Filament Winding Process Research Articles

A novel model for buckling of composite shell: Ring stiffened shell and stiffened shell with cutout under hydrostatic pressure

Focusing on buckling problem under hydrostatic pressure of ring stiffened shells and shells with stiffened cutout fabricated by filament winding process, a new form of equilibrium equations is given in this paper based on high-order shear deformation theory (HSDT). A novel theoretical model is proposed based on Messager's model of geometrical imperfection. The model contains both ring stiffened shell model (RSSM) and stiffened shell with cutout model (SSCM). In this model, changes in the shells' thickness z˜k(x,y),k=1,2,…,n are described using a Fourier series representation, which is included in HSDT stiffness matrix A, B, D, E, F, H. To evaluate the critical buckling pressure pcr, the model is applied and compared with the conventional stiffened cylindrical shell (SCS) model. The results demonstrate a significant reduction in error, ranging from 71.08% to 81.22%, when using the proposed model for shells stiffened by a ring stiffener in the middle, as compared to the SCS model. This highlights the enhanced accuracy provided by the proposed model. The results indicate that small stiffened cutouts in thin shells and large stiffened cutouts in moderately thick shells have relatively small influence on the critical buckling pressure. Conversely, the presence of a ring stiffener in the middle has a more pronounced effect.

On the winding pattern influence for filament wound cylinders under axial compression, torsion, and internal pressure loads

An intrinsic characteristic of components manufactured by the filament winding process is a winding pattern formation during the processing. This paper aims at unlocking and understanding how the winding pattern influences the mechanical behaviour of filament wound cylinders under different boundary conditions. To realize this, a series of finite element models followed by an original geometric approach to generate the pattern are herein developed. Four different patterns and six different winding angles are modelled. These are also modelled by varying the number of layers towards understanding whether there is a correlation between the pattern and the number of layers or not. Three loading cases are considered: axial compression, pure torsion, and internal pressure. Key results reveal that the more layers are stacked to the cylinder, the less impactful is the winding pattern to all loading cases herein investigated.

A fast and precise filament winding path planning method based on discrete non-iterative semi-geodesic algorithm for all applicable mandrel

Obtaining reliable and stable winding paths for complex shapes with current filament winding technologies is still a challenge. Aiming at a practical design of the filament winding process, a novel discrete non-iterative semi-geodesic (NIS) algorithm is proposed, in which a first-order ordinary different equation (ODE) of the tangent vector is directly solved over triangle meshes and then the tangent vector is parallel transported along a geodesic path. Compared to the existing discrete iterative semi-geodesic algorithm, the NIS algorithm does not require trial-and-error to determine the next path point and the time complexity of the NIS algorithm to generate a semi-geodesic path is O(n). The relative error of the NIS algorithm compared with analytical method is less than 1% in terms of mandrel’s rotation angle and winding angle. Then, a complete discrete winding path planning method based on the NIS algorithm is presented, including constant-wall-thickness winding paths at regular winding region, semi-geodesic winding paths at return regions and certain winding pattern construction. This winding path planning method does not require knowledge of the parametric equations of mandrel and is particularly useful for designing winding path for all applicable mandrels, such as vessel, rocket motor and so on.

Experimental investigation on void and compressive response of CNTs reinforced filament-wound riser with metal liner

This study aims to explore the morphology of void and compressive performances of CNTs-reinforced filament-wound risers under axial compressive loading. The porosity morphology and distribution induced by the filament winding process were measured and analyzed, revealing a transition from nearly circular to elongated voids with gradual growth in the size of the individual void as the winding angle increased. Failure modes of composite risers were comprehensively discussed to understand the progressive failure process and load-bearing capacity. The results indicated that failure mechanisms of composite risers mainly manifest as initial resin splitting at the end of the structure, cracks growing in the interwoven region and local buckling at the end of the structure, and local asymmetric buckling as winding angle increased. While the addition of CNTs enhances the brittleness of the substrate and leads to an increased probability of debonding and delamination. Furthermore, the experiment results demonstrate that the energy absorption capacity can be generally improved at larger winding angles for the composite riser with 3% and 5% of CNTs volume content. The maximum values of peak crushing load, mean crushing force, energy absorption, and specific energy absorption were observed in the circumferentially wound riser with 5% of CNTs volume content.

