Optimization of mass-produced trans-tibial prosthesis made of pultruded fiber reinforced plastic

Saito et al. [Mod. Plast. (1997) 175–177] have developed a low-cost transtibial prosthesis made of fiber reinforced plastic (FRP). The basic design of the prosthesis consists of an aluminum pylon, constant crosssection composite foot, and cosmetic cover. Aluminum supports are screwed into the foot section to increase the load bearing capacity. Replacing these supports with a single integrated FRP stiffener significantly reduce the cost of manufacturing while allowing for high strength, great durability, and smooth walking. Using FE analysis, the optimal location and orientation of the FRP stiffener were determined. The optimized model has a maximum Mises stress and shear stress of 56.3 and 3.6 MPa respectively for a load of 1000 N. Failure of the prosthesis was predicted to occur at a load of 5200 N which fully satisfies the ISO standard 10328 for prosthesis.