Design Criteria
1) Durable
- Can withstand different terrains (track, sand, grass, pavement, etc.)
- Must be able to support the user
PAN/graphene-based carbon fiber vs. PAN-based carbon fiber
- They both have similar mechanical properties [17].
- PAN/graphene-composite carbon fiber has overall higher/stronger material and structural properties [17]
2) Low Cost
- Prosthetics do not last forever
- Current running blade material solution:
PAN-based carbon fibers (current solution material)
- Costs $15 per pound to manufacture [18]
- Is 10X cost of steel [17]
Using a PAN/graphene-composite carbon fiber is more cost-effective.
3) Catered to User
Use soft, compressible materials for coupling, for example:
- Silicone gel → Can withstand mechanical stress [19]
- Foam → Shock absorption [20]
- Elastomer → Similar to rubber in elasticity [20]
- 3D spacer fabric → Can withstand thousands of repeated loadings [21]
Replicates biological limbs
- Biological ankle has 241% energy return [22]
- Current solutions only return 63%-95% of energy [11]
References
[17]: Gao, Z., et al., Graphene reinforced carbon fibers. Sci Adv, 2020. 6(17): p. Eaaz4191.
[18]: Jackson, L. Graphene-reinforced carbon fiber may lead to affordable, stronger car materials. May 18, 2020; Available from: https://news.psu.edu/story/620332/2020/05/18/research/graphene-reinforced-carbon-fiber-may-lead-affordable-stronger-car.
[19]: Sanders, J.E., et al., Testing of elastomeric liners used in limb prosthetics: Classification of 15 products by mechanical performance. Journal of Rehabilitation Research & Development, 2004. 41(2): p. 175-185.
[20]: Li, J., W.-Y. Wong, and X.-m. Tao, Recent advances in soft functional materials: preparation, functions and applications. Nanoscale, 2020. 12(3): p. 1281-1306.
[21]: Mazari, F.B., et al., Comparison of different interlining materials of car seat cover under repeated loadings. Industria Textila, 2020. 71(3): p. 199-203.
[22]: Noroozi, S., et al., Modal analysis of composite prosthetic energy-storing-and-returning feet: an initial investigation. Proceedings of the Institution of Mechanical Engineers, Part P: Journal of Sports Engineering and Technology, 2013. 227(1): p. 39-48.
[11]: Beck, O.N., P. Taboga, and A.M. Grabowski, Characterizing the Mechanical Properties of Running-Specific Prostheses. PloS one, 2016. 11(12): p. e0168298.