关节软骨回弹力学性质实验研究及有限元仿真

发布时间：2018-05-07 09:46

本文选题：关节软骨 + 压缩回弹　；参考：《天津理工大学》2017年硕士论文

【摘要】：随着社会文明的发展,健康越来越被人们所追捧,健身运动已经成为人们生活中的一部分。但是大强度的运动很可能在不经意间造成软骨的损伤,尤其是在未经完全恢复的情况下再次运动。众所周知,关节软骨是缓冲关节负载、减小外力与关节的接触应力、降低关节运动时的摩擦、磨损的重要支撑组织。可以说关节软骨的健康是关节运动的必要条件。因此研究软骨回弹力学性质有一定的现实意义。在此之前,研究关节软骨的种类有很多,包括关节软骨的拉伸、压缩、缺损及关节软骨的棘轮效应等,但是对关节软骨回弹的研究还未见有相应的报道。本文主要是想探究:1.利用先进的非接触式拉压机,通过不同的加载方式进行实验。而后结合数字图像相关技术及后处理的相关技术来研究对不同加载载荷及时间对关节软骨回弹力学性能的影响。2.基于关节软骨内部的纤维结构及它的固—液二相性,结合以前实验得出的一些参数,运用ABAQUS有限元分析软件对关节软骨进行简化建模,模拟出关节软骨在不同载荷、不同持续压缩时间下的回弹仿真,然后得出关节软骨回弹仿真的相关力学性能。3.结合非线性粘弹性材料的本构模型,预测回弹规律,并与实验仿真结果相对比,得出较准确的结论。结果显示在不同载荷不同压缩时间下不同层区的软骨回弹性能是不尽相同的,但是回弹的趋势是有可比性的。回弹时软骨浅表层回弹的应变变化最快,深层区最小,各层区应变分别从20%、10%、6%左右降到3%所用的时间相似;回弹时间越长,软骨不同层区回弹的应变变化越缓慢,但最终各层区应变均会小于1%。相同层区不同压缩载荷作用下,在回弹初期,载荷越大,软骨回弹应变变化越快;在回弹后期,载荷越小,回弹应变变化越快。最终载荷小的更接近压缩前的状态。相同层区不同持续压缩时间和载荷的影响相似。另外在关节软骨的有限元仿真中也对软骨回弹仿真进行了和实验相同的加载方式。从对比结果来看:仿真结果和实验结果及理论推导得出了比较吻合的变化趋势。说明了本次研究具有一定的参考意义。结果表明软骨各个层区回弹状况与其各层区的结构是具有相关性的。从数据上看,关节软骨90%左右的回弹主要集中在前十五分钟左右。关节软骨不同层区的力学回弹性能与其加载载荷和加载持续时间都有密切的相关性。且压缩时间和压缩载荷具有相似的影响效果。载荷和压缩时间的增加都会对回弹产生不利的影响。从回弹后期数据说明经过一定的时间基本能回弹到压缩前的状态。
[Abstract]:With the development of social civilization, health is more and more sought after, fitness has become a part of people's life. But heavy exercise is likely to cause cartilage damage inadvertently, especially if it is not fully recovered. As we all know, articular cartilage is an important supporting tissue to buffer joint load, reduce contact stress between external force and joint, and reduce friction and wear during joint motion. It can be said that the health of articular cartilage is a necessary condition for joint movement. Therefore, it is of practical significance to study the mechanical properties of cartilage springback. Before this, there are many kinds of articular cartilage, including articular cartilage stretching, compression, defect and articular cartilage ratchet effect, but the research on articular cartilage springback has not been reported. The main purpose of this paper is to explore 1: 1. Using advanced non-contact drawing press, the experiment is carried out through different loading methods. Then the effects of different loading loads and time on the springback mechanical properties of articular cartilage were studied by combining digital image correlation and post-processing techniques. Based on the fiber structure of articular cartilage and its solid-liquid biphase, combined with some parameters obtained from previous experiments, the simplified modeling of articular cartilage was carried out by using ABAQUS finite element analysis software, and the different loads of articular cartilage were simulated. The springback simulation of articular cartilage with different sustained compression time was carried out, and the related mechanical properties of the springback simulation of articular cartilage were obtained. 3. Combined with the constitutive model of nonlinear viscoelastic materials, the springback law is predicted, and compared with the experimental results, a more accurate conclusion is obtained. The results show that the springback performance of cartilage in different layers is different under different loading and compression time, but the trend of springback is comparable. When springback occurs, the strain of the shallow surface of cartilage changes fastest, and that of the deep layer is the smallest, and the strain of each layer decreases from 106% to 3% respectively, and the longer the springback time is, the slower the strain changes in the different layers of cartilage. But the strain of each layer will be less than 1. Under the action of different compression loads in the same layer, in the initial springback stage, the greater the load, the faster the springback strain changes, and the smaller the load is, the faster the springback strain changes at the later springback stage. The final load is smaller and closer to the state before compression. The effect of different sustained compression time and load on the same layer is similar. In addition, in the finite element simulation of articular cartilage, the springback simulation of cartilage is carried out in the same way as the experiment. From the comparison results, the simulation results and experimental results, as well as theoretical derivation, show that the variation trend is consistent. It shows that this study has certain reference significance. The results show that the springback of each layer of cartilage is related to the structure of each layer of cartilage. From the data, articular cartilage about 90% of the rebound mainly concentrated in the first 15 minutes or so. The mechanical resilience of different layers of articular cartilage is closely related to the loading load and loading duration. The compression time and the compression load have similar effect. The increase of load and compression time will have a negative effect on springback. From the springback data show that after a certain period of time can basically rebound to the state before compression.
【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】：R873;R318.01

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