Various reinforcements of the C/C composite bone plates and their influence on mechanical properties

Carbon-carbon composite plates with three different reinforcement styles were manufactured and tested for mechanical properties and biocompatibility in view of their application as implants in bone surgery. Their stress state under load on bending was simulated by the Finite Element Method. The shape of the plates was designed to match the pig femur. The reinforcement was made of plain-weave carbon fabric lamina by stacking, coiling, or combination of both. Phenolic resin was used both as a precursor of the rnatrix and an impregnant. After final heat treatment at 2200°C a layer of pyrolytic carbon was deposited to reduce the formation of carbon particles. The plates with combined reinforcement yielded higher bending strength and lower stiffness on bending than those of human bones. Biocompatibility of the material was tested using "in vitro" and "in vivo" tests. The FEM stress distribution simulation yielded a good agreement of the failure location and bending strength value with the experimental data.