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Curved pultrusion? No longer an oxymoron | CompositesWorld

The U.S. Air Force conducted on-base and cross-country mission and performance evaluations of Beta’s composites-intensive CTOL aircraft, hitting key milestones.

Horizontal and vertical tail, aileron, and rudder and elevator will be developed and manufactured for the lift + cruise aircraft, scheduled to enter service in 2026. Aluminum Alloy Bus Bar

Curved pultrusion? No longer an oxymoron | CompositesWorld

In addition to its composite aircraft, Overair will support infrastructure, aircraft operations and training to ensure a comprehensive and sustainable AAM ecosystem.

This initial project under the Space Act Agreement is focused on studying and developing high-performance battery cells, as well as performing safety testing, to achieve purpose-built solutions for electric aircraft.  

AeroZero TPS, applicable for metals and composites, will protect critical battery housing and parts in the Lilium Jet eVTOL aircraft from burn through and risk of thermal runaway.

V-tail, five-passenger aircraft builds on the vison of the S-A1, designed with a priority on safety and a focus on sustainability.

Through a strategic partnership, the companies introduce the FiberScanner3D module, dedicated to bringing more rapid, reliable and robust fiber structure characterization methods to lab settings.

The new alliance will broaden National Composites’ capabilities in SMC and BMC and tooling, while providing customers with comprehensive solutions, from initial design to final delivery.

A new ASTM-standardized test method established in 2022 assesses the compression-loaded damage tolerance of sandwich composites.  

Composites automation specialist increases access to next-gen technologies, including novel AFP systems and unique 3D parts using adaptive molds.

Combined LSAM and five-axis CNC milling capabilities will optimize D-Composites’ production services, flexibility and cut time and cost for composite tooling manufacture.

Evaluation of CFRTP m-pipe through Element’s U.K. facility aims to qualify the system for new operating environments.

Inshore vessel is the largest yet to incorporate the recyclable thermoplastic resin, promotes future sustainability in boat manufacturing.

Projects use Duplicor prepreg panels with highest Euroclass B fire performance without fire retardants for reduced weight, CO2 footprint in sustainable yet affordable roofs, high-rise façades and modular housing.

Available as filament and granules for extrusion, new wood composite matches properties yet is compostable, eliminates microplastics and reduces carbon footprint.

A recent study conducted on vacuum-infused thermoplastic fiber-metal laminates has highlighted the performance benefits behind using TFP’s nonwovens for consistent, uniform bondlines and interfacial bonding.

To incorporate more environmentally conscious practices into its manufacturing processes, VSC is working with Carbon Conversions to reclaim, recycle and reuse its carbon fiber materials.

Switching from prepreg to RTM led to significant time and cost savings for the manufacture of fiberglass struts and complex carbon fiber composite foils that power ORPC’s RivGen systems.

Through a strategic partnership, the companies introduce the FiberScanner3D module, dedicated to bringing more rapid, reliable and robust fiber structure characterization methods to lab settings.

Automated fiber placement develops into more compact, flexible, modular and digitized systems with multi-material and process capabilities.

Available as filament and granules for extrusion, new wood composite matches properties yet is compostable, eliminates microplastics and reduces carbon footprint.

A recent study conducted on vacuum-infused thermoplastic fiber-metal laminates has highlighted the performance benefits behind using TFP’s nonwovens for consistent, uniform bondlines and interfacial bonding.

Switching from prepreg to RTM led to significant time and cost savings for the manufacture of fiberglass struts and complex carbon fiber composite foils that power ORPC’s RivGen systems.

Sara Black’s 2015 report on the development of snap-cure epoxies for automotive manufacturing still resonates today. 

CW explores key composite developments that have shaped how we see and think about the industry today.

Knowing the fundamentals for reading drawings — including master ply tables, ply definition diagrams and more — lays a foundation for proper composite design evaluation.

As battery electric and fuel cell electric vehicles continue to supplant internal combustion engine vehicles, composite materials are quickly finding adoption to offset a variety of challenges, particularly for battery enclosure and fuel cell development.  

Performing regular maintenance of the layup tool for successful sealing and release is required to reduce the risk of part adherence.

