Filament-wound Pressure Vessels Research Articles

Analysis and optimization of junction between cylindrical part and end dome of filament wound pressure vessels using data driven evolutionary algorithms

The junction between cylindrical part and end dome is the most critical place of the filament wound composite pressure vessels because the shear forces and bending moments occur in this area. The strength analyses of junction between cylindrical part and different types of known end domes based on influence coefficients method were performed for filament wound composite pressure vessels manufactured using glass-epoxy and carbon-epoxy composites. Four known end domes were considered that is, a spherical shell, a geodesic-isotensoid shell, a shell based on minimizing of the Tsai-Hill’s strength criterion and shell designed in authors’ previous work (Hoffman 1 shell). Moreover, the study is also dealing with design of optimal end dome shape which takes account to the junction area. Finding of optimal end dome shape was based on data-driven evolutionary algorithms. Using input dataset from the analytical simulation surrogate models were created using Evolutionary Deep Neural Nets (EvoDN2) algorithm. The multicriterial optimization procedure was performed using Constrained Reference Vector Algorithm (cRVEA) optimization algorithm. Results indicates that the optimal end dome shape highly depend on material properties.

Optimization of dome shape for filament wound pressure vessels using data-driven evolutionary algorithms

ABSTRACT Filament wound glass/epoxy and carbon/epoxy pressure vessels were designed using a data-driven evolutionary approach along with a classical mechanics-based analysis. Analytical solutions for three known end domes (a spherical shell, a geodesic-isotensoid shell and a shell based on minimizing of the Tsai-Hill’s criterion) and end dome based on Hoffman’s criterion were used to create surrogate models through two different evolutionary optimization algorithms: Evolutionary Neural Net (EvoNN) and Bi-objective Genetic Programming (BioGP) and bi-objective evolutionary optimization studies were carried out using them. Composite pressure vessels are manufactured by means of filament (helical) winding. The stresses in the end domes were evaluated analytically and compared with each other. Hoffman strength criterion was chosen for the evaluation of the critical areas of the shells. Moreover, the best dome shape for given material and polar hole/equator ratio was selected for various types of failure.

Estimating S-N curves for local fiber dominated fatigue failure in ring specimens representing filament wound pressure vessels with damage

Modeling the effect of fatigue is important for predicting remaining life of damaged filament wound composite pressure vessels. This study shows how S-N curves can be measured that describe local fiber dominated fatigue failure on the scale of 0.25 mm near stress concentrations caused by a hole representing damage.High frequency Digital Image Correlation DIC was applied to measure strain fields in rings tested by the split disk method. The rings were cut from a glass fiber reinforced polymer pressure vessel. A hole was cut into the rings to simulate damage in the laminate of the pressure vessel.The Miner sum cumulative damage is calculated based on strain histories measured by DIC and several assumed S-N curves. The S-N curve giving Miner sum damage closest to the experimentally observed local failures in several samples is taken as the S-N curve describing the material´s behavior best. The local S-N curve was considerably less conservative than nominal S-N curves obtained from standard coupon testing. Its origin was a factor 2.5 higher.

The Effects of Layer-by-Layer Thickness and Fiber Volume Fraction Variation on the Mechanical Performance of a Pressure Vessel

Abstract Due to high stiffness/weight ratio, composite materials are widely used in aerospace applications such as motor case of rockets which can be regarded as a pressure vessel. The most commonly used method to manufacture pressure vessels is the wet filament winding. However, the mechanical performance of a filament wound pressure vessel directly depends on the manufacturing process, manufacturing site environmental condition, and material properties of matrix and fiber. The designed pressure vessel may not be manufactured because of the mentioned issues. Therefore, manufacturing of filament wound composite structures are based on manufacturing experience and experiment. In this study, effects of layer-by-layer thickness and fiber volume fraction variation due to manufacturing process on the mechanical performance were investigated for filament wound pressure vessel with unequal dome openings. First, the finite element model was created for designed thickness dimensions and constant material properties for all layers. Then, the model was updated. The updated finite element model considered the thickness of each layer separately and variation of fiber volume fraction between the layers. Effects of the thickness and fiber volume fraction on the stress distribution along the motor axial direction were shown. Also hydrostatic pressurization tests were performed to verify finite element analysis in terms of fiber direction strain through the motor case outer surface. Important aspects of analyzing a filament wound pressure vessel were addressed for designers.

