Benefits of Carbon Composite

UWashington Hyperloop Shell Stress Test

What are the benefits to using composite over other materials?

Weight Savings: Composites provide the greatest strength per pound yield in the industry (that are commercially available to the majority of consumers). In the case of the Hyperloop pod, weight savings equates to less power required (in terms of propulsion).

Aerodynamics/Manufacturability: There is a lot of speculation that composites are generally more difficult to manufacture than metals. While that may be true for simplistic designs, composite parts are far easier to manufacture for complex contours than metals. For our current shell design, it would be impossible to contour a metallic sheet in this fashion without altering the design.

Corrosion and Fatigue Resistance: It is known that carbon fiber materials are some of the most cathodic materials in existence in that they are nearly impossible to corrode. For the Hyperloop concept, corrosion resistance would result in less maintenance issues. On the same note, the fatigue resistance of carbon composites is highly desirable to minimize required maintenance.

Is carbon composite difficult to work with / manufacture?

The short answer is yes, the process is long and there are many steps. However, given our design (complex contours included), I firmly believe that a carbon fiber cloth with wet layup application is the easiest method of fabrication.

Steps would begin with fabricating foam or composite tooling as a layup surface. This surface would require a vast amount of prep work. The next step would be laying up the desired ply design, which would be repeated for every ply needed at various angles required. Given our current design, there would be eight plies surrounding the shell, and another 24 plies sandwiched in between at specific areas surrounding holes. The layup would then require a cure cycle and after all of that, we’d have to remove the part from the mold and trim off any excess fibers in addition to any necessary reaming for the holes. Note that this process would be vastly more difficult with pre-preg material for the laying up portion. Pre-preg material is much stiffer due to the built in resin system and is much harder to lay on surfaces (especially in tight and complex contours).

Do you see carbon composite replacing other materials in the future?

Yes, as an aerospace/mechanical engineer, we are already seeing that heavily in industry today. In aviation, the weight savings characteristic of carbon equates to less fuel consumption for customers, which is highly sought after in that market. The corrosion and fatigue resistance capabilities are obviously big drivers for designing with composites over metals.

What do see as a major design difference between our pod vs. the competition?

As far as the shell design goes, other shells that have been fabricated (such as for MIT) are significantly less complex in terms of contour. I am hoping that our Aerodynamic efficiency is superior as a result.