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Making Load Carrying Fibre Composite Structures More Accessible

Making Load Carrying Fibre Composite Structures More Accessible

I am often asked about the right definition of the term ‘composite material’. Normally, it is broadly used to describe fiber-reinforced polymers.

So, what does it take to make load carrying fiber composite structures more accessible?

From a functional point of view, such materials are very attractive. High-performance composites possess excellent mechanical and chemical characteristics, making them applicable for various industries such as aerospace, automotive, medtech and leisure.

Remouldability and high fracture toughness of thermoplastic-based matrix systems led to new applications with short cycle times in production and high damage tolerance.

carbon fibre
Carbon fiber-reinforced carbon (C/C, CFRC) is a high-strength composite, that consists of a carbon or graphite matrix, that is fortified with very strong carbon fibers. (image by SGL Carbon)

However, the comparably high costs associated with carbon fiber composite parts to its aluminium or steel contenders, remain a constraining factor.

Clearly, a higher degree of freedom to optimize the part geometry and the fiber layup in combination with increased automation in manufacturing will reduce the current constraint.

Toward a game-changing solution for composite production

When screening the process landscape, 3D printing, an additive manufacturing technology, shows the highest potential to deliver on those demands for manufacturing.

Several players currently work on applying this technology to offer a competitive 3D printing approach for the manufacturing of composite parts in series. It is easier said than done, however, as it requires:

  • the aggregated understanding of the material (high fiber-volume content)
  • the design (optimized fiber layup)
  • and production (printing and finishing).

All parts are necessary to reach the required consistent part quality (low void content) and the cost structure.

Does it look like the holy grail of composite manufacturing? Let’s have a look at what is already accessible today. Basically, it is about developing the optimal bundle including advanced software technologies, innovative production machinery equipment, and industry-standard material with the goal to meet the expected industrial standards while lowering both complexity and costs.

Industry-standard MATERIALS - Toward true anisotropy

Nowadays, the production of many composite parts starts with a technical textile having constant fiber-volume content. In this case, the full freedom in designing a part based on the expected load cases is already very limited from the very beginning of the value chain.

In fact, this results in less than average material-efficiency in many applications with associated negative impacts on both the environmental footprint and cost structure.

Well, wouldn’t it be valuable to place fibers only exactly where needed?

In order to make this vision a reality, the software component of the whole value chain plays a crucial role.

The SOFTWARE - Quickly manufacture the most optimal designs

In an ideal world, one would input the load cases and all boundary conditions in a tool which would, in a matter of seconds, engineer the whole part from raw material to finished state. This output would show the optimal technical and economical value chain including materials, processes, quality tests, logistics…selected from a mega-database.

While keeping this vision in mind, let’s go back to our composite structures. Today, it is already possible to quickly define optimal fiber designs through integrated FEA simulation tools.

Iterative design process - Structural simulation is used to define load tailored fiber layup.

Just imagine two connected features. Firstly, one design engineer’s toolkit enables variable fiber angles and designs that comprise plastic regions exempt from fiber reinforcements to bring new designs to life. It features an intuitive manual workflow that gives the user full control over fiber placement throughout the part. In addition, intelligent fiber lay-up proposals are made based on user inputs to accelerate the design process.

Secondly, the design output, together with application-specific data, are fed into a finite element analysis (FEA) simulation software. There, designs can be structurally validated before being produced. This enables a quick iterative design process that results in an optimized design (results within minutes).

The HARDWARE - Produce industry-grade serial parts

As mentioned before, 3D printing shows high potential when it comes to design flexibility. As we are looking at continuous fiber reinforced structures, technologies based on filaments – especially FDM/FFF – are in focus.

Here, two options are available. Either with in-situ consolidation during the printing process or with post-consolidation. Both have their pros and cons. The latter one is attractive, especially when working with thermoplastic materials. In fact, this 2-stage process ensures part quality, reproducibility and cost competitiveness for series production applications.

Last but not least, it allows welding multiple parts together, thus enabling true 3d fiber orientation in the final consolidated part.

Example of a 2-stage process to produce a helicopter door hinge with true 3d fiber orientation. (Collaboration with fhnw)

Beyond - the next steps

Personally, I am really excited that novel value-chains are currently being developed and brought to market, thus supporting the democratization of load-carrying fiber composite structures.

The fact that we are not the only firm working on this topic shows that time has come for a change. In such early stages, it is crucial to have a clear understanding of the competitors’ landscape.

It is about entering the holistic serial industrial parts market, not solely focusing on the few other players within our (currently) small environment. In the background, all players offering a proposal for an innovative solution to produce such composite structures with both optimized material efficiency and lower overall costs contribute to the acceleration of market adoption.

About the author

During my professional path, I was lucky to be in contact with various high-performance composite solutions. First at SGL Carbon with products including carbon-ceramic brake discs for high-performance automotive braking characteristics, graphite electrodes with their unique sublimation property in steel-making, continuous carbon-fiber reinforced polymers in medical applications for their x-ray transparency and more.

Although I love seeing the great engineering work leading to such high-performing products, it frequently bothered me that these products would not become more accessible. Mostly because of the sheer amount of resources necessary to design and produce them.

That was certainly a key driver when I decided to move to 9T Labs. Leaving an established corporation to join a young innovative company could be seen as risky. But the reward to work on making load-carrying fiber composite structures as accessible for series production as metal parts together with a focused team is something I enjoy every minute!

Last but not least, we are offering our second webinar on April, 2nd 2020. Then, our CEO Martin Eichenhofer is going to explain how our Red Series technology enables “New market opportunities for high-performance composites in structural metal and composite applications”. Please register here (it’s FREE).

"The convergence of both novel materials and innovative production value-chains go much further than simple existing part substitution. They enable the emergence of totally new solutions."

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