Filament Wound Composite Pipes Research Articles

Progressive fatigue modelling of composite pipes with a hole

Composite pipes are increasingly used in demanding applications thanks to their light weight and corrosion resistance. To manage their integrity, tools able to predict their fatigue life and residual properties under cyclic loads are required. A finite element progressive fatigue model was applied to filament-wound composite pipes with a hole submitted to tensile cyclic fatigue. The fatigue model combined continuum damage mechanics for intra-laminar failure mechanisms and cohesive zone modelling for inter-laminar and selected macroscopic cracks. A linear fatigue damage accumulation law was used along with an empirical sudden-death residual strength model, relying solely on the material S-N curve. The fatigue simulation was conducted by an external cycle-jump procedure. After calibration on one load level, the model was able to describe the fatigue life at other load levels within one standard deviation (0.63 decade) of the experiments and resulted in a S-N curve slope of −0.084 while the experimental one was −0.072.

An analytical solution for dynamics of cyclic thermomechanically loaded multi-layered filament-wound composite pipes in hygrothermal environment

In this study, an analytical solution is provided to present the stress and strain analyses of the multi-layered filament-wound composite (MLF-WC) pipes subjected to the cyclic internal pressure and cyclic thermal loading in hygrothermal environment. The MLF-WC pipe is made of anisotropic, homogeneous and linear elastic materials. It is assumed that the material properties are temperature-independent. Also, applied cyclic loadings are independent of the tangential and axial coordinates. Using the three-dimensional anisotropic elasticity, time-dependent analytical expressions are provided for the stresses, strains and displacements. The accuracy of present analytical approach and numerical results is verified by comparison with those given in literature. It is remarked that the developed analytical solution can be used for the dynamic analysis of functionally graded pipes and pressure vessels under the cyclic loadings. Moreover, through the numerical results, it is found that stacking sequence has a considerable effect on the distributions of shear strain and stress. Furthermore, for the MLF-WC pipe under simultaneous cyclic internal pressure and cyclic thermal loading, the mean amplitudes of the cyclic loadings have a significant effect on the sign of axial strain.

Solid Particle Erosion Behavior on the Outer Surface of Basalt/Epoxy Composite Pipes Produced by the Filament Winding Technique

Basalt/epoxy composite pipes in a [±55]4 winding configuration were produced on CNC filament winding machines (10 N fiber tension and ~11 mm bandwidth). In the experiments, a 34 m/s impact velocity was set using the double-disc method, and five different particle impingement angles (30, 45, 60, 75, and 90°) were used to determine the erosive effect on the outer surfaces of filament wound composite pipes under the influence of 600 μm erodent particles with angular geometry in the test set, complying with the ASTM G76-95 standard. The winding patterns in the lamina (±55 angle-ply laminate region) and zigzag (±55 zigzag region) regions of BFR/EP pipes were determined to have significant effects on solid particle erosion resistance, as evidenced by the SEM images.

Modeling Large-Surface Impact-Induced Damage in Iteratively Characterized Filament-Wound Composite Pipes: A Numerical and Experimental Investigation

With the widespread use of fiber reinforced polymer (FRP) composite pipes, their susceptibility to impact damage remains a significant cause of concern. This work investigates the structural response and damage propagation of glass-fiber reinforced epoxy (GRE) pipes under large-surface low-velocity impacts. A series of drop-weight impact tests of varying heights is conducted and compared to numerical finite element (FE) simulations. Then, plies are individually modeled and assigned with properties obtained from the authors’ earlier work. Utilizing composite failure theories and mixed-mode delamination theories, the simulated structural responses including the load–displacement, strain–displacement response and damage propagation are compared and validated with the experimental results. It was found that the structural response is well predicted at higher drop heights and there is a significant change in damage type and propagation with increasing drop heights. The proposed approach builds on the authors’ earlier work and provides a modeling approach for the prediction of structural response, inter- and intra-laminar damage with just pipe level properties.

