Fiber Bed Research Articles

Series solution and its extension for the nonlinear flow response of soft hair beds

In nature and engineering applications, flexible fiber beds covering biological surfaces can play a role in reducing resistance. These fibers deform under the action of fluids, and this deformation affects the fluid flow state, forming a complex fluid–solid interaction phenomenon. To quantitatively analyze these issues, the physical model is simplified. We focus on the deformation of a soft hair bed caused by Stokes flow. Additionally, we study the deformation of a single hair under Stokes flow in greater detail. The deformation problem of an elastic single fiber in a channel caused by Stokes flow can be described by a nonlinear integral equation. We have obtained a new series solution, which has been compared with the previous perturbation method to verify the accuracy and effectiveness of the series solution. Meanwhile, we have further provided an extended form of flexible fiber deformation through experimental fitting. This fluid–solid interaction problem involves multiple fields and is very important in many natural and engineering systems. The research in this paper can not only help us better understand complex phenomena in nature but also delve into the interaction mechanism between fluids and solids, providing a theoretical basis for future scientific research and engineering applications.

Experimental Investigation on Durability Properties of Slurry Infiltrated Fiber Concrete

Slurry infiltrated fibrous concrete (SIFCON) can be considered as a special and advanced type of steel fiber reinforced concrete composite. SIFCON is produced by infiltrating rich flow able cement slurry into the bed of preplaced fibers in the mold. In this paper, an attempt has been made to investigate the durability study of SIFCON. An ordinary Portland cement is used with fiber contents of (5%, 7.5%, 10%, and 12%). This study also presents the effect of incorporating Metakaolin (MK) on the mechanical and durability properties of SIFCON for a constant water/cement ratio of 0.5. The physical properties include the specific gravity, density, fineness modulus, water absorption, consistency. The above properties are studied for materials used like cement, fly ash, coarse aggregate, ceramic, sand and laterite. Mechanical properties of the hardened concrete such as compressive strength, tensile strength, flexural strength, and durability properties like water absorption, sorptivity, acid test, marine environment are tested and the values are validated. Metakaolin is a waste/non-conventional material which can be utilized beneficially in the construction industry. From the literature survey, Metakaolin inclusion increases the compressive, tensile, flexural and bend strength and modulus of elasticity of mortar considerably; however, the workability is slightly compromised.

Saturated transverse permeability of unidirectional rovings for pultrusion: The effect of microstructural evolution through compaction

AbstractThe transverse permeability of roving/tow‐based fiber reinforcement is of great importance for accurate flow modeling in the pultrusion process. This study proposes an experimental approach to characterize the roving‐based fiber beds' permeability under different compaction conditions. The experimental permeability results of thick roving‐based preforms were reported and compared with the permeability values of roving‐based preforms in the literature. A representative preform was infused under vacuum conditions. Its thickness was varied to replicate the different compaction values observed in permeability tests. Micrographs were then collected from it and analyzed to highlight the microscale transformations caused by processing/compaction on the fiber arrangement. The analysis revealed that compaction resulted in the reorganization of filaments along the direction of the applied compaction. Overall, the uniformity of the spatial filament distribution, i.e., the homogeneity within the fibrous domain, increased with increasing compaction. Furthermore, the microstructural analysis demonstrated transverse anisotropy within the tested domains, indicating that the obtained permeability results represented an upper boundary. In addition to the experimental analyses, various transverse permeability models, which were developed based on recently introduced statistical descriptors of fiber distribution, were evaluated by using the statistical descriptors extracted from the analyzed cross‐sections. Among these models, the one correlating the second neighbor fiber distance with apparent permeability exhibited good agreement with the experimental results.Highlights Transverse permeability measurement of a roving‐based reinforcement was presented. The influence of compaction on the microstructure was investigated at the filament level. Filament distribution in a pultruded profile was analyzed by using statistical descriptors. The results of the experiments and the models in the literature were compared. The correlation between microstructural features and apparent permeability was discussed.

