Analysis of Tubular Composite Cylindrical Shells (original) (raw)
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Composite cylindrical shells under combined loading
MATEC Web of Conferences, 2018
The structural design of a cylindrical shell made of a unidirectional glass/epoxy fiber composite and subjected to torsional moment and internal pressure is studied. An anisotropic model for analysis of composite material is applied. The minimum wall thickness of the shell, with the use of the Tsai-Hill failure criterion, is derived. In this connection, the strain energy density criterion (SED) is applied, by which the critical crack length is determined. In this paper, we illustrate the fracture methodology towards the design of a cylindrical shell structure for determining safe operation. Finite element analysis and analytical method were also established.
The Laminated cylindrical shells are being used in submarine, underground mines, aerospace applications and other civil engineering applications. Thin cylindrical shells and panels are more prone to fail in buckling rather than material failure. In this present study linear and non-linear buckling analysis of GFRP cylindrical shells under axial compression is carried out using general purpose finite element program (ANSYS). Non-linear buckling analysis involves the determination of the equilibrium path (or load-deflection curve) upto the limit point load by using the Newton-Raphson approach. Limit point loads evaluated for geometric imperfection magnitudes shows an excellent agreement with experimental reults [25]. The influence of composite cylindrical shell thickness, radius variation on buckling load and buckling mode has also investigated. Present study finds direct application to investigate the effect of geometric imperfections on other advanced grid-stiffened structures .
Materials
This paper analyses the issues relative to the modelling of tubular (cylindrical) composite structures. This paper aims to describe the design of a multi-layer structure of filament-wound composite pipes where, after loading, the hoop-stress distribution would be as uniform as possible. That would allow the mass of the composite to decrease while maintaining the proper mechanical strength. This publication presents the development of a calculation model dedicated to mono- and multi-layered tubular composite structures. The equations describing the stress pattern were based on the Lamé Problem, whereas to describe the modelled structures, an anisotropy coefficient was introduced and interlayer pressures values were determined. To verify the calculations, experimental studies were performed. The test specimens were fabricated by winding fibre bundles around a steel core (as rings with an internal diameter of 113 mm and a height of 30 mm). For the test, the method of pressing a conical...
International Journal of Engineering Research and Technology (IJERT), 2013
https://www.ijert.org/buckling-analysis-of-laminated-composite-cylindrical-shells-subjected-to-axial-compressive-loads-using-finite-element-method https://www.ijert.org/research/buckling-analysis-of-laminated-composite-cylindrical-shells-subjected-to-axial-compressive-loads-using-finite-element-method-IJERTV2IS1370.pdf The Laminated cylindrical shells are being used in submarine, underground mines, aerospace applications and other civil engineering applications. Thin cylindrical shells and panels are more prone to fail in buckling rather than material failure. In this present study linear and non-linear buckling analysis of GFRP cylindrical shells under axial compression is carried out using general purpose finite element program (ANSYS). Non-linear buckling analysis involves the determination of the equilibrium path (or load-deflection curve) upto the limit point load by using the Newton-Raphson approach. Limit point loads evaluated for geometric imperfection magnitudes shows an excellent agreement with experimental reults [25]. The influence of composite cylindrical shell thickness, radius variation on buckling load and buckling mode has also investigated. Present study finds direct application to investigate the effect of geometric imperfections on other advanced grid-stiffened structures .
In present work, post-buckling behavior of imperfect (of eigen form) laminated composite cylindrical shells with different L/D and R/t ratios subjected to axial, bending and torsion loads has been investigated by using an equilibrium path approach in the finite element analysis. The New-ton-Raphson approach as well as the arc-length approach is used to ensure the correctness of the equilibrium paths up to the limit point load. Post-buckling behavior of imperfect cylindrical shells with different L/D and R/t ratios of interest is obtained and the theoretical knock-down factors are reported for the considered cylindrical shells.
Estimation of interlaminar stresses in fibre reinforced composite cylindrical shells
Computers & Structures, 1991
Co finite element formulation for flexure-membrane coupling behavior of symmetric and asymmetric laminated cylindrical shells based on a higher-order displacement model is presented. This theory incorporates a realistic nonlinear variation of displacements through the shell thickness, and eliminates the use of shear correction coefficient/s. The discrete element chosen is a nine-noded quadrilateral with nine degrees of freedom per node. The solutions are obtained through two formulations: (1) the geometrically thin shell formulation, based on the assumption that the ratio of thickness to radius of the shell is very much less than unity, and (2) the geometrically thick shell formulation, in which (h/R)* 4 1. In these formulations, the in-plane stresses are obtained via constitutive relations. Reliable estimates of interlaminar stresses from equilibrium equations are obtained. A finite difference scheme maintaining the continuity of interlaminar stresses across the shell thickness is developed and used. The results obtained are compared with available elasticity, closed-form and other finite element solutions.
