NASA TN D-5050 MECHANICAL BEHAVIOR OF BORON-EPOXY AND GLASS-EPOXY FILAMENT-WOUND CYLINDERS UNDER VARIOUS LOADS (original) (raw)
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Composites Science and Technology, 2008
The influence of winding pattern on the mechanical response of filament wound glass/epoxy cylinders exposed to external pressure is studied by testing cylindrical specimens having stacked layers with coincident patterns in a hyperbaric testing chamber. Different analytical models are evaluated to predict buckling pressure and modes of thin wall cylinders (diameter to thickness ratio d/h of 25) and satisfactory predictions are obtained which are in the same order of magnitude that those obtained in experimental results. Test results show no evident pattern influence on either strength (implosion pressure) or buckling behavior (buckling modes) of thin wall or thick wall (d/h of 10) cylinders.
Journal of Reinforced Plastics and Composites-2005-Akcay-1169-79
In this investigation, a failure analysis is performed on analytical expressions of multilayered filament wound structures (FWS) in composite cylinders for the plane-strain and closed-end condition cases, under internal pressure and uniform thermal loading. The multilayer filament wound composite pressure closed-end cylinders are oriented symmetrically and antisymmetrically. The mechanical properties of composite cylinders are investigated considering a glass-epoxy multilayered composite cylinder. The failure analysis is carried out on different orientations of the multilayered composite cylinders. The failure pressure is found to be high at increased temperatures for the plane-strain cases. It is nearly the same for the closed-end case.
Design, modeling, optimization, manufacturing and testing of variable-angle filament-wound cylinders
Composites Part B: Engineering, 2021
This work demonstrates the potential of manufacturing variable-angle composite cylinders via filament winding (FW), called VAFW. The proposed design strategy allows different filament angles along the axial direction by dividing the cylinder into regions of constant angle called frames. Designs using two, four, or eight frames are herein investigated. A genetic algorithm is applied to optimize each design for maximum axial buckling load. A design with minimum manufacturable filament angle is included in the study. All structures are manufactured and tested under axial compression, with displacements and strains measured by digital image correlation (DIC). The thickness and mid-surface imperfections of the different designs are measured through DIC and used to explain the observed buckling mechanisms. These imperfections are incorporated into a nonlinear numerical model along with a progressive damage analysis. Additionally, a scaling factor is applied on the measured imperfections to enable an imperfection sensitivity study on the proposed designs. The VAFW design shows buckling strength, stiffness, and absorbed energy substantially higher than the constant-angle configuration, attributed to tailored thickness buildup and optimized tow steered angles at particular regions of the cylinder. The experimental and numerical results indicate that VAFW designs can be tailored to postpone buckling so that the material strength can be better exploited.
Development of a new generation of filament wound composite pressure cylinders
Composites Science and Technology, 2009
A new generation of composite pressure vessels for large scale market applications has been studied in this work. The vessels consist on a thermoplastic liner wrapped with a filament winding glass fibre reinforced polymer matrix structure. A high density polyethylene (HDPE) was selected as liner and a thermosetting resin was used as matrices in the glass reinforced filament wound laminate.
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.
EXPERIMENTAL CHARACTERIZATION OF FILAMENT WOUND GLASS/EPOXY AND CARBON/EPOXY COMPOSITE MATERIALS
Composites have been used extensively in application such as pipes and pressure vessels. Therefore there is a need for further studies on the properties of these materials. This paper presents the results from a series of tensile tests on the mechanical properties of composite materials. Specimens cut from pipes made from composite materials were tested under internal pressure loadings have been tested by using a series of ASTM Standards test methods for mechanical properties. Based on the results obtained, the longitudinal E 11 , transverse E 22 and shear modulus G 12 of 101.2 GPa, 5.718 GPa, 4.346 GPa and 36.6, 5.4 GPa, 4.085 GPa for carbon and glass fiber/ epoxy composites, respectively, while the ultimate longitudinal X L , transverse X T and shear tensile τ 0 strengths of 1475.4 MPa, 20 MPa, 36 MPa and 618.9 MPa, 14 MPa, 28 MPa for carbon and glass fiber/epoxy composites, respectively. The results from this series of tests have been presented and compared with results from analytical equations. Good agreement was achieved between the experimental results and analytical results.
In this work, damage and failure in carbon fiber reinforced epoxy filament wound composite tubes were thoroughly evaluated through a proposed damage model, which is able to identify different failure modes. Moreover, a non-linear finite element model based on the arc length method was developed. The tubes were manufactured via dry-filament winding using T700 towpregs, and subjected to external pressure tests to evaluate computational analyses. Numerical results indicated that the tubes with a diameter-to-thickness ratio (d/t) lower than 20:1 fail by buckling, whereas the tube [90 ± 55 12 /90], which has a higher d/t ratio presented failure primarily driven by in-plane shear, with delaminations. These results were compared with experimental tests, and relative differences in external pressure strengths were lower than 8.4%. The developed model presented a low computational cost and a very good agreement with experimental results, being very attractive to both academic and industrial sectors.
Composites Part B: Engineering, 2018
Identification of the boundary between failure by buckling, collapse and material failure in cylindrical tubes under axial compression is still challenging. The focus of this research is to investigate the response of carbon/epoxy filament wound cylindrical tubes under axial compression. Three approaches have been studied: (i) linear buckling; (ii) nonlinear buckling; and (iii) progressive damage modeling (PDM). For that, analytical, numerical and experimental approaches have been followed. Key results show that thinner tubes fail by buckling followed by a post-buckling field, whereas material failure due to transverse compression and in-plane shear stresses occur for thicker tubes. Both analytical and linear numerical models predicted very well the critical buckling load for all [±α] tubes, and nonlinear buckling model satisfactorily predicted axial displacement over the loading history. For multilayered tubes, the developed damage model provided better predictions compared to the nonlinear buckling model. Furthermore, for thicker tubes, a hoop layer at the outermost, instead of middle or innermost, improves buckling/compressive resistance.
Theoretical stress and strain distribution across thick — walled filament wound composite
Summary -Monolithic thick cylinder theory with linear elastic orthotropic laminate properties was employed successfully to predict the inside and outside surface strains. While applying the theory to thick-walled tubes it is necessary to consider the different states of stress and strain on the inside and outside surfaces and to consider the effect of radial stress. Three-dimensional stress analysis was used throughout and is presented for general interest in a form suitable for computer application. Numerical example was used to compare the results obtained from the equations with the results obtained with use of CompositePro software and good agreement was achieved between them both. Key words: thick-walled filament wound composite tubes, three-dimensional stress and strain analysis, orthotropic laminate.
Stress Analysis of FRP Composite Cylinder with Closed Ends
IOSR Journal of Mechanical and Civil Engineering, 2013
Composite cylinders made of a polymer matrix such as epoxy reinforced with glass or carbon fibers possess extremely high strength. Proper modeling of FRP composite cylinder is very essential for many applications. FRP composite cylinders are commonly used in the aerospace, automotive, marine and construction industries. The present work is to study the variation of stressesat the top end, middle and bottom end portions of a composite cylinder by varying the diameter to thickness ratio(S) and fiber angle (θ).The four layered angle ply (θ 0 /-θ 0 /-θ 0 /θ 0) composite cylinder is considered forthe present work and behavior of each portion (Top end, middle and Bottom end) is studied.For the present work composite cylinder is modeled in ANSYS and analysis was carried out using numerical software. It isfound thatthe increment of stress takes place linearly with respect to D/t ratio due to reduction in thickness of the layer.The critical fiber angle is 45⁰ to 60⁰ as it offers high resistance against axial and circumferential deformation in middle and end portions.