Slurry Infiltrated Fiber Concrete Properties: A Review

“Slurry infiltrated fibrous concrete” refers to a contemporary, high performing fiber-reinforced concrete and infiltrated with a specially designed fiber bed, cement-based slurry. The material has excellent mechanical properties along with high durability and ductility. The SIFCON Laboratory’s research revealed SIFCON to be a unique building material with improved abilities to absorb energy and resist impact, as well as greater ductility and strength. With all these qualities, SIFCON can repair and fortify both reinforced and unreinforced concrete structures. Ductility is currently one of concrete’s most critical characteristics. The issue of brittleness with concrete has been solved by utilizing a high volume of fibers instead of coarse aggregate, which provides stress-resistant properties and increases the ductility of the structural component. However, due to the placement and mixing challenges because of the high volume of fibers’ interlocking action, there is a necessity to design unique production techniques. Since SIFCON compounds are a novel trend in the fields of areas of civil engineering that have a catalytic effect, it is necessary to highlight the few studies that included it so this review paper discusses and presents the behavior of SIFCON under various external loads. The focus is on the effects of the SIFCON mortar type—which substitutes silica fume and/or fly ash for cement—and fiber type—which uses hooked end fiber and micro steel fiber— are the main topic of discussion. The mechanical characteristics and optimal percentages are also reviewed. All previous studies are noted and summaries are made in comprehensive tables, which display the studied parameters and SIFCON mortar mix ratios. In addition to indicating research gaps, for example, future work in this field needs to focus on developing a detailed analytical model that requires the ability to calculate these factors. A better understanding of the SIFCON’s features can serve as a theoretical foundation for future research projects and engineering applications for creating concrete materials for the construction industry.

A numerical investigation on segregation in gas-fluidized beds of short, flexible fibers

Numerical simulations of gas-fluidized beds of short, flexible fibers are performed using a coupled approach of discrete element method (DEM) and computational fluid dynamics (CFD), and segregation of bidisperse fibers is investigated. A gas critical velocity exists for achieving the maximum degree of segregation, characterized by a segregation index SI. and it is about 1.5 times minimum fluidization velocity for present particulate systems. The segregation is determined by two mechanisms: air entrainment mechanism, attributed to the difference in air effects on fiber motion, and sifting mechanism, due to the difference in fiber sizes. Smaller and lighter fibers tend to move to upper region of a fiber bed due to the air entrainment mechanism, while the smaller fibers more likely migrate to lower region due to the sifting mechanism. The interlinked effects of the two mechanisms are analyzed, and a phase diagram to determine SI is consequently created based on an air-effect ratio and a fiber diameter ratio. When the air-effect ratio is higher than 1.3, significant segregation occurs due to the enhancement from both the mechanisms; while when the air-effect ratio is below 0.8, weaker segregation is observed as the air entrainment and sifting effects counterbalance each other.

Effect of gaps on preform and laminate made by automated dry fiber placement and resin infusion

Automated Dry Fiber Placement (ADFP) provides ease in fiber steering compared to the automated placement of prepregs and a higher material deposition rate than manual hand layup. Vacuum Assisted Resin Infusion (VARI) can be used to infuse the resin into the bed of dry fibers to make the composite. The resin flow rate depends on the permeability of the dry fiber preform, which is dependent on the preform fiber volume fraction. Automated Fiber Placement (AFP) allows the capacity to control the fiber volume fraction in terms of gaps between the tows. So, reducing the fiber volume fraction of preforms by introducing gaps into the preform pattern can increase the permeability. On the other hand, introducing gaps in layup results in a drop in the mechanical properties of the laminate (such as compressive modulus and strength). An optimum gap size may provide a significant gain in permeability with minimum loss in compressive properties. This paper investigates the effect of the gap size in the preform pattern on the preform out-of-plane permeability and compressive properties of the laminate. The out-of-plane permeability of three specimens from preforms, with varying gap sizes (0mm, 0.4mm, and 0.8mm) in all layers were measured. Also, the compressive properties of five coupons made from laminates, with and without gap sizes (0mm, 0.4mm, and 0.8mm) were determined. It was shown that introducing gaps with 0.4 mm size between fiber tapes in the layup can increase the out-of-plane permeability 17 times and reduce the compressive strength and modulus by 6 % and 7.2 %, respectively.

