人工关节凝胶软骨材料的动态破坏研究

Dynamic response of cartilage repair hydrogel material

目的研究人工关节凝胶软骨材料在高应变率下的特性,探讨该材料应用于膝关节修补的可行性。方法通过霍普金森压力杆(SHPB)技术的应用,来研究凝胶材料在高应变率下的破坏情形。结果凝胶在冲击应变率达到1200 s-1时,凝胶并无任何破坏发生;当应变率为2000 s-1时,凝胶中心开始出现裂缝;达到3000 s-1时,凝胶中心部分已完全破裂了。结论未膨胀的凝胶可承受20 MPa的瞬间压应力而不会发生破坏,所以凝胶用来作为软骨的修补材料是十分有潜力的。

Objective To study the mechanical properties of the hydrogels under high strain rate. Methods In this study, modified Split Hopkinson Pressure Bar （SHPB） was utilized to measure the mechanical properties of the hydrogels under impact. SHPB techniques are the most commonly used method for determining material properties at high strain rates. The resultant volume ratio vs. pressure curve can best describe the compressibility of hydrogels under dynamic deformations. Results When hydrostatic strain rate reached 1200 s^-1, the hydrogels did not form any drastic damage. However, when hydrostatic strain rate reached 2000 s ^-1, the center of hydrogels started to cracks. When hydrostatic strain rate further increased to 3000 s^-1, the hydrogels has cracks all over the specimens and some shear bands could be observe clearly. Conclusions The hydrogels are super absorbents, it is also a bio-compatible material which has been considered as one of the most probable replacements for human soft tissues. Experimental results showed that the hydrogels also possess good mechanical strength for human joint cartilage repair.