Increasingly, prototype and production-ready smart devices featuring thermoplastic composite cases and other components provide lightweight, optimized sustainable alternatives to metal.

The composite pressure vessel market is fast-growing and now dominated by demand for hydrogen storage.

The burgeoning advanced air mobility (AAM) market promises to introduce a new mode of transport for urban and intercity travelers — particularly those who wish to bypass the traffic congestion endemic to the world’s largest cities. The electric vertical take-off and landing (eVTOL) aircraft serving this market, because they depend on battery-powered propulsion, also depend on high-strength, high-performance composite structures produced at volumes heretofore unseen in the aerospace composites industry. This CW Tech Days will feature subject matter experts exploring the materials, tooling and manufacturing challenges of ramping up composites fabrication operations to efficiently meet the demands of a challenging and promising new marketplace.

Manufacturers often struggle with production anomalies that can be traced back to material deviations. These can cause fluctuations in material flow, cooling, and cure according to environmental influences and/or batch-to-batch variations. Today’s competitive environment demands cost-efficient, error-free production using automated production and stable processes. As industries advance new bio-based, faster reacting and increased recycled content materials and faster processes, how can manufacturers quickly establish and maintain quality control? In-mold dielectric sensors paired with data analytics technology enable manufacturers to: Determine glass transition temperature in real time Monitor material deviations such as resin mix ratio, aging, and batch-to-batch variations throughout the process Predict the influence of deviations or material defects during the process See the progression of curing and demold the part when the desired degree of cure, Tg or crystallinity is achieved Document resin mix ratios using snap-cure resins for qualification and certification of RTM parts Successful case histories with real parts illustrate how sensXPERT sensors, machine learning, and material models monitor, predict, and optimize production to compensate for deviations. This Digital Mold technology has enabled manufacturers to reduce scrap by up to 50% and generated energy savings of up to 23%. Agenda: Dealing with the challenge of material deviations and production anomalies How dielectric sensors work with different composite resins, fibers and processes What is required for installation Case histories of in-mold dielectric sensors and data analytics used to monitor resin mixing ratios and predict potential material deviations How this Digital Mold technology has enabled manufacturers to optimize production, and improve quality and reliability

SolvaLite is a family of new fast cure epoxy systems that — combined with Solvay's proprietary Double Diaphragm Forming technology — allows short cycle times and reproducibility. Agenda:  Application Development Center and capabilities Solutions for high-rate manufacturing for automotive Application examples: battery enclosures and body panels

OEMs around the world are looking for smarter materials to forward-think their products by combining high mechanical performance with lightweight design and long-lasting durability. In this webinar, composite experts from Exel Composites explain the benefits of a unique continuous manufacturing process for composites profiles and tubes called pull-winding. Pull-winding makes it possible to manufacture strong, lightweight and extremely thin-walled composite tubes and profiles that meet both demanding mechanical specifications and aesthetic needs. The possibilities for customizing the profile’s features are almost limitless — and because pull-winding is a continuous process, it is well suited for high volume production with consistent quality. Join the webinar to learn why you should consider pull-wound composites for your product. Agenda: Introducing pull-winding, and how it compares to other composite manufacturing technologies like filament winding or pultrusion What are the benefits of pull-winding and how can it achieve thin-walled profiles? Practical examples of product challenges solved by pull-winding

Composite systems consist of two sub-constituents: woven fibers as the reinforcement element and resin as the matrix. The most commonly used fibers are glass and carbon, which can be processed in plane or satin structures to form woven fabrics. Carbon fibers, in particular, are known for their high strength/weight properties. Thermoset resins, such as epoxies and polyurethanes, are used in more demanding applications due to their high physical-mechanical properties. However, composites manufacturers still face the challenge of designing the right cure cycles and repairing out-of-shelf-life parts. To address these issues, Alpha Technologies proposes using the encapsulated sample rheometer (premier ESR) to determine the viscoelastic properties of thermosets. Premier ESR generates repeatable and reproducible analytical data and can measure a broad range of viscosity values, making it ideal for resins such as low viscous uncured prepreg or neat resins as well as highly viscous cured prepregs. During testing, before cure, cure and after cure properties can be detected without removing the material from the test chamber. Moreover, ESR can run a broad range of tests, from isothermal and non-isothermal cures to advanced techniques such as large amplitude oscillatory shear tests. During this webinar, Alpha Technologies will be presenting some of the selected studies that were completed on epoxy prepreg systems utilizing ESR and how it solves many issues in a fast and effective way. It will highlight the advantages of this technique that were proven with the work of several researchers. Moreover, Alpha Technologies will display part of these interesting findings using the correlations between the viscoelastic properties such as G’ and mechanical properties such as short beam shear strength (SBS).

