The structural components of the Delft Hyperloop 03 pod are all made of carbon fiber composite materials. These materials are well-known for their high strength, while being extremely lightweight. Therefore, we chose to use carbon fiber composites for the chassis, the battery boxes and the aerodynamic shell. At the same time, these three parts required a different production approach, depending on their respective specifications.
Carbon fiber prepreg for limited production runs is usually laid by hand, making it a labor intensive process, also careful attention is required to avoid the wrong orientation of the plies. Luckily, we had the opportunity to reduce the manual workload and the risks for the production of the chassis. Namely, the team made use of one of the newest carbon fiber processing technologies: Automated Tape Lay-up (ATL). This technique uses a robot performing the task of the worker: it lays down the plies in the correct orientation with a high accuracy and high speed. Nevertheless, using the ATL machine requires a different design approach than hand lay-up. More specifically, it makes use of unidirectional fibers instead of woven fibers. Also, the size of the carbon unidirectional tape roll is customized to the ATL machine. This is where Toray Advanced Composites came into play. Toray is a leading supplier of high quality carbon fiber composite materials which provides us with superb unidirectional fibers slit to the correct size. This makes it possible to create our lightweight skin-stiffened chassis with the highest accuracy.
Our second structural component, battery boxes, were produced with carbon fiber composite materials. As these boxes have a more complex shape than the chassis, the material selection was for woven carbon fiber composites rather than unidirectional fiber tapes, and the production process was done by hand lay-up. Toray offers the most comprehensive range and best quality carbon fibers currently on the market. Particularly, Toray Advanced Composites manufactures composite materials with a very high fiber content, resulting in strong, lightweight battery boxes.
The third structural component of our pod is the aerodynamic shell: this allows the pod to acquire a slender shape, reducing the air resistance during the final run. The shape of the aerodynamic shell includes various double curvatures. Therefore, hand manufacturing with pre-impregnated carbon fibers (prepregs) was not feasible. For this application, we selected unimpregnated Toray carbon fiber: these were laid into a mold and then injected with resin. The utilization of these fibers does not only allow for maximum strength at low weight, but also for agility in manufacturing.
We would like to thank Toray Advanced Composites for this fruitful collaboration.