Efficient strategies for reliability analysis and uncertainty quantification for filament-wound cylinders under internal pressure

Induced uncertainties during the filament winding process may cause a significant stochastic variation in the mechanical behaviour of composite shells. This paper aims to develop a novel and deep uncertainty quantification (UQ), sensitivity and reliability analyses of filament wound shells considering manufacturing uncertainties. Firstly, a progressive damage analysis is performed to estimate their deterministic burst pressure. Then, a signal-to-noise (SNR) approach is employed using the Taguchi method for sensitivity analysis and screening uncertainties arising from manufacturing. Initial results reveal that the shells are more sensitive to thickness uncertainties for thinner structures. Then, probabilistic and reliability analyses are carried out using the Boosted Decision Trees Regression (BDTR) approach from machine learning algorithms. Despite the complexity and non-linear relationships in the problem, the developed BDTR-based metamodel shows powerful predictive performance. A comparative study shows that ply thickness uncertainty leads to a significant underestimation of failure probability. For expensive and time-consuming models in that only a few runs can be affordable, a modified approximation method for reliability analysis is proposed. Results indicate a high capability at estimating failure probability with high accuracy.

Dynamic Elastic Modulus Variability in Anisotropic and Isotropic Materials: Comparison by Acoustic Emission

This study compared the variation of the dynamic elastic modulus (E) of three types of composite pipes made by the filament winding process and a steel alloy specimen, according to signal source changes. The specimens were produced with three different winding angles, i.e., ±50°, ±52.5°, and ±55°. The moduli were obtained through a known signal source and the angular variation, according to two sensors positioned over the specimen's surface. In a previous article, the variation in the velocity of acoustic emission (AE) signals, performed in the same type of pipes, was discussed based on the standards for glass fiber-reinforced epoxy (GFRE) filament wound specimens. This work took these preliminary findings to compare with the results found for steel alloy pipes (SAE 1020). This data was used with appropriate equations to determine the dynamic elastic moduli of each material. It was found that, even for small angular differences, the modulus changes position concerning the lamination angle. Thus, the lower the quality control, the lower the final product with composite materials. As expected, for isotropic materials such as steel alloys, the modulus remains constant along the angles, while for anisotropic ones, it is dependent on the principal directions of stress and strain, or on the other hand, dependent on the correlation between the angular wave velocity of the AE signals.

Identification of the characteristics of helicoidally filament wound tubes using vision systems

As the novel technologies regarding the new generation of fuel transportation and stocking are emerging, the filament winding process appears to be a promising fabrication technique for creating reliable pressure vessels that incorporate a pre-impregnated reinforcing structure. The same method can be applied to any axial symmetric component such as tubes, tow bars and generally tubular composite structures. While the composite filaments are being wound, many factors may influence several parameters that are directly related to the overall mechanical performance of the structure, such as voids in resin-reach areas, variation of the filament angle in values outside of the ones desired, and gaps between subsequent filaments placed together. In the present work, an experimental study is presented in which the potential of a vision system is exploited for detecting such kind of defects that are formed in filament winded tubes. This kind of systems may be used for optical inspection and quality control, as well as for monitoring the component during the process. Gaps between filaments and the winding angle are retrieved after scanning the tubes and several observations are presented about the variation of them throughout the length of the tube.