Surface preparation is a critical step in composite structure bonding and plays a major role in determining the final bonding performance. Solvay has developed FusePly, a breakthrough technology that offers the potential to build reliable and robust bonded composite parts through the creation of covalently-bonded structures at bondline interface. FusePly technology meets the manufacturing challenges faced by aircraft builders and industrial bonding users looking for improved performance, buildrates and lightweighting. In this webinar, you will discover FusePly's key benefits as well as processing and data. Agenda: Surface preparation challenges for composite bonding FusePly technology overview Properties and performance data

Venue ONLY ON-SITE @AZL Hub in Aachen Building Part 3B, 4th Floor Campus Boulevard 30 52074 Aachen Time: January 31st, 2024 | 11:00-16:00h (CET) This first constitutive session will shape the future of the workgroup. ✓ Insights into solutions for e.g. circularity, recycling, sustainability, end of life etc. ✓ Interactive exchange along the value chain to tackle these challenges: Share your input in the “World Café” workshop session! ✓ Are you a solution provider? Take your chance and present your solution approach in a short 5-minute pitch. Get in touch with Alexander.  

The Transformative Vertical Flight (TVF) 2024 meeting will take place Feb. 6–8, 2024 in Santa Clara, California, in the heart of Silicon Valley and will feature more than 100 speakers on important progress on vertical takeoff and landing (VTOL) aircraft and technology. 

The EPTA – European Pultrusion Technology Association in cooperation with the American Composites Manufacturers Association (ACMA) invites you to the 17th World Pultrusion Conference which takes place on 29 February – 1 March 2024 in Hamburg, Germany. Visit the most important event in Europe in the market for pultruded fiber reinforced materials  This conference takes place every two years and is the meeting point of the European and worldwide Pultrusion Industry. More than 25 international speakers from Finland, Belgium, Germany, France, Spain, The Netherlands, Turkey, UK, USA, Canada and others will present practical presentations about innovative applications, technologies and processes. Equally current market trends and developments are on the agenda. This World Pultrusion Conference takes place again in the week before the JEC World Composites Show (5-7 March 2024, Paris). The presentation language will be English. Please finde here the full program and booking opportunities. We appreciate very much welcoming you in Hamburg! Inquiries should be requested by email: info@pultruders.com

The Program of this Summit consists of a range of 12 high-level lectures by 14 invited speakers only. Topics are composite related innovations in Automotive & Transport, Space & Aerospace, Advanced Materials, and Process Engineering, as well as Challenging Applications in other markets like Architecture, Construction, Sports, Energy, Marine & more.

JEC World in Paris is the only trade show that unites the global composite industry: an indication of the industry’s commitment to an international platform where users can find a full spectrum of processes, new materials, and composite solutions.

Charting the Skies of Tomorrow: The Sustainable Aviation Revolution Welcome to a new era of air travel where innovation meets sustainability. Electric, hybrid-electric and hydrogen-powered aircraft represent a promising path to reach climate neutrality goals, with the aviation industry and governments jointly pushing boundaries to bring disruptive aircraft into service by 2035. From cutting-edge technologies to revamped regulations and greener airports, the pursuit of sustainable aviation requires unparalleled collaboration throughout the whole aviation value chain and ecosystem. Join us at the Clean Aviation Annual Forum from 5 until 6 March 2024, as we navigate towards cleaner skies together.

Thousands of people visit our Supplier Guide every day to source equipment and materials. Get in front of them with a free company profile.

Jetcam’s latest white paper explores the critical aspects of nesting in composites manufacturing, and strategies to balance material efficiency and kitting speed.

Arris presents mechanical testing results of an Arris-designed natural fiber thermoplastic composite in comparison to similarly produced glass and carbon fiber-based materials.

