PVA /HA复合水凝胶力学性能分析及有限元模拟

目的通过实验与有限元模拟对羟基磷灰石(HA)改变聚乙烯醇/羟基磷灰石(PVA/HA)复合水凝胶的力学性能本质及其承载特性进行研究。方法在UMT试验机上进行PVA/HA复合水凝胶的压缩及应力松弛实验。通过模拟与实验结果相结合,研究PVA/HA复合水凝胶的承载特性及HA对其性能的影响。结果随着HA含量的增加,PVA/HA复合水凝胶的压缩模量先增大后减小,而渗透系数先减小后增大;HA含量为3%的PVA/HA复合水凝胶压缩模量最大、渗透系数最小,分别为1.25 MPa和1.59×10-3 mm4.N-1.s-1。PVA/HA复合水凝胶的液体承载比例随着施载时间的增加呈现先增加后减小的非线性变化,加入HA的PVA/HA复合水凝胶的液体承载比例明显增加。应力松弛速率随着HA含量增加呈先上升后下降趋势,下压相同位移HA,含量为3%时,PVA/HA复合水凝胶所能分散的应力更多。结论 PVA/HA复合水凝胶内部的承载特性影响着其力学性能,HA含量为3%时的PVA/HA复合水凝胶力学性能最优,更接近于天然关节软骨的力学性能。

Mechanical property analysis of PVA/HA composite hydrogel and its finite element simulation

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.