Emerging technologies in filament winding: Materials, multifunctionality and embedded systems - A426

 

Emerging technologies in filament winding: Materials, multifunctionality and embedded systems
Document Type	Article
Document Identifier	426
Tags	Deposition
Prerequisites	The factory Factory cells (where and how) Material deposition Filament winding

Introduction

Filament winding (FW) is evolving rapidly due to new material systems and digital manufacturing concepts. This article introduces emerging technologies reshaping FW, from thermoplastic towpregs and multifunctional matrices to embedded sensors and adaptive control, highlighting opportunities for innovation across Canadian industry.

Significance

The first section reviews advanced material systems, including thermoplastic tapes having PEEK (polyether ether ketone), PPS (polyphenylene sulfide), and PP (polypropylene) matrices and high-temperature thermoset towpregs (bismaleimide (BMI), cyanate ester, etc.) .

It describes processing challenges such as in-situ consolidation and local heating requirements . Next, multifunctional composites are discussed, featuring resin systems with electrical conductivity, self-sensing capability, or barrier layers for fluid containment . The integration of embedded structures (fiber-optic sensors, strain gauges, or RFID tags) is presented as a route toward smart filament-wound components capable of structural health monitoring . Finally, the article highlights digital and model-based manufacturing, emphasizing feedback-controlled winding paths and virtual simulation .

Scope

Readers understand how to evaluate and potentially adopt new FW technologies for high-value applications. The content encourages collaboration between research institutions and industry to pilot multifunctional and data-enabled composite systems.

Advanced Material Systems for Filament Winding

Advanced material systems for FW emphasize thermoplastic composites and high-temperature thermoset systems due to their performance, durability, and manufacturing advantages . Thermoplastic tapes based on matrices such as PEEK, PPS, and PP are highlighted for their high toughness, damage tolerance, and recyclability . These materials enable rapid processing cycles because they do not rely on chemical curing reactions, instead consolidating through heating and cooling. Thermoplastic tapes are well suited for pressure vessels, pipes, and structural components requiring high impact resistance and fatigue durability. PEEK- and PPS-based systems are particularly suitable for applications demanding elevated temperature resistance and chemical stability. These materials retain mechanical integrity under aggressive service environments and are compatible with automated manufacturing routes such as FW and automated fiber placement . PP-based thermoplastic composites may be considered cost-effective alternatives for moderate-performance applications, offering low density and corrosion resistance while still benefiting from thermoplastic processing advantages.

In contrast, high-temperature thermoset towpregs, particularly those based on BMI, cyanate ester, and related resin systems, are reviewed as established solutions for demanding aerospace and pressure-containment applications . These towpregs combine continuous fiber reinforcement with solid or semi-solid resin, allowing controlled impregnation and tack during winding. Notably, some materials such as BMI towpreg feature a matrix phase that can be liquified by heating, which provides opportunities to combine the advantages of towpreg winding and conventional wet winding when using heated mandrel systems or external heating sources such infrared heaters. Parts made from these composite systems offer high thermal stability, low moisture uptake, and superior dimensional stability compared with conventional epoxy systems, making them suitable for thick-walled or load-critical filament-wound structures.

Processing Challenges and In-Situ Consolidation

Despite the advantages of advanced material systems, significant processing challenges exist, particularly for thermoplastic FW. In-situ consolidation is identified as a central technical hurdle, requiring sufficient heat and pressure during winding to achieve intimate contact between adjacent layers and eliminate voids . Unlike thermoset systems, thermoplastics demand localized heating above the matrix melting temperature at the point of deposition, followed by controlled cooling to ensure proper crystallization and interlaminar bonding. The literature describes various localized heating strategies, including laser, infrared, hot-gas, and resistive heating systems, each with distinct advantages and limitations . Laser-assisted FW offers precise energy delivery and rapid heating rates but requires careful control to avoid thermal degradation or uneven consolidation. Infrared and hot-gas heating systems are noted for their broader heating zones, which can be beneficial for thicker sections but may reduce process precision.

In contrast, high-temperature thermoset towpregs, particularly those based on BMI, cyanate ester, and related resin systems, are reviewed as established solutions for demanding aerospace and pressure-containment applications . These towpregs combine continuous fiber reinforcement with solid or semi-solid resin, allowing controlled impregnation and tack during winding. Notably, some materials, such as BMI towpregs, feature a matrix phase that can be liquefied by heating (i.e., the resin is ‘frozen’ at room temperature), which provides opportunities to combine the advantages of towpreg winding and conventional wet winding when using heated mandrel systems or external heating sources such as infrared heaters. Parts made from these composite systems offer high thermal stability, low moisture uptake, and superior dimensional stability compared with conventional epoxy systems, making them suitable for thick-walled or load-critical filament-wound structures.

Multifunctional Composite Concepts

Beyond structural performance, filament-wound composites are increasingly engineered to deliver multifunctional capabilities. Multifunctional glass fiber/epoxy composite tubes demonstrate how FW production lines can be modified to incorporate additional functionalities without disrupting the primary load-bearing role of the structure . These multifunctional systems integrate electrical conductivity, sensing capability, and barrier performance directly into the composite architecture. Electrically conductive pathways are achieved through the integration of conductive phases (e.g., particulate carbon fillers) within the resin system or through strategically placed functional layers during winding . These features enable damage detection, strain monitoring, or electromagnetic shielding while maintaining structural integrity. However, these multifunctional designs require careful coordination of winding sequence, material placement, and curing conditions to ensure compatibility between structural and functional layers.