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Initial demonstration in furniture shows properties two to nine times higher than plywood, OOA molding for uniquely shaped components.

The composite tubes white paper explores some of the considerations for specifying composite tubes, such as mechanical properties, maintenance requirements and more.

Foundational research discusses the current carbon fiber recycling landscape in Utah, and evaluates potential strategies and policies that could enhance this sustainable practice in the region.

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ST Engineering MRAS discusses the importance of addressing human factors to reduce separator inclusion in bonded structures.

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To incorporate more environmentally conscious practices into its manufacturing processes, VSC is working with Carbon Conversions to reclaim, recycle and reuse its carbon fiber materials.

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Novel material to combine Ohoskin’s leather alternative made from orange and cactus byproducts with ReCarbon’s recycled carbon fiber.

The three-year strategic collaboration will help boost the company’s growth, reinforce its commitments to become carbon neutral by 2040 and innovate more circular chemicals and materials.

Oak Ridge National Laboratory's Sustainable Manufacturing Technologies Group helps industrial partners tackle the sustainability challenges presented by fiber-reinforced composite materials.

Eco-friendly carbon fiber slashes carbon footprint by half through renewable energy, a commitment echoed in SGL’s Lavradio biomass plant set to reduce CO2 emissions by 90,000 tons.  

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Radius-Pultrusion process offers linear or curved profiles.

Fig. 1: Curve-capable pultrusion process. For most of its history, the pultrusion process has been limited to production of linear profiles. But Thomas Technik & Innovation’s (Bremervörde, Germany) Radius-Pultrusion technology successfully turned out this pipe coil prototype for an oil company. Source: Thomas Technik

Fig. 2: Developmental licensing. Licensee KraussMaffei’s (Munich, Germany) iPul machine, with direct resin injection system and incorporated Radius-Pultrusion technology, is capable of pultruding either curved or straight profiles. Source: KraussMaffei

Fig. 3: Enabling elegant arcs. A close-up of a curved channel (arc profile) made by the Radius-Pultrusion process. Source: Thomas Technik

Fig. 4: Curved profiles demonstrate strength. Radius-Pultrusion curved profiles sustain 100 kg load in strength demonstration. Source: Thomas Technik

Fig. 5: Autocomposites pultruded bumper beams? This graphic rendering depicts licensee Shape Corp.’s (Grand Haven, MI, US) Radius-Pultrusion system, which will be used to produce curved automotive bumper beams. Source: Shape Corp.

In the early days of composites manufacturing, the materials for building fiber-reinforced plastic/composite parts were laid into molds by hand. Hand layup is still common in the industry, but automated processes — notably pultrusion, filament winding, automated tape layup (ATL) and others — have been developed along the way to replace or streamline manual operations.

Pultrusion was one of the first automated processes. Patented in 1959 by W. Brandt Goldsworthy (1915-2003), pultrusion is an automated, computer-controlled process for manufacturing linear, constant-cross section, fiber-reinforced composite profile parts quickly, consistently and endlessly, and then reliably cutting them into pre-programmed lengths.

Although early models could process only unidirectional reinforcements, later system designs have enabled the addition of multiaxial fabrics during processing. Typically a thermoset process, pultrusion also has been adapted for composite profiles with thermoplastic matrices.

Historically, pultrusion has been limited in that the profiles it generates are oriented along a linear axis. In a word: straight. But nonlinear pultruded profiles were envisioned almost from the beginning. Goldsworthy and other composite pioneers soon asked, Why can’t we make curved pultrusions?

The earliest curved variant was probably Goldsworthy’s Pulformer, patented and built in the early 1980s by his team as a contender for production of curved thermoset composite leaf springs for the automotive industry. The Pulformer combined step compression molding with pultrusion material infeed technology to enable continuous, automated manufacture of curved parts and parts with non-uniform cross sections. In the end, the technology didn’t fulfill the envisioned potential: Composite leaf springs are found on cars today, but they are molded, mostly by RTM. One automaker in the US and another in Japan bought Pulformers and did considerable research, but no Pulformed leaf springs were installed on production cars. Curved pultrusion technologies conceived by other machinery manufacturers were similarly unable to attain commercial success.

