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    Narrow UD tapes to bridge the ATL-AFP gap
    It is well understood that automated tape laying (ATL) and automated fiber placement (AFP) were the enabling technologies in the application of carbon fiber composites in major aerostructures for the Boeing 787 and the Airbus A350 aircraft. Prior to the development of these planes, composites had been applied in gradually increasing amounts in commercial aircraft for more than 30 years, but mainly in secondary structures using hand layup and some automated manufacturing processes.

    With the 787 and the A350, however, Boeing (Seattle, Wash., U.S.) and Airbus (Toulouse, France) responded to demand for lighter weight aircraft, which accelerated adoption of composite materials and processes for use in fuselage skins, stringers, frames, wing skins, wing spars, wing boxes and tail structures. ATL and AFP led the charge, allowing each OEM, and their suppliers, to efficiently lay down large amounts of prepregged UD-tape and tows.

    ATL found a place fabricating wing structures, which, being modestly contoured, took advantage of the wide format (3, 6 or 12 inches) of the tape products, which could be laid down quickly. However, what ATL offered in speed and volume it sacrificed in conformability.

    AFP, on the other hand, which lays down multiple tows 0.125 to 0.5 inch wide, found a place fabricating fuselage and other more contoured structures that demand maximum flexibility and conformability. However, what ATL offered in conformability it sacrificed in speed and volume.

    Further, as enabling as these technologies were, they clearly reflected the state of ATL/AFP art at the time of the planes’ initial development, almost 20 years ago now. Indeed, the production pace of the 787 and the A350 (each now less than 10/month in light of the coronavirus pandemic) is well-aligned with previous-generation ATL/AFP technologies, which are relatively slow. These technologies also depend on human operators to provide in-process visual inspection and quality control, checking for the laps, gaps, wrinkles, foreign object debris (FOD) and other flaws endemic to the automated laydown process. This quality control step represents a significant bottleneck in the manufacture of composite structures.

    But as commercial aircraft manufacturers look to the future (well beyond the coronavirus pandemic) and the aircraft they will develop — particularly new single-aisle (NSA) programs to replace the Boeing 737 and Airbus A320 — shipset volumes are likely to be on the order of 60-100 per month. This demands composite materials and process capability orders of a magnitude more efficient than those used to fabricate structures for the 787 and the A350.

    Honeycomb panel applications
    EconCore has granted plastic film company Renolit a license for the continuous production of honeycomb panel.

    Renolit has reportedly used the honeycomb in its Gorcell range of products for automotive, outdoor kitchens, truck superstructures, and bakery panels applications. More recently, Renolit has produced products for gardens, balconies and terraces made with honeycomb panels.

    According to EconCore, the honeycomb has helped Renolit improve panel planarity, reduce golf ball effect, and create smooth, scratch free surfaces.

    The Renolit Gorcell production process includes film unwinding, vacuum forming, core calibration, skin layer lamination, panel calibration and cutting.

    This story uses material from EconCore, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier.

    Scanning electron microscopy and digital image correlation observations reveal the failure mechanisms of overmolded hybrid composites. The failure behavior of overmolded hybrid composites is mainly CFRT laminates failure for all cases. The evolution of non-uniform strain fields indicates that the fracture of overmolded thermoplastic composites may initiate at the edges and spread out to the far fields.


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