缺损软骨受滚压载荷的实验设计与研究

发布时间：2019-01-01 18:07

【摘要】：关节软骨是人体关节的重要组成部分,参与人体大部分的行为活动,其中膝关节软骨在人体承重、减震中又起到了关键作用。但由于软骨特殊的结构特点,软骨内部没有血液供应营养物质,一旦受到损伤很难自我恢复,因此对软骨受损后的研究至关重要,深入研究更能够为骨关节炎患者提供更好的保养及恢复帮助。本课题主要是通过实验手段去深入研究缺损软骨在滚压载荷下的力学性能,分析总结软骨损伤演化规律,一方面通过实验数据去总结缺损对软骨的影响与伤口附近的力学性能,另一方面通过计算机仿真缺损软骨在滚压载荷下的应力、应变分布,验证实验结果的可靠性,为骨关节炎等临床软骨疾病提供参考依据。实验装置是软骨实验的重要组成部分,会影响到软骨实验的准确性。现针对缺损软骨需要进行的实验研究方案,设计了一套滚压加载实验装置,该装置主要由步进电机、连接杆、不锈钢压头、水槽、恒温加热装置组成。步进电机带动丝杠将回转运动转化为直线运动,通过连接杆带动压头做匀速往复滚动对软骨试件施加载荷。该装置可以在实验过程中提供恒温液态环境,模拟软骨在生物体内工作环境。该装置分别通过对软骨施加不同参数的滚压载荷,探索软骨在各载荷参数下的力学性能。采用非接触数字相关技术,实验记录分析缺损软骨在连续滚压载荷下伤口附近的应变变化情况,分析总结缺损软骨伤口附近的力学性能。实验结果表明缺损对软骨的力学性能有着一定影响,且随着损伤深度的增加,软骨表层点应变逐渐增加,中、深层点应变逐渐降低,其中切应变是主要破坏因素,软骨优先在缺口底角处破坏;随着滚压速率增加,缺损软骨浅表层应变先增加后降低,而在深层软骨应变呈增加趋势。将计算机有限元仿真结果与实验结果作对比可以看出,仿真曲线较实验曲线更平缓,曲线分布连续性更强,但由于不同软骨试件具有差异性,两曲线数值大小有差异,总体趋势与实验曲线保持一致,从而验证了实验的准确性与可靠性。
[Abstract]:Articular cartilage is an important part of human joint, which takes part in most of human behavior, in which articular cartilage plays a key role in bearing weight and reducing earthquake. However, due to the special structural characteristics of cartilage, there is no blood supply of nutrients in cartilage. Once damaged, it is difficult to recover itself, so it is very important to study the damage of cartilage. Further research can provide better maintenance and recovery for patients with osteoarthritis. The main purpose of this paper is to study the mechanical properties of defect cartilage under rolling load by experimental means, and to analyze and summarize the law of cartilage damage evolution. On the one hand, the influence of defect on cartilage and the mechanical properties near the wound are summarized through experimental data. On the other hand, the distribution of stress and strain of defective cartilage under rolling load is simulated by computer to verify the reliability of the experimental results, which provides a reference for clinical cartilage diseases such as osteoarthritis. Experimental device is an important part of cartilage experiment, which will affect the accuracy of cartilage experiment. In this paper, a rolling loading experimental device is designed, which is composed of stepping motor, connecting rod, stainless steel head, flume and constant temperature heating device. The stepper motor drives the lead screw to transform the rotary motion into the linear motion, and loads the cartilage specimen by using the connecting rod to drive the pressure head to make a uniform reciprocating roll on the cartilage specimen. The device can provide constant temperature liquid environment and simulate cartilage working environment in vivo. The mechanical properties of cartilage under different loading parameters were investigated by applying rolling load with different parameters. Non-contact digital correlation technique was used to record and analyze the strain changes of the defect cartilage near the wound under continuous rolling loading and the mechanical properties near the defect cartilage wound were analyzed and summarized. The experimental results show that the defect has a certain effect on the mechanical properties of cartilage, and with the increase of the depth of injury, the point strain of the surface layer increases gradually, and the point strain of the middle and deep layer decreases gradually, among which the shear strain is the main failure factor. The cartilage was destroyed at the bottom corner of the notch. With the increase of rolling rate, the strain of superficial surface layer of defect cartilage firstly increased and then decreased, but the strain of deep layer cartilage increased. Comparing the computer finite element simulation results with the experimental results, it can be seen that the simulation curve is more gentle than the experimental curve, and the continuity of curve distribution is stronger, but because of the difference of different cartilage specimen, the numerical value of the two curves is different. The overall trend is consistent with the experimental curve, which verifies the accuracy and reliability of the experiment.
【学位授予单位】：天津理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R681.3;R318.01

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