Filament wound pipes optimization platform development: A methodological approach

A multi-objective and multi-level optimization procedure is developed for obtaining optimal structural design of filament wound composite pipes in oil and gas industries. At the first stage, regulated design constraints are identified. Required computational tools for predicting structural properties of the composite pipes are developed and validated through experimental study. Then, the pipe design procedure is formulated as an engineering optimization problem where a hybrid design-optimization platform is developed to deal with that. The platform integrates multi-objective genetic algorithm on level 1 with a premutation-based direct search approach on level 2. It is aimed to minimize the cost of the pipe while maximum values for other structural properties are expected. Manufacturing limitations are also taken into account as the constraints in addition to design requirements.

Theoretical and Experimental Analysis of Inter-Layer Stresses in Filament-Wound Cylindrical Composite Structures.

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 ring into a split ring, which acts on the internal surface of the tested cylindrical sample, was selected. The operation of the test rig (test stand) was simulated using the Finite Element Method (FEM). Measurements with strain gauges were conducted during the experiments.

Effect of Basalt Intraply Fiber Hybridization on the Compression Behavior of Filament Wound Composite Pipes

Abstract The current study deals with the effect of basalt fiber hybridization on the compressive properties of composite pipes reinforced with glass fiber and carbon fiber. Hybrid and non-hybrid fiber reinforced pipes (FRPs) were fabricated through wet filament winding technique. Intraply fiber winding structure in which different fiber types were simultaneously wound at the layer was employed for the hybridization. The FRP samples wound by different fiber winding angles (± (40°), ± (55°), ± (70°)) were prepared in order to gain a better insight on the influence of basalt intraply fiber hybridization. The compression properties of FRP samples were experimentally determined by quasi-static compression tests using external parallel-plates for both the axial and radial directions. The non-hybrid carbon FRP pipes showed the maximum axial compression strength in parallel to the highest strength and lowest ductility of carbon fibers, while the minimum axial compression strength was obtained for the non-hybrid pipes reinforced with basalt fibers that, in comparison, exhibit much less strength and higher ductility. The pipes submitted to the axial compression tests predominantly failed due to the development of cracks and buckling along the fiber direction. While the inclusion of basalt fiber reduced the axial compression behavior of the non-hybrid carbon and glass FRP samples, it improved that behavior in the radial compression tests. Delamination was determined as the major failure mode for the damaged FRPs under radial compression. It is found that the incorporation of basalt fiber provides improvements in radial compression properties as opposed to axial compression properties and in the same manner the increment in fiber winding angle makes a positive contribution to radial compression properties.

The Numerical Approach to Mosaic Patterns in Filament-Wound Composite Pipes

This paper is focused on radial-compression of filament-wound composite pipes. An important but frequently disregarded is the issue of the choice of the winding pattern. The influence of the pattern on the strength of pipes is the subject of the investigation. Since the real geometry of filament-wound tubes is complicated researchers use simplified models (especially in “zig-zag” area), which are insufficient to reflect real behavior of tubes. An attempt to investigate a more precise geometry is presented in this work. A python script is used to model the particular areas typical for filament-wound elements. Hashin criterion is used to reflect damage in the material during compression. Results of numerical simulations are discussed and compared with experimental from other researchers. Based on the prepared model – the influence of pattern on the strength of a composite pipe is possible. Although some improvements may be introduced, a satisfactory agreement between the experiment and numerical simulation was achieved.

An experimental investigation on lateral crushing response of glass/carbon intraply hybrid filament wound composite pipes

The current study aimed to examine an experimental investigation on the energy absorption capability of glass/carbon intraply hybrid filament wound composite pipes subjected to quasi-static lateral compression loading. The composite pipes with different fiber orientation angles were fabricated for both hybrid and non-hybrid to systematically analyze the performance of intraply hybridization process. At least 5 samples of each composite pipe configuration were tested to obtain the load–displacement curves and fracture patterns. The failure modes and fracture mechanisms of crushed samples were discussed to establish the influence of hybridization on crashworthiness parameters through load–displacement response. Separation between the layers (delamination) was occurred as the main damage mechanism in all samples. Hybridization with glass fiber significantly increased the energy absorption capability and load carrying capacity of carbon fiber-reinforced composite pipes. Their crushing values were found as between the values of pipes made of glass fiber and carbon fiber as expected. Furthermore, hybridization provided to opportunity of more stable load–displacement response for crushing process. An increment in fiber orientation angle was also led to increase in energy absorption capability and load carrying capacity. The pipe made of glass with higher fiber orientation had the best specific energy absorption.