Nearly four decades later, however, Thomas Technik & Innovation (TTI), part of Thomas Holding (Bremervörde, Lower Saxony, Germany), is reporting considerable success with its version of curved pultrusion technology, developed in part with financial support from the European Union and Lower Saxony.

Notably, TTI’s principal business focus is healthy sleep: Since 1957, it has invested in research, development and production of beds for homes, hospitals, rehabilitation and care facilities, and mobile applications in trucks and recreational vehicles. Two decades ago, that led to composites production — using carbon and glass fiber, and more recently natural fiber-reinforced polymer composites — initially to improve the comfort of its bedding systems. One of its core composite competencies, as a result, is pultrusion.

Trademarked Radius-Pultrusion, the company’s curve-capable technology operates like conventional linear pultrusion, but with some important differences, as explained by Klaus Jansen, CEO of TTI.

Conventional pultrusion uses a reciprocating pulling system to draw dry fibers through a resin chamber, then through a heated forming/curing tool (die), and then into an automated cutoff saw. The key here is that the part profile is cured as it is pulled through a stationary die. A constant cross-section, linear profile is continuously produced by this system.

“In the Radius-Pultrusion process,” Jansen explains, “the heated die tool is no longer stationary but works as the upstream, and only moving, stage of its pulling system. The heated die tool is a reciprocating puller, and a stationary gripper on the downstream end of the line opens and closes as programmed, but does not travel. The die tool grips incoming raw material at the upstream end of the line, then moves downstream, curing the profile as it proceeds toward the gripper unit. As the die moves downstream, the gripper remains open and the cured profile is pushed through it, toward the automated cutoff saw. When the die reaches the downstream gripper, the gripper closes, firmly holding the cured profile while the die opens and again moves upstream to pull and cure the next section of material. This essential difference — a moving die — allows the material to be pulled around a curve. The result is a system that can continuously produce either a linear constant cross section or a constantly curved profile,” Jansen says.

As with conventional linear pultrusion, Radius-Pultrusion is a wet process. The fibrous materials are wet-out either by resin injection or in an open bath where local environmental regulations permit.

TTI has vetted its system with a variety of composite materials, including glass or carbon fiber impregnated with vinyl ester, epoxy, polyurethane, acrylate esters and others. Multiaxial fabrics are commonly incorporated, as well as veils, which are especially useful for helping drape the material in the mold, Jansen says. What is needed in reinforcements for Radius-Pultrusion is material suited for what Jansen calls endless draping, to enable the material to follow the curve. “It must be flexible,” Jansen says, noting that many woven materials are, indeed, flexible enough to be pulled around the curve.

For a constant curve in space, at least five degrees of freedom are necessary. “In addition to the horizontal x-axis of linear pultrusion, curved pultrusion needs up to four additional axes,” Jansen explains, naming the vertical y-axis, transversal z-axis and rotational axes (clockwise and counterclockwise), which would be added, for example, to make pipe (Fig. 1).

Jansen says TTI is now building machines that can produce linear profiles and — with some modification — curved parts with radii greater than 2,000 mm), incorporating the required additional axes of freedom. “Where the radius is parallel to the long axis, rotation and linear movement is vertical; and where the radius is parallel to the short axis, rotation and linear movement is horizontal,” Jansen says. Typical parts, where the radius is parallel to the long axis, are bumper beams that are created with a vertical orientation of curve. Parts that can better be created with a horizontal curve include the thin reinforcement profiles for glass roofs on cars.

For smaller-sized curved parts, with radii less than 2,000 mm, a different, custom design is offered. For these, the machine rotates about a central axis, which may be either horizontal or vertical. Parts for bicycle wheel rims are one example of what is possible on this type of machine. TTI, in fact, is in discussion with and making proof-of-concept carbon epoxy rim components for a bicycle manufacturer interested in the potential of Radius-Pultrusion. The part radius here is about 300 mm.

“Every kind of profile that is somehow curved can be manufactured by pultrusion now,” says Jansen.