Evaluation of Thermal Adsorption and Mechanical Behaviour of Intralaminar Jute/Sisal/E-Glass Fibre-Bonded Epoxy Hybrid Composite as an Insulator

A thermal gravimetric analyzer analyzed the thermal adsorption properties of developed composites with the temperature range of 28°C–650°C at a 20°C/min constant heat flow rate. The epoxy hybrid composites were synthesized using natural jute/sisal fibre hybridized with the addition of synthetic E-glass fibres at 0-degree, 0/90-degree, and intralaminar orientations through the wet filament-winding process. The effects of orientations on tensile, flexural, and impact strengths of epoxy hybrid composites were studied using ASTM D3039, D790, and D6110. The evaluated results were compared, and the epoxy hybrid composite containing intralaminar orientations found better thermal stability with reduced weight loss at 650°C. Similarly, the test result for mechanical studies of the hybrid composite showed superior tensile, flexural, and impact strengths. The epoxy hybrid composite with intralaminar orientation was found to have a maximum tensile, impact, and flexural strength of 61.91 MPa, 770.61 J/m, and 83.90 MPa, respectively.

Inner blast response of fiber reinforced aluminum tubes

In this work, the dynamic failure of Fiber Reinforced Metal Tubes (FRMTs) under inner blast load was experimentally investigated. The FRMTs was prepared by winding the basalt fiber or H-glass fiber onto the aluminum lining through filament winding process. The influence of explosive mass, winding angle and number of layers on the failure modes of FRMTs were obtained and discussed. The results showed that the fiber reinforced metal tubes performed better anti-blast performance compared to metallic tubes, in terms of deformation amount and failure severity. The FRMTs with winding angle of ±55° provided the best anti-explosion performance under inner blast as a result of the balance between circumferential and axis stresses, and the blast resistance can further be enhanced by optimizing the circumferential strength of inner layers through changing the inner winding angle. With higher strength and flexibility, the H-glass fiber reinforced metal tube had less penetration cracks, small expansion ratio and axial deformation width compared with basalt fiber reinforced metal tubes. It is believed that the current study can be a good reference for the design of fiber reinforced metal tubes or vessels.

Influence of fiber tension during filament winding on the mechanical properties of composite pressure vessels

During the manufacturing of composite pressure vessels, the fiber tension of the filament winding process has an important influence on the mechanical properties as well as on the gravimetric efficiency of the structure and is therefore investigated within this paper. Three series of samples were manufactured and tested: A) steel liners as reference, B) composite vessels with low fiber tension of 3 N, and C) vessels with high fiber tension of 80 N. The manufacturing process is discussed in this paper with special focus on the parameter of fiber tension and its related challenges. Burst tests with strain measurements and acoustic emission (AE) were conducted, and a statistical analysis of the results is presented. Additional numerical investigations on the structural behavior of the vessels and effect on the gravimetric efficiency are performed to support the experimental result. The investigations show that the increase in fiber tension induced compressive stress on the steel liner, leading to an increase in burst pressure and influence on AE. Furthermore, the fiber volume fraction (FVF) of the composite laminate increased due to increased fiber tension, resulting in higher mechanical properties and an improvement in gravimetric efficiency.

Multicriteria optimization as enabler for Sustainable Ceramic Matrix Composites

AbstractOver the past 40 years, development of Ceramic Matrix Composites (CMCs) has focused mainly on the improvement of material performance and optimization of cost‐efficient production routes. Recently, more fields of application have opened up for CMCs, in which environmental impacts are relevant. These impacts have barely been investigated so far but receive growing interest due to increasing awareness of the environmental consequences. Our innovative approach frames material properties in relation to environmental impacts (e.g., global warming potential in CO2 emission) by varying process parameters to balance optimum performance against environmental considerations. First, the process of wet filament winding has been investigated up to the Carbon Fiber Reinforced Plastic (CFRP) state by changing both the curing and tempering temperatures. During the production of CFRP plates, mass and energy flows were tracked in each step. Three point‐bending and interlaminar shear tests have been performed on the resulting samples to identify basic mechanical properties. The environmental impacts are determined by a cradle‐to‐gate Life Cycle Assessment (LCA), using the software SimaPro. The resulting tradeoffs between mechanical properties and environmental impacts show nonlinear behavior, thus revealing optimum points above which improved mechanical properties are associated with significantly higher CO2 emissions.