Experimental investigation of cooling conditions, MWCNTs and mandrel diameter effects on the thermal residual stresses of multi-layered filament-wound composite pipes

This study employs numerical and experimental approaches to analyze effects of various filament-winding parameters, including mandrel diameter and cooling conditions, on the process-induced thermal residual stresses of composite and nanocomposite pipes. Simultaneous effects of the addition of multi-walled carbon nanotubes (MWCNTs) and the cooling conditions were also analyzed in detail. To accomplish this aim, a few composite and nanocomposite cylinders with various diameters in different cooling conditions were produced using filament-winding process and experimented. The incremental hole-drilling method using an integral inverse solution was employed for measuring the curing-induced residual stresses. The experimental findings confirm that using MWCNTs for reinforcing the matrix, choosing a slow cooling condition, and increasing the diameter generate less residual stresses during the process. Moreover, this study clearly showed that the addition of MWCNTs decreases the sensitivity of the structure to the effects of cooling conditions during the curing process. Therefore, finding optimum amounts of MWCNTs and cooling rate leads to the minimum cost of fabrication.

Pressure response and life assessment of filament-wound composite pipes after impact

This paper presents the results of drop-weight impact (5 J–150 J), quasi-static indentation, and post-impact internal pressure testing of a ±55°, filament-wound, glass fibre reinforced epoxy (GRE) pipe. The void content in the tested pipes was quantified by optical and stereo microscopy image analysis and ranged from 5% to approximately 13%. The void content was found not to influence the damage area, or the observed damage mechanisms, following impact loading. However, the void content was found to greatly affect the damage tolerance of the pipe during the pressure testing following an impact. It is established that impact damage area alone is not enough to determine the reduction in pipe failure performance under internal pressure. After impacts at low energies, a number of the tested pipes surpassed the operating pressure of the pipe during pressurisation (no leakage occurred). In these instances, an industry accepted regression gradient was used to determine the pipe's residual life, which estimated the reduction in service life from 20 years to less than two years. The quasi-static indentation testing confirmed that low energy impact behaviour (<20J) is largely equivalent to a quasi-static event under the tested constraints. Fabrication induced voids and their interaction with impact damage, are currently not considered by the existing testing standards (BS EN ISO 14692), but according to this investigation may influence the safe continued use of a GRE pipe subjected to internal pressure.

Experimental investigation and damage simulation of large-scaled filament wound composite pipes

This paper investigates the progressive collapse of filament wound Toray T700/Epotech X4201 composite pipes with various layups via a combined experimental and numerical study. The experimental program examines the flexural behavior of full-diameter T700/X4201 pipes under four-point bending and the tensile behavior of filament wound coupon specimens cut from the pipes. The tests show that the composite layup significantly influences the deformation, flexural resistance, and failure mechanisms of the composite pipes. The CFRP pipe with the optimal complex layup [(90/±15/90/±453)5/±453] design has higher ultimate resistance in bending than other designs with layups of [±45]28 and [90]56. Coupon tests show similar effects of composite layup on the tensile behavior of coupon specimens. The numerical effort evolves a three-dimensional progressive damage model to predict the failure in the CFRP coupons and pipes. The damage model incorporates a nonlinear in-plane shear behavior of the T700/X4201 composite material prior to damage initiation and uses a continuum damage mechanics approach to model the matrix and fiber damage progression in the composite pipes. The combined experimental-numerical work provides a more complete understanding of the bending behavior of large-scaled composite pipes, showing distinct failure modes for filament wound pipes with different layups. The load-displacement curves, ultimate bending resistance and failure modes of the composite pipes with different layups are accurately captured using the proposed damage model, demonstrating the capability for the failure analysis of large-scaled composite pipes such as composite risers in offshore applications.