Numerical simulation of convective heat transfer in packed bed using open-source computational fluid dynamics

The shape and stacking method of the packing elements will affect the overall performance of the packed bed structure. In this study, the convection heat transfer in packed beds was simulated using the customized OpenFOAM “porousFoam_pimple” solver, which could provide the direction for the actual design and optimization of packed bed. Blender was used to generate the packed beds of spheres and fibers. Moreover, the influence of packed bed geometry on the convective heat transfer performance was investigated. The average pressure gradient and comprehensive heat transfer efficiency vary greatly with the parameters, such as fiber diameter, fiber axial, inlet velocity angle, and fiber interleaving degree. The customized “porousFoam_pimple” solver can be used for the numerical simulation of the convective heat transfer in packed beds with particles of different shapes under different operating conditions, providing a reliable and practical tool for the design and optimization of packed beds.

Impact of a transverse magnetic field on flow through porous cylindrical fiber beds with permeability enhancement analysis

Flow of a viscous, incompressible and electrically conducting fluid through an aggregation of porous cylindrical fibrous beds in an axisymmetric direction has been considered. The effect of a uniform magnetic field in the transverse direction to the flow on the overall bed permeability (OBP) has been studied via an effective medium approximation. At the interfaces, continuity of velocity and stress components has been employed. In order to gain some physical insight into the flow pattern, the impact of different parameters governing the flow such as porosity, internal permeability, and the magnetic parameter on the OBP and velocity field has been analyzed analytically as well graphically. The expressions of skin friction at the inner and outer boundaries of the envelope are also derived and their behavior with respect to flow parameters are analyzed through graphs. Results show that the porous core subjected to a normal magnetic field increases the OBP, in the sense that it decreases the filtration time. Thus, the presence of magnetic field gives the flexibility to maintain the OBP of the present model unaffected even when its porosity decreased due to any possible contamination. Under special cases, when the internal permeability tends to zero (solid core), and in the absence of the magnetic field, obtained results validate with already published results.

Intensify staple fibre drying by optimizing air distribution in multistage convective dryer using CFD

A non-uniform air distribution in the conveyor dryer contributes towards an uneven drying of material. In case of cellulosic fibre drying, portion of fibre bed, which is exposed to high air flow rate, dries faster compared to portion receiving lower air flow at the same temperature. Therefore, non-uniform moisture distribution is observed across the fibre bed. Along with on-field measurement, 3D Computational Fluid Dynamics (CFD) modeling was carried out to study air profile inside the convective dryer (capacity ∼x223C20 TPD). Validated model was used to design an optimum air distribution sieve to enhance the air uniformity which leads to uniform moisture across the dryer width. Five different air distribution sieves (Design – 1–5) were designed, and air velocity distribution were compared. Air distribution sieve with overall 17% opening (Design-4) shows 64% higher air uniformity from the base case which enhances production of premium grade (moisture range: 10.5–11.5%) fibres by 5% at the commercial scale. The robustness of the adopted design also shows its scalability from small (∼x223C20 TPD) to large scale dryer (capacity >100 TPD).

A reusable neural network pipeline for unidirectional fiber segmentation

Fiber-reinforced ceramic-matrix composites are advanced, temperature resistant materials with applications in aerospace engineering. Their analysis involves the detection and separation of fibers, embedded in a fiber bed, from an imaged sample. Currently, this is mostly done using semi-supervised techniques. Here, we present an open, automated computational pipeline to detect fibers from a tomographically reconstructed X-ray volume. We apply our pipeline to a non-trivial dataset by Larson et al. To separate the fibers in these samples, we tested four different architectures of convolutional neural networks. When comparing our neural network approach to a semi-supervised one, we obtained Dice and Matthews coefficients reaching up to 98%, showing that these automated approaches can match human-supervised methods, in some cases separating fibers that human-curated algorithms could not find. The software written for this project is open source, released under a permissive license, and can be freely adapted and re-used in other domains.

The effect of fibre morphology on packing phenomena and bed properties in coalescers

In this study, fibre morphology of waste materials and its effect on packing phenomena and bed properties were investigated. Nine waste materials were used in bed coalescers. By scanning electron microscopy, it was determined that surfaces of all fibres were smooth, while cross-section differed from circular, rectangular to irregular. The fibres with circular cross-sections had diameters in the range of 12?0.8 to 40?4 ?m, while the fibres of polypropylene bags and sponges appeared as strips with the widths of 452?11 and 1001?14 ?m, respectively. It was also noticed that polyurethane fibres were connected forming a sponge-like structure, while polyethylene terephthalate fibres were interconnected at some points. In this work, experimental dependence of bed porosity on bed permeability was established for all investigated materials, which allows forming a fibre bed with desired permeability. The exception was the bed formed of fibres of polypropylene bags, which had the largest dimensions and yielded a different porosity-permeability dependence.