A comparative study of two kinds of T800 carbon fibers produced by different spinning methods for the production of filament-wound pressure vessels

A comparative study of two kinds of T800 carbon fibers produced by different spinning methods for the production of filament-wound pressure vessels

Structural Health Monitoring of Pressure Vessel Based on Guided Wave Technology. Part III: Online Monitoring of Filament Wound Pressure Vessel

Structural Health Monitoring of Pressure Vessel Based on Guided Wave Technology. Part III: Online Monitoring of Filament Wound Pressure Vessel

EVALUATION OF OPTIMUM CONFIGURATIONS FOR COMPOSITE OILFIELD THREE-PHASE SEPARATOR PRESSURE VESSEL

Gravity three-phase separators consist of pressure vessel with multiple internals that utilize gravity settlement to separate gas/water/oil free from each other. The pressure vessel represents the substantial element of such separators. Limited work has been reported on investigating fluid contained multilayered filament-wound composite pressure vessels. However, destructive testing with full scale or subscale is the best method to determine the structural characteristics of filament???wound pressure vessels as it requires an excessive cost. In this study, three parametric numerical models have been undertaken to represent three load cases namely; pure pressure, operating, and hydro-test load cases in order to predict optimum lay-up for filament-wound pressure vessels of s???glass/epoxy, carbon/epoxy composite laminates and hybrid of both for certain configurations. ANSYS (ACP) 17.0 commercial software was used for simulation and analysis. ANSYS Workbench design point parameters were used to construct parametric models. A developed mathematical solution used from cited work was employed for results verification using Tsai-Wu failure criterion for the safe design assessment in terms of safety factor. The findings indicate that for operating load case, optimum lay-up should be selected according to foreseen loading ratio acting upon pressure vessel during its lifetime, and hydro-test load case is safe for all studied lay???ups also.

A comparative study of two kinds of T800 carbon fibers produced by different spinning methods for the production of filament-wound pressure vessels

The surface morphologies of two T800 carbon fibers produced from polyacrylonitrile by dry-jet wet spinning and wet spinning were compared. The mechanical properties of Naval Ordnance Laboratory (NOL) rings made from their composites with an epoxy resin matrix, and the strain distributions and hydrostatic breaking pressures of filament-wound pressure vessels produced from them were investigated. Results indicated that dry-jet wet spinning resulted in carbon fibers with a smooth surface while wet spinning gave rise to many surface grooves with uneven widths and depths on the fiber surface. Comparing the two fibers in epoxy resin composite NOL ring tests, those with the wet-spun T800 carbon fibers were more brittle, but had a higher interlaminar shear strength. A filament-wound pressure vessel using the wet-spun T800 carbon fibers was easier to burst at a place located between the dome and the cylinder while that using the dry-jet wet-spun carbon fibers was burst without a preferred broken location in a hydrostatic test. For a 150 mm diameter filament-wound pressure vessel made of the T800 wet-spun carbon fibers, the performance factor (PV/Wc, where P is pressure, V is the volume and Wc is the composite weight) is 34.8 km, which is significantly lower than one made using the T800 dry-jet wet-spun carbon fibers (47.2 km), indicating that the dry-jet wet spun carbon fibers are more suitable for preparing a filament-wound pressure vessel.

Experimental and numerical investigation of the strain response of the filament wound pressure vessels subjected to pressurization test

AbstractThis article presents the strain response of glass fiber reinforced epoxy matrix pressure vessels subjected to pressurization test. Three filament wound composite pressure vessels with different dimensions are manufactured by fiber winding processing, and the pressurization tests of these pressure vessels are performed. The stain of the inner/outer surface of the vessels during the pressurization tests is recorded. A progressive damage model is built based on the 3D Hashin failure criteria by finite element method (FEM) to predict the strain response of the composite pressure vessels. Fundamental mechanical tests that including the tensile, double cantilever beam, and three‐point end notched flexure tests of the composite laminates are carried out to determine the strength and stiffness parameters used in the FEM. The results show that the circumferential strain of the three composite pressure vessels is greater than the longitudinal strain. The maximum stress and strain occurs at the head of the pressure vessels. The predictions of FEM match the experimental results well, and the strain differences between FEM and experiments of the pressure vessels are less than 12%.

In-Situ Monitoring of a Filament Wound Pressure Vessel by the MWCNT Sensor under Hydraulic Fatigue Cycling and Pressurization

As a result of the high specific strength/stiffness to mass ratio, filament wound composite pressure vessels are extensively used to contain gas or fluid under pressure. The ability to in-situ monitor the composite pressure vessels for possible damage is important for high-pressure medium storage industries. This paper describes an in-situ monitoring method to permanently monitor composite pressure vessels for their structural integrity. The sensor is made of a multi-walled carbon nanotube (MWCNT) that can be embedded in the composite skin of the pressure vessels. The sensing ability of the sensor is firstly evaluated in various mechanical tests, and in-situ monitoring experiments of a full-scale composite pressure vessel during hydraulic fatigue cycling and pressurization are performed. The monitoring results of the MWCNT sensor are compared with the strains measured by the strain gauges. The results show that the measured signal by the developed sensor matches the mechanical behavior of the composite laminates under various load conditions. In the hydraulic fatigue test, the relationship between the resistance and the strain is built, and could be used to quantitative monitor the filament wound pressure vessel. The bursting of the pressure vessel can be detected by the sharp increase of the MWCNT sensor resistance. Embedding the MWCNT sensor into the composite pressure vessel is successfully demonstrated as a promising method for structural health monitoring.