DEVELOPMENT OF TUBULAR WOVEN PREFORM REINFORCED COMPOSITE PIPE AND COMPARISON OF ITS COMPRESSION BEHAVIOR WITH FILAMENT WOUND COMPOSITE

In this research a novel preform for the reinforcement of tubular composite structures has been developed. The mentioned preform was woven from para aramid yarn in the tubular form. A mandrel was passed through a certain amount of tubular woven preform layer then impregnated with resin, cured in an oven and the resulting composite pipe was removed from the mandrel. By using the same para aramid yarn, filament wound composite pipes were also manufactured with the same production parameters. Axial and transverse compression behaviors of tubular woven preform reinforced composite pipes were compared with the ones that are manufactured by conventional filament winding method. The test results indicated that under transverse and axial compression, composite pipes developed in this study showed superior strength values than filament wound ones.

An experimental study on intraply fiber hybridization of filament wound composite pipes subjected to quasi-static compression loading

Abstract This paper aimed to explore the failure modes and crashworthiness characteristics of intraply hybridized fiber reinforced pipes (FRP) made of basalt and glass fiber reinforcements subjected to quasi-static compression loading. Experimental investigations were performed on various fiber orientation angles (±40°, ±55°, and ±70°) of the basalt FRP, glass FRP and hybridized basalt/glass FRP, fabricated by filament winding technique. Fracture mechanisms of pipe samples were discussed to understand failure modes. Three distinct failure modes as transverse shearing, lamina bending, and local buckling were observed in crushing tests. Hybridized samples proved to fix instability deficiency of pipes by exhibiting the progressive failure as combination of transverse shear and lamina bending crushing modes. Also, experimental results belong them within the range of pipes made of glass and basalt fiber data's as expected. In the view of fiber orientation aspect, decrease in winding angle resulted with the significant increase of energy absorption capability of all pipes. The pipes made of glass fiber showed the best specific energy absorption characteristics with the lowest crushing load efficiency.

Hoop tensile and compression behavior of glass-carbon intraply hybrid fiber reinforced filament wound composite pipes

Abstract The current study presents an experimental investigation aimed at exploring the effects of intraply fiber hybridization on the apparent hoop tensile and compression behavior of glass/carbon filament wound composite pipes by conducting split-disk and external parallel-plate loading tests, respectively. The efficiency of the hybridization process is also analyzed for a variation in fiber orientation by preparing composite pipes of different winding angles. The results show that a deterioration occurs in the apparent tensile strength of hybrid composites because of the weak interfacial adhesion between carbon and glass reinforcements. However, the compression behavior of glass fiber wound composite pipes, in terms of pipe stiffness and the stiffness factor, increases with the inclusion of carbon fiber. The increase in pipe stiffness and the stiffness factor are in the range of 10 and 20 %, respectively. Failure modes of the samples have also been discussed to understand fracture mechanisms. In conclusion, the intraply hybridization exercises significant influence, especially in the apparent hoop tensile characteristics of the pipes.

Investigating the influence of delamination on the stiffness of composite pipes under compressive transverse loading using cohesive zone method

The effect of delamination on the stiffness reduction of composite pipes is studied in this research. The stiffness test of filament wound composite pipes is simulated using cohesive zone method. The modeling is accomplished to study the effect of the geometrical parameters including delamination size and its position with respect to loading direction on stiffness of the composite pipes. At first, finite element results for stiffness test of a perfect pipe without delamination are validated with the experimental results according to ASTM D2412. It is seen that the finite element results agree well with experimental results. Then the finite element model is developed for composite pips with delaminated areas with different primary shapes. Thus, the effect of the size of delaminated region on longitudinal and tangential directions and also its orientation with respect to loading direction on delamination propagation and stiffness reduction of the pipes is assessed.

