Composite Grid-stiffened manufacturing Method: low cost & high quality

Ref-Nr: TD2017-35

Technology abstract

A true one-shot cost-efficient high-quality manufacturing methodology for producing integrated grid-stiffened and lattice structures with integrated attachment and load introduction zones without cutting fibres and at a 60% fibre fraction. The supplier has developed and patented this revolutionary technology. The advantages of the solution are its superb specific stiffness, mass efficiency, and cost per unit weight.

The tech-owner is a large SME with decades of experience in working with space and aerospace related engineering challenges. They work with both space (ESA and other space agencies) and non-space companies and therefore have thoroughly understanding of the transfer possibilities of this technology. We can recommend them as both a business- and developmentpartner.

- Derk Schneemann -

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Technology Description

Pre-preg grid-stiffened and lattice structures produced from continuous fibre tows exhibit lower mass and manufacturing costs compared to conventional composite and metallic structural architectures for a wide variety of applications. The suitability of the technology for various applications is a function of the mass efficiency, cost constraints, the complexity of geometry and required functionality. The currently identified applications where grid and lattice structures are guaranteed to deliver cost savings and performance improvements are the following:

  • Space and launcher structures: Satellite central tubes, booms and shear webs, stiff instrument benches, payload adapters and dispensers, launcher interstages and skirts, payload fairings
  • Manned and unmanned aviation: Fuselages and fuselage panels, equipment frames, advanced wings & aero-surfaces, helicopter fuselage panels
  • Maritime/offshore: Hulls, lighter structures at height, high-load corrosion sensitive structures • Automotive: Chassis (sub-)structures, equipment frames
  • Scientific and industrial machine structures: High-accuracy/high-speed processing and placement machines, heavy machinery, large precision instruments/antenna’s The expertise and know-how offered is a combination of the following: • High quality, repeatable, predictable and integrated one-shot manufacturing process for uncut composite pre-preg grid and lattice structures. The process can be entirely automated.
  • Automated and validated analysis and optimization approach for the full design cycle of a grid or lattice structure shapes and functions ranging from simple up to highly complex.

Innovations & Advantages

Compared to conventional structural architectures (e.g. sandwich, metallic and composite stiffened skin, etc.) the developed solution has demonstrated the following (simultaneous) advantages through rigorous case studies: 1. Component cost reductions up to 35% 2. Lead time reduction up to 20% 3. Mass reduction up to 30% The main innovative aspects of the proposed technology differentiating it from other lattice or grid architectures provided are: - Pre-preg materials are used ensuring superior quality and stiffness properties compared to dry/wet wound lattice structures. The specific stiffness of these is circa two times lower. - As opposed to other processes that employ pre-pregs for lattice structures manufacturing, the fibres remain uncut (continuous) in the nodal region. This is ensured by the developed know-how and smart tooling design. The specific strength of the nodal regions for the developed process is circa two times higher than when cutting the fibres at the node. - All developed structural features are integrated in a one-shot production process. This means that the part only undergoes curing once and all the complex features are integrated already during the single layup phase of the component. This concerns the following aspects: a) All types of load introduction areas (edge zones) can be provided and are part of the one-shot manufacturing process (metallic bonded and bolted, composite edge, etc.). b) All types of local equipment attachment areas for various strength levels have been developed and validated. These are part of the one-shot manufacturing process. c) Local skin reinforcements can be introduced anywhere around the structure also as part of the one-shot process. - Planar, curved and (complex) body of revolution structures can be produced with process. - The process can be entirely automated – all aspects deal with manufacturing sequences that are 100% replicate-able by an industrial tow/tape placement robot.

Further Information

  1. Currently the technology can be used to produce structures with operational temperature limits between -170 and +250 deg C depending on loading as a function of temperature.
  2. A specific benefit applicable e.g. for central cylinders is their structural “transparency” – lattice architecture. Effectively relatively large objects can be passed through the structure and it is easily reachable everywhere. This leads to ease of integration, provides unique advantages for assembly, but also for eventual disassembly of the hardware.
  3. The technology offers unlimited design freedom, which leads to mass reduction, but also helps in complying with various configuration limitations and equipment placement requirements.
  4. Design flexibility and on-demand customization is another strong feature of the architecture. A design can be modified last-minute with minor impact on the production process, which can be adjusted causing a max 2 days of delay in manufacturing. In the case of lattice structures, which are “transparent”, cable or piping routing can be defined and re-defined at any point in time since it does not affect the design to any significant extent
  5. Material damping levels of the grid are higher than those of conventional composite structures. This leads to lower shock propagation levels delivered by the architecture.
  6. The architecture offers better demise-ability at re-entry

 

Current and Potential Domains of Application

Non-space: manned and unmanned aviation, helicopters, maritime/offshore, automotive, scientific and industrial machine structures. Space: spacecraft structures and instruments, launcher components,