Experimental Research of Fibrous Materials for Two-Stage Filtration of the Intake Air of Internal Combustion Engines.

Pollutant properties in intake air to internal combustion engines were analyzed. Mineral dust particles’ influence on accelerated engine components’ wear was discussed. Dust concentration values in the air under various operating conditions in trucks and special vehicles were presented. The idea and necessity for using two-stage filters, operating in a “multi-cyclone–porous partition” system for vehicles operated in dusty air conditions, are presented. Information from the literature information has been presented, showing that impurities in small grain sizes reduce fiber bed absorbency. It has been shown that such a phenomenon occurs during filter material operation, located directly behind the inertial filter (multi-cyclone), which off-road vehicles are equipped with. It results in a greater pressure drop intensity increase and a shorter proper filter operation period. It has been shown that filter material selection for the motor vehicle air filter requires knowledge of the mass of stopped dust per filtration unit area (dust absorption coefficient km) determined for a given permissible resistance value Δpfdop. It has been shown that there is no information on absorption coefficient values for filter materials operating in a two-stage “multi-cyclone–porous partition” separation system. Original methodology and conditions for determining dust absorption coefficient (km) of a separation partition, operating under the conditions of two-stage filtration, were presented. The following characteristics were tested: separation efficiency, filtration performance, and pressure drop characteristics of three different filtration partitions. These were A (cellulose), B (cellulose and polyester), and C (cellulose, polyester, and nanofibers layer), working individually and in a two-stage system—behind the cyclone. Granulometric dust composition dosed into the cyclone and cyclone downstream was determined. During tests, conditions corresponding to air filter’s actual operating conditions, including separation speed and dust concentration in the air, were maintained. For the pressure drop values, the dust absorption coefficient (km) values of three different filtration partitions (A, B, and C), working individually and in a two-stage system—behind the cyclone—were determined experimentally.

Filtering efficiency model that includes the statistical randomness of non-woven fiber layers in facemasks.

Facemasks have become important tools to fight virus spread during the recent COVID-19 pandemic, but their effectiveness is still under debate. We present a computational model to predict the filtering efficiency of an N95-facemask, consisting of three non-woven fiber layers with different particle capturing mechanisms. Parameters such as fiber layer thickness, diameter distribution, and packing density are used to construct two-dimensional cross-sectional geometries. An essential and novel element is that the polydisperse fibers are positioned randomly within a simulation domain, and that the simulation is repeated with different random configurations. This strategy is thought to give a more realistic view of practical facemasks compared to existing analytical models that mostly assume homogeneous fiber beds of monodisperse fibers. The incompressible Navier-Stokes and continuity equations are used to solve the velocity field for various droplet-laden air inflow velocities. Droplet diameters are ranging from 10nm to 1.0µm, which covers the size range from the SARS-CoV-2 virus to the large virus-laden airborne droplets. Air inflow velocities varying between 0.1m·s-1 to 10m·s-1 are considered, which are typically encountered during expiratory events like breathing, talking, and coughing. The presented model elucidates the different capturing efficiencies (i.e., mechanical and electrostatic filtering) of droplets as a function of their diameter and air inflow velocity. Simulation results are compared to analytical models and particularly compare well with experimental results from literature. Our numerical approach will be helpful in finding new directions for anti-viral facemask optimization.

Role of resin percolation in gap filling mechanisms during the thin ply thermosetting automated tape placement process

During the automated tape placement process, gaps between adjacent tapes are created due to the limitation of machine accuracy, especially at higher speeds. These gaps are undesirable as they cause porosity, thickness variation, and fiber waviness, introducing defects in the composite part. Applying pressure and temperature to part can assist in partially or completely filling these gaps. For thermosetting resins, such processing is usually required for the material to reach complete consolidation. Modeling the tape deformation as squeeze flow of fibrous suspension in the liquid matrix is usually deployed to determine gap filling and tape deformation. However, existence of resin rich zones in the micrographs of fabricated parts suggests that there may be a second flow process involved which is the percolation of matrix through the fiber bed into the remaining empty space of the gaps. This paper extends the previous work that modeled the cross-ply deformation and squeeze flow as the primary mechanisms in the gap filling process during consolidation of thermosetting composites. Based on our experimental results, this work adds the percolation flow to the model to predict (1) the spread of fiber/matrix suspension into the gap, (2) the resin percolation out of the fiber bed into the gap and (3) the deformation of the cross (bridging) ply or plies. The governing equations are formulated, and scaling analysis is performed to estimate the effect of tape thickness on percolation flow confirming that this mechanism is more significant when thin tapes are employed. Fixed mesh numerical scheme is used to evaluate the deformation and flow progression of both the resin percolation flow and the squeeze flow of fiber/resin suspension during the consolidation process. A parametric study is conducted to evaluate the effect of model parameters. Finally, the predicted percolated resin flow along with squeeze flow advancement is compared with experimental results.