In addition to producing parts for customers on its Radius- Pultrusion machines, TTI is licensing the technology to others. “We are currently developing new pultrusion lines together with KraussMaffei Technologies in Munich, Germany, one of the biggest European injection molding and reaction technology manufacturers,” Jansen reports. “Complete lines, especially 
for fast or demanding resins, such as polyurethane, epoxy and reactive polyamide, are under development and will be sold through KraussMaffei, using the Radius-Pultrusion pulling units and controls from TTI, with the possibility for the customers to license the technology for curved profiles” (Fig. 2).

TTI also has a partner in Japan that is selling the machinery there, Jansen says, adding that he is not authorized to identify the company or product, but says the parts might be for infrastructure elements. “They won’t tell us,” Jansen says. “Nearly every company that has visited us expressed considerable interest and often asked for certain profiles for evaluation — without identifying the use for these profiles. They only tell us the specifications for the profile they want” (e.g., Figs. 3 and 4).

Another major licensing agreement TTI has recently signed, and one it can discuss, is with Shape Corp. (Grand Haven, MI, US). Although it is a global supplier of multiple material structural components, primarily in the automotive sector, Shape also sells to a diversified group of customers in other markets, says John Keene, Shape’s marketing communications lead.

The agreement calls for TTI to supply its Radius-Pultrusion machines and technology to Shape to enable manufacture of automotive bumper beams (Fig. 5). Jansen expects the first machine will be operational this year. “During the last year, Shape and Thomas Technik formed a real partnership for the development of a new generation of automotive profiles, and we are looking forward to future joint-development projects,” Jansen says. “The ability of Radius-Pultrusion to manufacture curved and hollow profiles is a perfect fit to both our strategies to bring new technologies to the customer.”

Today, most composite automotive bumpers are non-load-bearing injection or compression molded thermoplastics. Thermoset bumper beams are less common because they are weightier and more brittle than comparable thermoplastic bumpers. Steel beams are still the most widely used because of their low cost, but compared to composites, they add weight to the vehicle and leave the part corrosion-prone. Further, those who use steel sacrifice opportunities for parts consolidation in manufacturing. This also results in less energy absorption during a crash, thus reducing passenger protection.

Toby Jacobson, Shape’s plastic materials and process manager/advanced product development, adds that Shape chose TTI’s Radius-Pultrusion process primarily for its automation, increased speed and ability to produce tubular and multiple hollow cross sections.

Jacobson identifies the material systems Shape chose following extensive trials to develop a laminate architecture and resin formulation that best works with Radius-Pultrusion: “While the process provides the flexibility to run nearly any type of thermoset resin, our resin of choice is polyurethane,” he says. “It offers exceptional toughness properties at reasonable cost while allowing us to achieve some very fast production rates. For reinforcements, we are running unidirectional, biaxial and triaxial noncrimp [stitched nonwoven] fabrics. We’re also pulling some individual unidirectional tows when necessary. While most of the current interest is with carbon fiber, this process will excel with fiberglass and a variety of other reinforcements.”

Keene adds, “This combination of extensive process and product design research, paired with production trials and physical testing, has Shape in position to install their first curved pultrusion machine in 2017, in preparation for 2019 model year production.”

Curves make the difference in cars and more

Historically, linear pultrusion has not stimulated much interest in the automotive industry because there are simply very few long, straight beams in passenger cars. Almost all automotive parts are curved. Given that reality, curved pultrusion offers the opportunity to open some doors.“The ability to reliably pultrude a constant curvature could result in replacing steel in a number of applications,” says Michael Connolly, program manager for Urethane Composites at Huntsman Polyurethanes (Auburn Hills, MI, US). He names bumper beams, roof beams, front-end support systems, door intrusion beams, chassis rails and, perhaps, transmission tunnels as potential curved pultruded car parts. “Pultrusion is efficient, in that it is automated, low-labor and low-capital, compared to other composite processing equipment,” Connolly sums up, “and can have a low scrap rate compared to RTM and other molding processes. I think the automotive community will start to see pultrusion as something they might be able to exploit, now that curved pultrusion may be available and reliable.”

Such systems — proven reliable and capable of commercial series production — could make a substantial difference in a wide range of other market applications as well. Potential output includes bicycle parts, as well as a host of curved shapes unique to infrastructure, architecture and building construction. In time, a wide variety of curved parts now made in individual molds might be produced continuously by curved pultrusion. 

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Curved pultrusion? No longer an oxymoron | CompositesWorld

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