The Investigation Of The Bio-tribological Properties Of Natural Swine Articular Cartilage

In this dissertation, the micro-morphology and structure were characterized by many experimental techniques such as SEM and FTIR. With constant vacuum temperature container of 40℃, the mass losses of pure cartilage, subchondral bone and cartilage sample were measured under different volatilization times, and accordingly volatilization times of different hydrated rates were gained. Tensile deformation of different hydrated rates was measured. A pin-on-disc friction and wear test apparatus was devised to investigate the bio-tribological properties of natural swine articular cartilage under various lubrication conditions, load, velocity, place and counterpart.The main results are as follows:1. The surface of cartilage was unsmooth, present ravine and ripple shape.The cartilage was parted as noncalcifled cartilage, calcified cartilage and subchondral bone three zones. The noncalcified cartilage zone was interlocked tightly in the manner of "ravine-engomphosis" by the calcified cartilage zone, and the subchondral bone was anchored tightly in the manner of "comb-anchor" by the in the calcified cartilage zone.2. These results showed that the mass losses of pure cartilage, subchondral bone and cartilage sample functioned with a non-linear ascended relation with volatilization time in the environmental temperature of 40℃. The volatilization time for different hydrated rates of 75%, 50%, 25% and 0 was 17min, 35min, 54min and 100min, respectively.3. The change behavior of tensile with the changes of strain shows a non-linear relationship. More hydrated rate produced more tensile deformation, more tensile modulus and strength. The viscoelastic mechanisms of flow-dependence and flow-independence were manifested by tensiled deformations. Tensile fracture of the articular cartilage was a ductile fracture, which was caused by the process of porous fibrous structure of the internal micro-cracks expanded and interconnected.4. The experimental results show that the friction coefficient and wear mass has descending order under dry friction, distilled water, physiological saline, bovine serum respectively. The friction coefficient and wear mass firstly increased and then tended to reduce with the increase of bovine serum content. Under the same working velocity, the friction coefficient increase with the increase of load. For the same working load, the higher the velocity, the lower the friction coefficient. The friction coefficient and wear mass of articular cartilage/articular cartilage was lower than articular cartilage/UHMWPE, which was lower than cartilage/stainless steel.The same articular cartilage which is at the head of the cartilage has the lowest friction coefficient. Away from the the head of the cartilage, the friction coefficient is higher.5. Under dry friction condition, the wear mechanisms were mainly fatigue wear, abrasive wear, there are many fatigued cracks on the worn surface. Under lubrication condition, the wear mechanisms were mainly adhesive wear, abrasive wear, microcosmic fatigue wear, there are less cracks on the worn surface. There are many fatigued cracks, concave and holes under dry friction. There are only a little grinded traces under bovine serum lubrication. Under different conditions, the worn surface morphology showed a positive correlation with the friction coefficient and wear mass under the corresponding conditions.