Chemisorption of basic fuchsine in packed beds of dialdehyde cellulose fibres

The discharge of textile dyes in water systems, due to poor binding to fabrics, is a major health and environmental concern. The majority of synthetic dyes used in textile are hazardous and carcinogenic. Despite efforts in addressing challenges associated with covalent binding of dyes to fibers and effluent filtration, there has been no promising green solution based on green materials and chemistry. Here, we demonstrate that dialdehyde cellulose (DAC) engineered through the chemical functionalization of cellulose fibres provides great functionality for Schiff base dye conjugation. Breakthrough curves (BTCs) of basic fuchsine in packed beds of DAC fibers were fitted to a Langmuir model and pseudo-first order kinetics. DAC fibers with an aldehyde density of 10.8 mmol g-1 had an adsorption capacity, adsorption and desorption rates of 204 mg g-1, 0.05 min-1 and 9.0 × 10-5 min-1, respectively. For cellulose fibers, used as a control, these values are 61 mg g-1, 0.15 min-1 and 2.6 × 10-3 min-1, respectively. It is shown that all dye is chemisorbed on DAC fibres, after initial physisorption and ion-exchange. Addition of 1 M NaCl to the dye solution resulted in coagulation of the dye and the removal capacity through filtration increased to 489 mg g-1, a process ideal for dye recovery or water purification.

Effects of automated fiber placement defects on high strain rate compressive response in advanced thermosetting composites

The effects of fiber tow gaps, overlaps, and folds on the compressive strength of a fiber-placed composite laminate under dynamic loading conditions are investigated in this work. These layup defects were placed in the 0° fiber direction within a 24-ply quasi-isotropic laminate with a [45/0/–45/90]3S stacking sequence. Different locations of the defect were considered, namely near the bottom (in the 2nd ply), middle (10th ply) and top (23rd ply) of the laminate. High-strain rate compression experiments were conducted on composite that are pristine and with embedded defects using a split Hopkinson pressure bar (SHPB). The results were used to determine the strength knockdown due to the local changes in ply morphology because of fiber bed compaction in the presence of a layup defect. The experimental results revealed the anisotropy of in-plane strength coinciding with the deposited defect orientation. No significant variations in the residual strength were observed regarding the location of the defect (i.e., bottom, middle, or top) within the laminate. A morphological analysis based on microtomography of the cured defects indicates that the sources of the strength knockdown are due to the 0° ply drop-off, fiber misalignment in the adjacent 90° and 45° degree plies and the resin-rich region formed at the corner of the tapered 0° ply, between +45° and –45° laminas. The present study indicates the increased role of local morphological ply variations on the strength of composites under high-strain rate loading conditions, which should be considered during composite design.

A mixed lubrication model for inter-ply friction behaviour of uncured fabric prepregs

Inter-ply friction plays a dominant role in the generation of fiber-path defects (e.g. wrinkling) in the consolidation stage of composites manufacturing. In particular, for most thermoset prepregs, the mixed lubrication regime can be a dominating factor controlling the frictional response over the range of the processing window. This article presents a generic computational modelling approach to describe the mixed lubrication regime by combining an inverse hydrodynamic‐lubrication (IHL) theory and an asperity contact model. A homogenized resin film thickness can be derived from this analysis, rather than postulating it as in earlier conventional models. Thermal effects and fiber bed compliance in the inter-layer contact area as well as the influence of the resin rheology are assessed, finally enabling the model to be verified against inter-ply friction experiments under a wide range of processing conditions. The model has been exemplified on a fabric carbon/epoxy prepreg.