A novel structure design of braided composite pressure vessel and its mechanical analysis

A novel structure of braided composite pressure vessel (BCPV) is designed in this paper. Based on the overall geometry structure of braided preform, the representative volume unit (RVU) model is established. The effective elastic constants and the mechanical properties of the composite layer of BCPV are predicted, and compared with filament-wound pressure vessel (FWPV). Numerical results show that BCPV can effectively improve the overall mechanical properties of the composite pressure vessel, and has a wide application prospect.

Design of Optimum Filament Wound Pressure Vessel with Integrated End Domes

In its most general form, a pressure vessel consists of two main parts; the cylindrical part and the dome part. This paper presents the analysis that has been conducted in order to obtain the optimum shape of the filament wound dome part. A composite pressure vessel with optimized dome ends avoids critical stresses that are incorporate with the structure when the structure is internally pressurized. The analysis deals with domes with/without polar opening. Analytical models are developed based on mechanics of materials, geodesic analysis and are solved using numerical techniques. The models can predict both the optimum shape and optimum thickness of the dome part that can safely withstand the applied loads with minimum weight. The results have been verified using published work with good agreement. Finally, the models have used to investigate the effect of changing material type, material properties on the optimum shape of the dome part.

Performance index optimization of pressure vessels manufactured by filament winding technology

Filament-wound pressure vessels represent the proper choice to obtain good mechanical properties and lightweight. The pressure vessel geometry is generally cylindrical and the wall is composed of a ‘liner’ and a ‘shell.’ The liner holds the gas and guards the shell from chemical attacks. The filament-wound shell aims to withstand the hydrostatic load of pressure gas. The shell design has to be defined in observance of both fibers stratification methodology and design structural criteria. For years, pressure vessel design primarily focused on mass; space saving features during pressure vessel design was usually a secondary concern unless specifically required by the customer. Now, more emphasis have being assigned to design light weight pressure vessels that also maximizes use of available space for industry finding such as space on a spacecraft, as well as mass, is at premium. For this reason, it is very important to optimize together the index of performance and packaging of gas storage system. This work aims to develop a parametric method to optimize the index of performance as a function of one or more pressure vessels; in this way, it is possible to optimize also the packaging of the gas storage system.

Predicting Structural Behavior of Filament Wound Composite Pressure Vessel Using Three Dimensional Shell Analysis

Fiber reinforced polymer composite materials with their higher specific strength, moduli and tailorability characteristics will result in reduction of weight of the structure. The composite pressure vessels with integrated end domes develop hoop stresses that are twice longitudinal stresses and when isotropic materials like metals are used for development of the hardware and the material is not fully utilized in the longitudinal/meridional direction resulting in over weight components. The determination of a proper winding angles and thickness is very important to decrease manufacturing difficulties and to increase structural efficiency. In the present study a methodology is developed to understand structural characteristics of filament wound pressure vessels with integrated end domes. Progressive ply wise failure analysis of composite pressure vessel with geodesic end domes is carried out to determine matrix crack failure, burst pressure values at various positions of the shell. A three dimensional finite element analysis is computed to predict the deformations and stresses in the composite pressure vessel. The proposed method could save the time to design filament wound structures, to check whether the ply design is safe for the given input conditions and also can be adapted to non-geodesic structures. The results can be utilized to understand structural characteristics of filament wound pressure vessels with integrated end domes. This approach can be adopted for various applications like solid rocket motor casings, automobile fuel storage tanks and chemical storage tanks. Based on the predictions a composite pressure vessel is designed and developed. Hydraulic test is performed on the composite pressure vessel till the burst pressure.

Finite element analysis of filament-wound composite pressure vessel under internal pressure

In this study, finite element analysis (FEA) of composite overwrapped pressure vessel (COPV), using commercial software ABAQUS 6.12 was performed. The study deals with the simulation of aluminum pressure vessel overwrapping by Carbon/Epoxy fiber reinforced polymer (CFRP). Finite element method (FEM) was utilized to investigate the effects of winding angle on filament-wound pressure vessel. Burst pressure, maximum shell displacement and the optimum winding angle of the composite vessel under pure internal pressure were determined. The Laminae were oriented asymmetrically for [00,00]s, [150,-150]s, [300,-300]s, [450,-450]s, [550,-550]s, [600,-600]s, [750,-750]s, [900,-900]s orientations. An exact elastic solution along with the Tsai-Wu, Tsai-Hill and maximum stress failure criteria were employed for analyzing data. Investigations exposed that the optimum winding angle happens at 550 winding angle. Results were compared with the experimental ones and there was a good agreement between them.