A nondestructive approach to predict buckling load of composite lattice-core sandwich conical shells based on vibration correlation technique

In this paper the vibration correlation technique (VCT) has been used as a nondestructive method for predicting the buckling load of the composite lattice-core sandwich conical shells. This technique is capable of predicting the buckling load of different structures without reaching the failure point through modal testing. The composite lattice-core sandwich conical shell has been fabricated using a filament winding process. To perform the expriment, the fundamental natural frequency of the specimen is measured under stepped axial compression loading. The procedure is followed up without actually reaching the instability point when the structure collapses and is no longer usable. A finite element model has also been built in ABAQUS in order to determine the correlation between natural frequency and applied compressive load. A comparison of the results indicated that the VCT has provided a reliable estimate of the buckling load of composite lattice-core sandwich conical shells, especially when the structure is loaded up to at least 66% of the experimental buckling load and accuracy of the VCT decreases when the maximum load is lower than 43% of the buckling load. Results also revealed that the linear fitted curve is unsuitable for the correlation between frequency of vibration and applied load in order to predict buckling load.

Offline Robot-Path-Planning and Process Simulation for the Structural Analysis of Coreless Wound Fibre-Polymer Composite Structures

In the coreless filament winding process (CFW) anchor points are wrapped with pre-impregnated fibre bundles (Towpregs) in a defined chronological order. With this process, fibre-polymer composite structures with a very high lightweight potential and very little material consumption can be created for different applications in the automotive, aeronautical, sports and architectural sector. The winding sequence and the fibre interaction thereby does have an influence on the final fibre architecture and thus on its structural behaviour. To take this into account a process chain for path planning and process simulation out of a design model is presented. To achieve flexible considerations of different design concepts a parameter-based method for the necessary path planning of the final three-dimensional fibre architecture is introduced. The approach is evaluated on different kinds of specimen.

External pressure buckling of composite sandwich conical shells with variable skin thickness

In this paper, an analytical model is developed to investigate the buckling analysis of the composite sandwich conical shell with variable skin thickness under lateral pressure loading. This problem involves composite shells, which are produced during the filament-winding process, where the skin thickness varies through the length of the shell. An effective smeared method is employed to reduce the reinforced lattice core into a layer. This is done by analyzing forces and moments on a unit cell. Therefore, equivalent stiffness parameters of reinforced lattice core are determined. By superimposing stiffness parameters due to the lattice core with those of the inner and outer skins, the equivalent stiffness of the sandwich panel will be obtained. Governing equations are established based on the first shear deformation theory. The power series method is used to extract the buckling load of the stiffened shell. To verify achieved results, a 3D finite element model is provided. Comparisons showed that the analytical solution is qualified enough to study the buckling behavior of the composite sandwich conical shell. Through this study, the effects of a set of important parameters like stiffener orientation angle, number of stiffeners, semi-vertex angle, and skin lamination are investigated.

Strength evaluation of CFRP structure of high pressure hydrogen tank based on mesoscale analysis

For designing with rigorous cost reduction and safety, high pressure hydrogen tanks manufactured from carbon fiber reinforced plastic (CFRP) of fuel cell vehicles, a method that can precisely predict the burst pressures of the tank is urgently needed. CFRP layers of tanks are formed with complicated mesostructured consisting of carbon fiber bundles and matrix resin using a filament winding process. A methodology that approaches by using cross shaped specimens to present fiber bundle conditions in CFRP layer of the tank is scrutinized. From the analysis and experiment with the specimen, it was found that strain rate dependency and tensile compression asymmetry of the resin have a great influence in addition to the fiber strength in the fiber direction on the CFRP fracture process. Burst pressures were predicted by CFRP mesoscale model with the load and boundary condition from macroscale analysis of conventional axisymmetric continuum model of the tank and validated through an actual tank burst test. As the results, we found the burst pressure of tank could be accurately predicted based on carbon fiber ruptures in the mesoscale model.

