Experiment Design And Research Of Defect Cartilage Under Rolling Load

Articular cartilage is an important part of human joints,most activities involved in the human body activities,including knee cartilage in the human body load-bearing,shock absorption has played a key role.However,because of the special structural features of cartilage,there is no blood supply of nutrients within the cartilage,so the damage is difficult to self-recovery,and the cartilage damage after the study is essential,the study can provide better maintenance of osteoarthritis patients and recovery assistance.On the one hand,through the experimental data to sum up the impact of defects on the cartilage and mechanical properties near the wound,on the other hand,the cartilage damage in the cartilage damage and the mechanical properties of the cartilage damage,on the other hand,The stress and strain distribution of the defect cartilage under the rolling load was simulated by computer.It provided the reference for the clinical cartilage diseases such as osteoarthritis.Experimental device is an important part of cartilage experiments that can affect the accuracy of cartilage experiments.In this paper,a set of rolling loading experimental device is designed for the experimental study program of defective cartilage.The device is mainly composed of stepping motor,connecting rod,stainless steel indenter,container and constant temperature heating device.Stepper motor drive screw will be rotary motion into a linear motion,through the connecting rod to drive the indenter to do the uniform rolling to the cartilage specimen to load.The device can provide a constant temperature liquid environment during the experiment to simulate the environment of the cartilage in the organism.The device was designed by applying loads by different parameters to the cartilage,to measure the mechanical properties of the cartilage under the load.The non-contact digital correlation technique was used to analyze the strain changes of the defect cartilage near the defect under continuous rolling load,and the mechanical properties near the defect cartilage were analyzed and summarized.The experimental results showed that the defect had a certain effect on the mechanical properties of cartilage,and with the increase of the depth of injury,the strain of the cartilage surface gradually increased,and the strain of middle and deep point gradually decreased,in which the shear strain was the main destructive factor,and the cartilage preferentially destroyed at the corner of the defect.With the increase of rolling rate,the superficial strain first increased and then decreased,while the deep cartilage strain increased.Comparing the results of computer finite element simulation with the experimental results,it can be seen that the simulation curve is more gentle than the experimental curve,the curve distribution is stronger and the overall trend is consistent with the experimental curve.However,due to the differences in the different cartilage specimens,the numerical values of the two curves are different,but the general trend is similar,which verifies the accuracy and reliability of the experiment.