Résumé
Objective To study the effect from the content change in hydroxyapatite (HA) on mechanical properties of polyvinyl alcohol/hydroxyapatite(PVA/HA)composite hydrogel and its load bearing characteristics based on experiment and finite element simulation. Methods The compression and stress relaxation tests of PVA/HA composite hydrogel were performed on the UMT test machine. Through the simulation and experimental results, the load-bearing characteristics of PVA/HA composite hydrogel and the effect of HA on PVA/HA composite hydrogel performance were investigated. Results With HA content increasing, the compression modulus of PVA/HA composite hydrogel was first increased and then decreased, while its permeability coefficient was first decreased and then increased. When the HA content was 3%，the compression modulus of PVA/HA composite hy drogel reached maximum (1.25 MPa)and its permeability coefficient reached minimum(1.59×10-3 mm4•N-1•s-1). The fluid bearing proportion of PVA/HA composite hydrogel was first increased and then decreased with the loading time increasing, which presented a nonlinear change. The proportion of the fluid bearing was significantly increased after HA added into PVA / HA composite hydrogel. The stress relaxation rate was first increased and then decreased with HA content increasing. Under the same loaded displacement, PVA / HA composite hydrogel with 3% HA content could disperse more contact stress. Conclusions The internal bearing characteristics of PVA / HA composite hydrogel have a great impact on its mechanical properties. When the HA content is 3%, the PVA / HA composite hydrogel has the best mechanical properties, which are closer to those of the natural articular cartilage.