Experimental and analytical approach for the size effect on the fiber strength of CFRP

AbstractIn this article, experimental test and an analytical approach were conducted to verify the fiber tensile strength of filament wound pressure vessel. As a test method, improved hoop ring test method was considered. From a series of fully scaled hoop ring tests, the size effect showed the clearly observed tendency toward fiber strength degradation with increasing stressed volume. As an analytical method, Weibull weakest link model and the sequential multistep failure model (SMFM) were considered and compared with the test data from hoop ring test and unidirectional specimens test. It was found that the Weibull weakest link model and the SMFM significantly overestimate the size effect on fiber strength. Thus, the fiber strength showed much lower values than those of test data. In this study, an improved SMFM was proposed by considering a modification of the length size effect. Because this model enhances the accuracy of predicting the fiber strength, the fiber strengths from the improved SMFM showed good agreement with the test data.POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers

Research on Homogenization of Composite Materials

A numerical model is given to identify equivalent parameters of composite materials, using BP neural network algorithm. Taking Filament-wound composite pressure vessels as the research object, finite element models are first constructed .Getting node displacements as network training samples, the mechanical parameters as output information of network for effective training, the equivalent material parameters can be obtained. The satisfactory numerical validation is given and results show that the proposed method can identify the equivalent modulus and the equivalent Poisson’s ratio of the Filament-wound composite pressure vessels with precision. The computational efficiency is improved with BP neural network.

Semi-Geodesics-Based Dome Design for Filament Wound Composite Pressure Vessels

In this paper we apply semi-geodesic trajectories to the creation of isotensoid domes for filament wound pressure vessels. The governing equations for the determination of the meridian shapes and related winding angle distributions of domes are derived using the netting analysis and the semi-geodesic winding law. The effects of the slippage coefficient on the geometry and fiber trajectories of the domes are respectively evaluated in terms of the resulting meridional curves and fiber angles. It is revealed that the semi-geodesic angles and the dome depth have an overall decrease with increasing the slippage coefficient. The results also demonstrate that the use of semi-geodesics significantly enlarge the design space for the geometry and adapted fiber trajectories of the domes. The present method can provide a significant reference for the design and production of the domes for semi-geodesically overwound pressure vessels.

Visual indicator for the detection of end-of-life criterion for composite high pressure vessels for hydrogen storage

A model to predict the accumulation of fibre breaks in advanced composites, that takes into account all physical phenomena implicated in fibre failure (i.e. the random nature, stress transfer due to breaks, fibre debonding and viscosity of the matrix) shows clearly that the failure of a unidirectional composite structure results in the formation of random fibre breaks which at higher loads coalesce into clusters of broken fibres. This stage of development is followed almost immediately by failure. This has direct application to filament wound pressure vessels of the type used to store hydrogen under high pressure. A novel, cost effective, method of revealing developing unreliability in advanced composite pressure vessels is presented.

A multiscale modeling approach to analyze filament-wound composite pressure vessels

A multiscale modeling approach to analyze filament-wound composite pressure vessels is developed in this article. The approach, which extends the Nguyen et al. [Prediction of the elastic-plastic stress/strain response for injection-molded long-fiber thermoplastics. J Compos Mater 2009; 43: 217–246.] model developed for discontinuous fiber composites to continuous fiber ones, spans three modeling scales. The microscale considers the unidirectional elastic fibers embedded in an elastic–plastic matrix obeying the Ramberg–Osgood relation and J2 deformation theory of plasticity. The mesoscale behavior representing the composite lamina is obtained through an incremental Mori–Tanaka [Average stress in matrix and average elastic energy of materials with misfitting inclusions. Acta Metall 1973; 21: 571–574.] type model and the Eshelby [The determination of the elastic field of an ellipsoidal inclusion and related problems. Proc R Soc Lond, Ser A 1957; 241: 376–396.] equivalent inclusion method. The implementation of the micro–meso constitutive relations in the ABAQUS® finite element package (via user subroutines) allows the analysis of a filament-wound composite pressure vessel (macroscale) to be performed. Failure of the composite lamina is predicted by a criterion that accounts for the strengths of the fibers and of the matrix as well as of their interface. The developed approach is validated in the analysis of an aluminum liner – T300 carbon/epoxy pressure vessel to predict the burst pressure. The predictions compare favorably with the numerical and experimental results by Lifshitz and Dayan [Filament-wound pressure vessel with thick metal liner. Compos Struct 1995; 32: 313–323]. The approach will be further demonstrated in the study of the effects of the lamina thickness, helical angle, and fiber–matrix material combination on the burst pressure.