Leveraging Fiber-reinforced Additive Manufacturing Through Hybridization and Digital Design Techniques into Practice

Additive manufacturing of fiber-reinforced plastics is gaining more and more interest. This is case, as fiber-reinforced plastics display impressive strength and stiffness properties. These positive attributes become even more striking, once they are correlated to their density; hence their mass specific strength and stiffness properties are remarkable. Yet, their widefield deployment is often thwarted by their lack of load transmission in technical applications. Or in other words, within technical environments it is challenging to consider additive manufacturing of fiber-reinforced plastic materials, as one needs to defy the need for introducing loads originating from surrounding structural elements into these fiber-reinforced plastics by means of bolts and rivets. This is a pity, as structures being additively manufactured yielding fiber-reinforced plastics, do not only come at a lighter weight, they – in case they substitute complex metal parts – also come at lower costs. With this contribution, we present a viable approach of leveraging additively manufactured fiber-reinforced plastics into practice. We combined two clear principles. The first is rather straight forward, the consideration of digital design techniques. We have done so, by a sequence of topology optimization, size and shape optimization and detailed analysis. By following this sequence, not only load transmission paths are exploited to the full extend, but moreover the peculiarities of fiber-reinforced plastics are considered. Secondly, we follow a clear hybridization strategy, where metallic bushings are placed in critical load introduction spots. Utilizing topology optimization, bushings made out of steel are derived. Exactly these bushing are than transmitting loads via bolts from surrounding structural elements into fiber-reinforced plastics. This is realized in such a fashion, that high strength and stiffness capabilities of the incorporated carbon fibers are actually taken advantage of. It is keen, that these bushings are designed, such that they are performant under mechanical and thermal loading and on top allow fast and cost-effective placement during or right after the additive manufacturing process. Following these two principles, additive manufacturing of fiber-reinforced parts becomes even more significant. The reasons for this are cost reduction and facilitation of mechanical load transmission capability.