Postbuckling of composite cylinders under external hydrostatic pressure (original) (raw)
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This paper was aimed to investigate the post buckling behaviour of moderately thick-walled filament-wound carbonepoxy composite cylinders under external hydrostatic pressure through finite element analysis for under water vehicle applications.The winding angles were [±30/90] FW, [±45/90] FW and [±60/90] FW. Finite element software ANSYS 14.0 were used to predicted the buckling pressure of filament-wound composite cylinders.For the finite element modeling of the composite cylinder, an eight-node shell element is used.To verify the finite element results for comparison, three finite element software, MSC/NASTRAN , MSC/MARC and an in-house program ACOS were used.Among these software's, the finite element software ANSYS predicts the buckling loads within 1.5% deviation.
2015
Due to the necessity of access opening, inspection paths, installation, entrance and exit doors, etc, creation of cutouts on the vessel structure is unavoidable. On the other hand, composite structures and structural analysis are complex and creating cutout and imperfect structure increases this complexity. The aim of this research is to determine the mechanical response of three cutout positions on composite pressure vessels under 30 bar external pressure, so that no buckling and fracture failure occurs. Also, the optimum composite vessel thickness for this condition and cutout effect has been determined in this study. The studied vessels are made from E-Glass fiber and Epoxy matrix. Finite element simulation was used to investigate the parameters effect. For this reason, commercial ABAQUS software and linear and non-linear analysis was carried out to examine the parameters. To evaluate the simulation results, two composite vessels were manufactured and fractured under external pressure. Moreover, the final vessel with three cutouts was tested under 30 bar external pressure. The concluded results show that the optimum thickness was 16 mm for vessel with three cutouts and creating the cutouts led to decreased buckling pressure. Also, with increasing cutout size the percentage of buckling pressure increased.
Global Journal of Researches in Engineering:
In this present study the post buckling cha-racteristics of moderately thick-walled filament-wound carbon–epoxy composite cylinders under external hydrostatic pressure were investigated through finite element analysis for under water vehicle applications. The winding angles were [±30/90] FW, [±45/90] FW and [±60/90] FW. Finite element software ANSYS 14.0 were used to predicted the buckling pressure of filament-wound composite cylinders. For the finite element modeling of a composite cylinder, an eight-node shell element is used. To verify the finite element results for comparison, three finite element software, MSC/NASTRAN, MSC/MARC and an in-house program ACOS were used. Among these software’s, the finite element software ANSYS predicts the buckling loads within 1.5% deviation. The analysis and test results showed that the cylinders do not recover the initial buckling pressure after buckling and that this leads directly to the collapse. Major failure modes in the analysis were dominated by the helical winding angles. The finite element analysis shows global buckling modes with four waves in the hoop direction.
Materials Sciences and Applications, 2015
The aim of the research work was to numerically investigate the residual stresses induced between the layers of fiber metal laminate (FML) cylinder (glass/epoxy reinforced aluminum laminates) under buckling hydrostatic loading. For the analysis of buckling behavior of FML cylinders, various fiber orientations such as 0/90˚, 60/30˚, ±45˚ and ±55˚ and different FRP thickness of 1, 2, and 3 mm were considered. The aluminum cylinder of inner diameter 80 mm, length 800 mm and wall thickness 1 mm was modeled with SHELL281 element type and a total of 1033 elements were used for computing the induced residual stresses between the layers. The results show that magnitude of residual stresses between the layers decreased along the thickness from outer layer towards the inner layer in sine wave form. The maximum residual Von-Mises stress was at inner aluminum layer while the maximum residual radial stress was at the outermost layer of FML cylinder due to the inward pressure. Among all types of FML cylinder 0/90˚ fiber oriented FML cylinder exhibited the least radial stress and a maximum Von-Mises stress along the FRP thickness.