Non-contact techniques based on a vision system for the inspection of composite material components: analysis of the influence quantities

In this paper two different approaches, based on a vision system, are compared for the inspection of a carbon fibre piece, realized using a tow filament winding process. The defect of interest is the surface void percentage, which can strongly influence the mechanical and functional characteristics of the component. The approaches differ in the method of image processing: the first is based on a colour threshold setting; the second is based on a semantic segmentation algorithm. The comparison between the two techniques allows the identification of the main causes of variability, and the individuation of the advantages and limits of each one, which make them more or less suitable for use, depending on the specific application. The preliminary results show that both methods are promising for in field use, provided that the causes of variability are identified and kept under control.

On the buckling load estimation of grid-stiffened composite conical shells using vibration correlation technique

In this paper, the vibration correlation technique (VCT) has been used as a nondestructive method for predicting the buckling load of grid-stiffened composite conical shells. This technique is capable of predicting the buckling load of structures without reaching failure point through modal testing. The grid-stiffened composite conical shell has been fabricated using the filament winding process. To perform the experiment, the fundamental natural frequency of the specimen is measured under stepped axial compression loading. The procedure is followed up without actually reaching the instability point when the structure collapses and is no longer usable. A finite element model has been built using ABAQUS software considering the effect of geometric imperfection in order to determine the correlation between natural frequency and applied compressive load. A comparison of the experimental and numerical approaches indicated that the difference between numerical buckling loads and those obtained via the VCT is negligible. Moreover, the VCT has provided a reliable estimate of the buckling load, especially when the maximum applied load is greater than 67% of the experimental buckling load.

Hybrid Thermoset-Thermoplastic Structures: An in-depth study on plasma pretreated continuous fiber-reinforced epoxy specimens

Hybrid thermoset-thermoplastic structures can be manufactured by using a 3d robot-based filament winding process, low-pressure plasma and thermoplastic injection molding. This newly hybrid concept is only possible, when a strong interface is created between the two different polymer systems. Low-pressure plasma has the ability to expose the carbon fibers of a cured continuous carbon fiber reinforced epoxy (CFRP) structure so that a direct load transfer between the two polymers via the continuous fibers is possible. It also improves the bonding of short glass fiber reinforced polyamide (PA6GF30) to these carbon fiber epoxy structures. It is possible to create load path optimized structural hybrid components in a highly automated manner with this discovery. Therefore, different low-pressure plasma processes, plasma gases, plasma durations and a robot-based specimen production are investigated.

Investigation of the Fabrication Suitability, Structural Performance, and Sustainability of Natural Fibers in Coreless Filament Winding.

Coreless filament winding is an emerging fabrication technology in the field of building construction with the potential to significantly decrease construction material consumption, while being fully automatable. Therefore, this technology could offer a solution to the increasing worldwide demand for building floor space in the next decades by optimizing and reducing the material usage. Current research focuses mainly on the design and engineering aspects while using carbon and glass fibers with epoxy resin; however, in order to move towards more sustainable structures, other fiber and resin material systems should also be assessed. This study integrates a selection of potential alternative fibers into the coreless filament winding process by adapting the fabrication equipment and process. A bio-based epoxy resin was introduced and compared to a conventional petroleum-based one. Generic coreless wound components were created for evaluating the fabrication suitability of selected alternative fibers. Four-point bending tests were performed for assessing the structural performance in relation to the sustainability of twelve alternative fibers and two resins. In this study, embodied energy and global warming potential from the literature were used as life-cycle assessment indexes to compare the material systems. Among the investigated fibers, flax showed the highest potential while bio-based resins are advisable at low fiber volume ratios.

Estimating the burst pressure of a filament wound composite pressure vessel using two-scale and multi-scale analyses

The influence of inescapable imperfections associated with fiber arrangement in the filament winding process on the burst pressure of a composite vessel is analyzed. Firstly, the influence of fiber packing, fiber spacing and fiber contiguity is analyzed through a two-scale analysis. Mechanical properties of the layers are estimated considering aforementioned parameters at the scale of micro and the burst pressure is estimated at the scale of macro. As the second approach, fiber-bundle crossovers and undulation arisen from filament winding process are also considered at the scale of meso. Thus, a multi-scale modeling is performed capturing micro, meso and macro scales.