Buckling characteristic of multi-laminated composite elliptical cylindrical shells
International Journal of Advanced Structural Engineering (IJASE), 2014
Fiber-reinforced composite materials continue to experience increased adoption in aerospace, marine, automobile, and civil structures due to their high specific strength, high stiffness, and light weight. This increased use has been accompanied by applications involving nontraditional configurations such as compression members with elliptical cross-sections. To model such shapes, we develop and report an improved generalized shell element called 4EAS-FS through a combination of enhanced assumed strain and the substitute shear strain fields. A flat shell element has been developed by combining a membrane element with drilling degree-of-freedom and a plate bending element. We use the element developed to determine specifically buckling loads and mode shapes of composite laminates with elliptical cross-section including transverse shear deformations. The combined influence of shell geometry and elliptical cross-sectional parameters, fiber angle, and lay-up on the buckling loads of an elliptical cylinder is examined. It is hoped that the critical buckling loads and mode shapes presented here will serve as a benchmark for future investigations.
International Journal of Mechanical and Materials Engineering, 2015
Background: Advanced lightweight laminated composite shells are increasingly being used in modern aerospace structures to enhance their structural efficiency and performance. Such thin-walled structures are susceptible to buckling when subjected to static and dynamic compressive stresses. This paper reports on the numerical (finite element method (FEM)) study on buckling of carbon fibre-reinforced plastic (CFRP) layered composite cylinders under displacement and load-controlled static axial compression. Methods: The effects of geometric properties, lamina lay-up, amplitudes of imperfection and parametric research of the shape (square, circular) and the dimensions (axial and circumferential sizes, diameter) of the opening on the strength of the cylinders under compression were studied. The measurement of imperfections on the cylindrical surface is achieved using the interpolation method and Fourier series. Results: The analysis indicates that the critical load is sensitive to the circumferential size of the opening. The function (critical load-circumferential size of the opening) is linear for large openings and independent of the geometrical imperfections of the shell. However, for small openings, it is necessary to take into account the coupling between the initial geometrical imperfections and the openings. Conclusions: The linear approach does not fit due to the importance of the evolution of the displacements near the openings. Also, it was shown that the buckling behaviour of thin composite cylindrical shells can be evaluated accurately via modelling to determine the imperfections and the material properties in FEM.
An experiment study of fiberglass (E-400) composite tubes subjected to quasi-static compression loading is presented. The main objective of this study is to increase the understanding of the behavior of deformation and failure mode of composite tubes under axial loading. Three different types of shapes had been selected; which are circular, triangular and square. These composite tubes have been fabricated with 4, 6, 8 and 10 layers, using 0/90° fiber orientation angle. The tubes inner diameter is 100mm and the height is 100mm for all the specimens. The results had been observed including the experimental results of the load-displacement curves, the initial failure load, the maximum failure load and the average failure load. From these results, the crashworthiness parameters were calculated. It was found that the initial failure load and the total energy absorption are increasing when the number of layers increased for the specimen at the same condition.
Failure Analysis of a Composite Cylinder
Composite cylinders are high-strength containers made from a mixture of fibre glass or carbon fibers and a plastic resin typically epoxy. A lamina is assumed to be homogeneous and the mechanical behavior is characterized by a set of equivalent or effective moduli and strength properties. In the phenomenological approach, the lamina properties are determined experimentally by conducting tests on a single lamina or a laminate. Once the mechanical properties of the ply are known the initial failure of the ply within a laminate or structure can be predicted by applying an appropriate failure criterion. Failure types are dependent on loading, stacking sequence, and specimen geometry. There are many proposed theories to predict the one-set of failures. Most of failure criteria are based on the stress state in a lamina. The present work aims to determine the effect of diameter-to-thickness ratio 'S' with respect to failure pressure of a four layers, introduction of hoop layers at ends on four layered cylinder and introduction of hoop layers at middle of six layered angle-ply laminated cylinder which is analyzed by using Finite Element software ANSYS. The variation of failure pressure with respect to fiber angles was also presented in this work.