On the other hand, barrier layers can be considered as critical elements for fluid containment applications, particularly in pipes and pressure vessels exposed to aggressive media . These layers are integrated during FW to limit permeation, protect reinforcement fibers, and extend service life. The referenced work demonstrates that FW allows precise placement of barrier materials, enabling tailored performance across the wall thickness. These cross-scale manufacturing approaches can increase scalability and industrial relevance, showing that multifunctional features can be embedded using modified yet practical FW processes .

Embedded Structures and Smart Filament-Wound Components

The integration of embedded sensing elements (i.e., fiber optic sensors) can be considered as a key pathway toward smart filament-wound structures capable of real-time structural health monitoring . These sensors enable continuous monitoring of strain, temperature, and damage evolution throughout the service life of the structure. Fiber optic sensors are particularly emphasized due to their small size, immunity to electromagnetic interference, and compatibility with composite processing environments . Their integration within filament-wound laminates allows internal state measurements that are not accessible through surface-mounted sensors. Sensor placement must be carefully coordinated with winding patterns to avoid fiber and sensor damage and signal degradation.

In addition to fiber optic sensors, embedded strain gauges and identification elements such as RFID tags might be considered as complementary technologies for smart composite systems . These embedded structures support condition-based maintenance strategies and enhance the reliability of critical components such as propellant tanks and pressure vessels. Embedding sensors during FW does not inherently compromise structural performance when properly designed, reinforcing the feasibility of smart composite manufacturing at the component scale.

Digital and Model-Based Manufacturing in Filament Winding

In-situ monitoring techniques using embedded or surface-mounted sensors are used as tools for capturing real-time process and structural response data . These systems enable monitoring of temperature, pressure, strain, and fatigue damage during fabrication and service, providing feedback for both manufacturing optimization and operational safety. In contrast, machine performance characterization and experimental assessment of multi-axis FW systems highlight the importance of precise kinematic control and repeatability . Machine accuracy influences fiber placement, winding angle fidelity, and overall component quality. Such assessments support the development of digital twins and predictive models for FW processes.

Robotic FW can be considered as a transformative approach for manufacturing complex-shaped structural parts . By decoupling fiber placement from traditional mandrel-based constraints, robotic systems enable variable-angle winding, highly non-axisymmetric geometries, and enhanced design freedom. Virtual simulation and offline programming are essential for collision avoidance, path optimization, and defect minimization in robotic FW.

Digital and model-based manufacturing approaches underscore the transition toward feedback-controlled, digitally enabled FW systems. Virtual simulation, sensor-driven monitoring, and adaptive control strategies are then considered as enablers for improving quality, reducing waste, and expanding the design space of filament-wound composite structures .

References

A single unit of fibre reinforcement that cannot be separated further without breaking it. It often has a circular cross section that is formed by the dies used to create it or its precursor material. Many filaments are manufactured in parallel to produce a strand or tow. The number of filaments in a strand or tow is often references by how many thousands of filaments comprise the tow. e.g. an 18k tow is made up of ~18000 filaments.

A class of polymer, some common examples include polypropylene and polyethylene.

They soften and melt upon heating (i.e. potentially recyclable), high viscosity when melted, therefore difficult to saturate fibres. Usually needs a lot of pressure and heat to process.

Thermosets are a class of polymer that undergo polymerization and crosslinking during curing with the aid of a hardening agent and heating or promoter. Initially they behave like a viscous fluid. During curing, they change from viscous fluid to rubbery gel (viscoelastic material) and finally glassy solid.

If heated after curing, initially they become soft and rubbery at high temperatures. If further heated, they do not melt but decompose (burn)

Comes in two parts: part A (resin) and B (hardener). When mixed, curing reaction starts and is not reversible.

Examples include epoxy or polyester.

For polymer matrix composites (PMCs), resin refers to the matrix; the continuous material phase that binds the reinforcement together, maintains shape, and transfers load. Resins are divided into two main groups: thermosets and thermoplastics.

Engineered materials (designed to have specific properties) made from two or more constituent materials with different physical or chemical properties. The constituents remain separate and distinct on a macroscopic level within the finished structure.

The continuous material phase that binds the reinforcement together, maintains shape, transfers load, protects the reinforcement from environment and damage, and provides the composite support in compression.

Desirable characteristics:

• Moisture/chemical resistance
• Low density
• Processability

The use of multiphysics models to predict the outcome of real-world scenarios. May be analytical (closed form, "hand calculations") or computational (implementation on computers is required due to the large number of calculations involved. e.g. finite element method, finite difference method)

Most often in composite materials engineering, simulation refers to either:

• Process simulation (predicting manufacturing outcomes, or the inverse problem of predicting manufacturing parameters to achieve a desired outcome), or
• Performance simulation (predicting the stiffness/strength/suitability of a structure, or the inverse problem of the material properties and dimensional requirements to achieve a desired stiffness/strength/suitability of a structure)

(same as "Modelling")