Evaluation of thermal residual stresses of thin-walled laminated composite pipes to characterize the effects of mandrel materials and addition MWCNTs

This research focuses on finding the effects of the addition of multi-walled carbon nanotubes (MWCNTs) and using various mandrel materials on the ply-level thermal residual stresses of thin-walled laminated filament-wound composite pipes. To accomplish this objective, a few specimens were made by considering two various weight fractions, containing 0 and 3%, for MWCNTs and two various mandrel materials, containing aluminum and steel. This study employed the incremental hole drilling method using integral inverse solution for measuring the thermal residual stresses within the structure. This method contains simulation and experimental parts, which both were explained in details entirely. This paper presents analytical discussions and the experimental results to clarify achievements. The results confirmed that adding MWCNTs, as a thermal expansion compensator, to the epoxy matrix modifies the thermal behavior of the epoxy matrix and reduces the thermal residual stresses in the composite pipes. Also, the results show that the residual stresses are strongly affected by the mandrel thermal expansion coefficient. In this case, for example, the specimen manufactured by the steel mandrel experiences less residual stresses compared to which manufactured by the aluminum mandrel.

Material characterization of filament-wound composite pipes

In obtaining mechanical properties of filament-wound fibre reinforced plastic pipes, standardized tests are often used to obtain bulk properties. Being a laminated composite, individual layers of the lamina will behave differently and therefore pipe-level characterizations are usually unable to fully describe the localised responses in detail. Unlike flat composite layups, obtaining unidirectional ply properties in cylindrical filament-wound composites is not as straight-forward. In this work, the composite pipe stress homogenization theory was applied in reverse to obtain the corresponding ply properties in the filament-wound pipe through successive iterations towards experimentally obtained bulk properties. Initial estimates of ply properties were obtained through a combination of extensive literature search and applications of micromechanics theories. With the iterated ply properties, finite element models simulating the tests used to obtain bulk properties were performed to validate the accuracy of the material properties. In addition, additional validation was performed on a smaller pipe section to evaluate the scalability of using ply properties across pipes of different dimensions. It was found that the ply properties obtained was able to accurately predict the responses for pipes of various dimensions.

Investigation of the effect of stacking sequence on low velocity impact response and damage formation in hybrid composite pipes under internal pressure. A comparative study

Filament wound hybrid composite pipes can expose to impact loading from various causes during their service life which can cause an invisible level of damage. Thus, revealing the effect of impact damage gains great importance to design hybrid composite pipes with enhanced damage tolerance. Based on this motivation, the low velocity impact (LVI) response of carbon/glass hybrid filament wound composite pipes has been studied. Hybrid pipes were produced with the winding angle of ±55° by using glass and carbon fiber layers in various stacking sequences by filament winding method. The stacking sequence configurations were set as Carbon/Glass/Glass (CGG), Glass/Carbon/Glass (GCG) and Glass/Glass/Carbon (GGC). Before generating impact damage, an internal pressure of 32 bar was applied to the hybrid pipes in accordance with ANSI/AWWA C950 standard and pre-stress was generated in the pipes. Following, the hybrid pipes subjected to internal pressure were subjected to low velocity impact tests at energy levels of 5, 10, 15 and 20 J. The variation of contact force versus time, contact force versus displacement and energy versus time were obtained. After the testing, the effects of stacking sequence upon damage formation and damage progression under LVI loading have been evaluated based on the obtained data and microscopic analysis. It has been found that the damage formation such as matrix cracking on outer/inner surfaces, radial cracks, delamination, transfer cracks, splitting and leakage can take place. Moreover, the hybrid pipes with CGG stacking represents higher impact resistance while the GCG stacking has a better response of damage formation since this stacking does not show leakage damage.

Experimental and statistical analysis of low velocity impact response of filament wound composite pipes

Abstract Nowadays, filament wound composite pipes (GRP) are used as a structural element in many applications such as natural gas and oil transmission lines, and portable bridge constructions for military purposes. GRP pipes can expose to impact loading from various causes. This loading can cause an invisible level of damage. Thus, the detection and evaluation of such damages are of great importance. In this study, the low velocity impact response of (±55°)3 filament wound E-glass/epoxy composite pipes has been studied. The pipes have been subjected to drop weight impact loading with various impact energies. The force-time and force-displacement relations have been examined. The impact damage formation was also evaluated. It is concluded that the damage development in the pipes is controlled by displacement trough radial direction. The obtained results were evaluated statistically by means of Weibull approach. Microscopy analysis of impacted region revealed that debonding, radial cracks, transfer cracks and delamination damage modes are the main observed damage modes.