Ocean Engineering
This paper derives an empirical formula for predicting the collapse strength of composite cylindrical-shell structures under external hydrostatic pressure loads as a function of geometric dimensions and layered angles, where the effects of initial manufacturing imperfections are implicitly taken into account. A series of experiments are undertaken on [ /90]FW filament-wound-type composite cylindrical-shell models subjected to collapse pressure loads. A total of 20 composite cylindrical-shell models are tested to derive the empirical formula, which is validated by comparison with experimental data, existing design formulas of ASME 2007 and NASA SP-8700, and solutions of the nonlinear finite element method. It is concluded that the proposed formula accurately predicts the collapse pressure loads of filament-wound composite cylinders and will thus aid the safety design of composite cylindrical shell-structures under external pressure loads.
International Journal of Mechanical Sciences, 2008
A postbuckling analysis is presented for a three-dimensional (3D) braided composite cylindrical shell of finite length subjected to combined loading of external pressure and axial compression in thermal environments. Based on a micro-macro-mechanical model, a 3D braided composite may be a cell system and the geometry of each cell is highly dependent on its position in the cross-section of the cylindrical shell. The material properties of epoxy are expressed as a linear function of temperature. The governing equations are based on a higher order shear deformation shell theory with a von Ka´rma´n-Donnell-type kinematic nonlinearity and includes thermal effects. A singular perturbation technique is employed to determine interactive buckling loads and postbuckling equilibrium paths. The numerical illustrations concern the postbuckling behavior of perfect and imperfect, braided composite cylindrical shells with different values of shell geometric parameter and of fiber volume fraction under combined loading conditions. The results show that the shell has lower buckling loads and postbuckling paths when the temperature-dependent properties are taken into account. The effects of temperature rise, fiber volume fraction, shell geometric parameter, load-proportional parameter, as well as initial geometric imperfections are studied. r
IJERT-Buckling Analysis of Composite Cylinders Subjected to Axial Compressive Loads
International Journal of Engineering Research and Technology (IJERT), 2015
https://www.ijert.org/buckling-analysis-of-composite-cylinders-subjected-to-axial-compressive-loads https://www.ijert.org/research/buckling-analysis-of-composite-cylinders-subjected-to-axial-compressive-loads-IJERTV4IS040743.pdf Slender structures will buckle when subjected to pressure or compressive loads. Buckling is also important factor to decide the failure of the structure. Generally columns and higher length cylinders will buckle and they will be manufactured by the metals. In the present work slender cylinder subjected to axial compressive load manufactured by different composite materials is analyzed. The effect of cylinder length to thickness ratio, materials and stacking angle are analyzed. It results that as the cylinder length to thickness ratio is increasing, the buckling load is decreasing and carbon epoxy woven fabric with stacking angle of 90 o shows higher buckling load.
Thin-Walled Structures, 1993
A new approach is extended to investigate the buckling and postbuckling behaviour of perfect and imperfect, stringer and ring stiffened cylindrical shells of finite length subject to combined loading of external pressure and axial compression. The formulations are based on a boundary layer theory which includes the edge effect in the postbuckling analysis of a thin shell. The analysis uses a singular perturbation technique to determine the buckling loads and the postbuckling equilibrium paths. Some interaction curves for perfect and imperfect stiffened cylindrical shells are given and compared well with experimental data. The effects of initial imperfection on the interactive buckling load and postbuckling behaviour of stiffened cylindrical shells have also been discussed.
Numerical Investigation Of Stiffened Composite Cylindrical Shell Subjected To External Pressure
2013
Abstract— The present study is devoted for the development of a mathematical model to predict the structural behavior and critical pressure of composite cylindrical shell under external pressure using finite element analysis. The composites can be tailored to match the external loading. The effect of fibre orientation angle along with stacking sequence of the composites on the loading carrying capacity of the structure is assessed. A quantitative assessment of the effects of discrete stiffeners on the local and global behaviour of shells stiffened by rings is carried out for understanding the response of structure. The study captures the local effects of the stiffener spacing and highlights the effect of eccentricity of stiffeners on the strength of shells. The response of the composite shells has been investigated for different values of the shell thickness.