Phase segmentation of uncured prepreg X-Ray CT micrographs

This paper explores methods to investigate voids and dry fibre areas in pre-impregnated aligned carbon fibre reinforced epoxy lay-ups. A deep learning segmentation approach was compared to conventional thresholding techniques to characterise the interlaminar voids (entrapped air) and dry areas (unsaturated fibre bed) phases obtained by micro-CT scanning of samples from uncured laminates. The performance of both approaches was quantitatively assessed in three regions of interest having different levels of porosity, ranging from a low 1% to a high 25%. Deep learning consistently outperformed thresholding in the segmentation of both interlaminar voidage and dry areas. Furthermore, deep learning improved the ability to detect small voids and was able to accurately segment voids in volumes with less than 2% voidage, whereas thresholding techniques fail in this task. Finally, the application of deep learning to the segmentation of dry areas in micro-CT scans provided sharper results than thresholding, without needing filtering.

A Mechanistic Model for Wellbore Cleanout in Horizontal and Inclined Wells

Summary The accumulation of rock cuttings, proppant, and other solid debris in the wellbore caused by inadequate cleanout remarkably impedes field operations. The cuttings removal process becomes a more challenging task as the coiled-tubing techniques are used during drilling and fracturing operations. This article presents a new hole cleaning model, which calculates the critical transport velocity (CTV) in conventional and fibrous water-based fluids. The study is aimed to establish an accurate mechanistic model for optimizing wellbore cleanout in horizontal and inclined wells. The new CTV model is established to predict the initiation of bed particle movement during cleanout operations. The model is formulated considering the impact of fiber using a special drag coefficient (i.e., fiber drag coefficient), which represents the mechanical and hydrodynamic actions of suspended fiber particles and their network. The dominant forces acting on a single bed particle are considered to develop the model. Furthermore, to enhance the precision of the model, recently developed hydraulic correlations are used to compute the average bed shear stress, which is required to determine the CTV. In horizontal and highly deviated wells, the wellbore geometry is often eccentric, resulting in the formation of flow stagnant zones that are difficult to clean. The bed shear stress in these zones is sensitive to the bed thickness. The existing wellbore cleanout models do not account for the variation in bed shear stress. Thus, their accuracy is limited when stagnant zones are formed. The new model addresses this problem by incorporating hydraulic correlations to account for bed shear stress variation with bed height. The accuracy of the new model is validated with published measurements and compared with the precision of an existing model. The use of fiber drag and bed shear stress correlations has improved model accuracy and aided in capturing the contribution of fiber in improving wellbore cleanout. As a result, for fibrous and conventional water-based fluids, the predictions of the new model have demonstrated good agreement with experimental measurements and provided better predictions than the existing model. Model predictions show a noticeable reduction in fluid circulation rate caused by the addition of a small quantity of fiber (0.04% w/w) in the fluid. In addition, results show that the existing model overpredicts the cleaning performance of both conventional and fibrous water-based muds.

On the physical relevance of power law-based equations to describe the compaction behaviour of resin infused fibrous materials

The mechanical performance of structural parts (e.g. a 20 m+ aircraft wing) made from pre-impregnated (prepreg) fibre reinforced polymers (FRP) are intimately linked to the material's meso‑scale (sub-mm length) and micro-scale (μm length), which in turns depends upon the way the fibre mat impregnated with resin has been processed. Particularly important is the way the resin flows through the fibre bed, as that influences the level of porosity and the orientation of the fibres in the final part by controlling the stack's change of thickness during manufacture. In this paper, the applicability of a recently proposed phenomenological model, able to predict the thickness evolution of a wide class of prepreg stacks under processing conditions, is investigated. One of the model's main advantages is that, unlike other flow-compaction models, it can capture the transition between squeezing and bleeding flow. The model's significance for a variety of reinforcements (i.e. UD carbon, UD glass and carbon fibre plain weave) and resin systems (i.e. first and second generation of toughened thermoset and thermoplastic resins) is demonstrated. A new physics-based interpretation of the material parameters is proposed. This gives rise to an analytical expression relating the thickness evolution with time to the applied temperature and pressure cycles, the viscosity of the resin, and meso‑ and micro- geometrical characteristics of the reinforcements. The contribution paves the way towards a better understanding and control of the variability and increased digitalisation of the design and manufacturing processes of composite structures.