic stability for the family of cylindrical shells with regard to analytical solution are carried out. Moreover, finite element model analysis is presented, and the results of the numerical calculations are shown in figures.

scholarly journals Experimental and Numerical Buckling Analyses of Laminated Composite Plates under Temperature Effects

2010 ◽  
Vol 19 (4) ◽  
pp. 096369351001900 ◽  
Author(s):  
Emin Ergun
Keyword(s):  
Composite Plate ◽  
Numerical Solutions ◽  
Laminated Composite ◽  
Composite Plates ◽  
Buckling Load ◽  
Fibre Reinforcement ◽  
Stacking Sequence ◽  
Laminated Composite Plates ◽  
Different Temperatures ◽  
Good Agreement

The aim of this study is to investigate, experimentally and numerically, the change of critical buckling load in composite plates with different ply numbers, orientation angles, stacking sequences and boundary conditions as a function of temperature. Buckling specimens have been removed from the composite plate with glass-fibre reinforcement at [0°]i and [45°]i (i= number of ply). First, the mechanical properties of the composite material were determined at different temperatures, and after that, buckling experiments were done for those temperatures. Then, numerical solutions were obtained by modelling the specimens used in the experiment in the Ansys10 finite elements package software. The experimental and numerical results are in very good agreement with each other. It was found that the values of the buckling load at [0°] on the composite plates are higher than those of other angles. Besides, symmetrical and anti-symmetrical conditions were examined to see the effect of the stacking sequence on buckling and only numerical solutions were obtained. It is seen that the buckling load reaches the highest value when it is symmetrical in the cross-ply stacking sequence and it is anti-symmetrical in the angle-ply stacking sequence.

scholarly journals Parametric Optimization of Isotropic and Composite Axially Symmetric Shells Subjected to External Pressure and Twisting

2021 ◽  
Vol 5 (5) ◽  
pp. 128
Author(s):  
Marek Barski ◽  
Paweł J. Romanowicz ◽  
Małgorzata Chwał ◽  
Adam Stawiarski
Keyword(s):  
Isotropic Material ◽  
Orientation Angle ◽  
Optimization Procedure ◽  
Middle Surface ◽  
External Pressure ◽  
Optimal Structure ◽  
Constant Thickness ◽  
Geometrical Shape ◽  
Axially Symmetric ◽  
Fiber Orientation Angle

The present paper is devoted to the problem of the optimal design of thin-walled composite axially symmetric shells with respect to buckling resistance. The optimization problem is formulated with the following constraints: namely, all analyzed shells have identical capacity and volume of material. The optimization procedure consists of four steps. In the first step, the initial calculations are made for cylindrical shells with non-optimal orientation of layers and these results are used as the reference for optimization. Next, the optimal orientations of layers for cylindrical shapes are determined. In the third step, the optimal geometrical shape of a middle surface with a constant thickness is determined for isotropic material. Finally, for the assumed shape of the middle surface, the optimal fiber orientation angle θ of the composite shell is appointed. Such studies were carried for three cases: pure external pressure, pure twisting, and combined external pressure with twisting. In the case of shells made of isotropic material the obtained results are compared with the optimal structure of uniform stability, where the analytical Shirshov’s local stability condition is utilized. In the case of structures made of composite materials, the computations are carried out for two different materials, where the ratio of E1/E2 is equal to 17.573 and 3.415. The obtained benefit from optimization, measured as the ratio of critical load multiplier computed for reference shell and optimal structure, is significant. Finally, the optimal geometrical shapes and orientations of the layers for the assumed loadings is proposed.

Thermal post-buckling of laminated and isotropic rectangular plates with fixed edges: Comparison of experimental and numerical results

2012 ◽  
Vol 226 (10) ◽  
pp. 2393-2401 ◽  
Author(s):  
Marco Amabili ◽  
Mohammad Reza Sareban Tajahmadi
Keyword(s):  
Deformation Theory ◽  
Laboratory Experiments ◽  
Continuation Method ◽  
Shear Deformation Theory ◽  
Laminated Composite ◽  
Numerical Results ◽  
Rectangular Plates ◽  
Arc Length ◽  
Thermal Changes ◽  
Post Buckling

Post-buckling behaviors of laminated composite and isotropic rectangular plates subjected to various thermal changes are studied. Geometric imperfections are taken into account since they play a fundamental role. The plate is modeled using a nonlinear, higher order shear deformation theory. Plates with clamped edges are considered. A pseudo-arc length continuation method is used to obtain numerical results. Laboratory experiments have been performed in order to compare to the numerical calculations.

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