修复的缺损软骨在滑动条件下力学性质的研究

发布时间：2018-03-04 16:16

本文选题：缺损关节软骨　切入点：组织工程修复　出处：《天津理工大学》2014年硕士论文　论文类型：学位论文

【摘要】：关节软骨损伤和退化是日常生活中常见疾病，由于关节软骨处没有血液供应，损伤后很难实现自我修复。另外软骨损伤会导致患者在运动时有疼痛感，损伤程度过大还会使关节致残，带来极大痛苦。随着组织工程技术在软骨修复领域的逐步发展，损伤软骨的治愈率得到了大幅提升。但是目前组织工程构建的人工软骨组织对于缺损区域的修复效果有很大的不确定性，这与人工软骨性能和修复区的力学环境都是紧密相关的。适当的力学刺激有助于软骨组织的生长，过大则会使修复区应力分布不均，造成二次损伤。因此，探讨修复区域软骨对于力学环境变化的响应是非常重要的。本文以膝关节处存在的滑动作为加载方式，借助有限元仿真软件及数字图像相关技术，，对不同力学环境下修复区域软骨的力学性能进行了对比分析。主要内容及结果如下：建立修复后的全层缺损滑动加载模型。结合软骨的生理结构，在宿主软骨（天然软骨）处采用了纤维增强的固液双相材料。利用分层结构体现软骨弹性模量随深度变化的性能；借助ABAQUS子程序和FORTRAN语言的嵌套，实现依应变变化的渗透率；通过在节点添加弹簧单元模拟天然软骨中纤维的抗拉伸功能。对于人工软骨，采用了各向同性的均质材料，并假设人工软骨与宿主软骨接合良好。分别探讨了滑动压缩量、滑动速度及人工软骨弹性模量的改变对于修复区域应力、孔隙压力、接触应力及Y向应变的影响规律。结果表明：在滑动这一动态载荷下，软骨受力主要由孔隙压力承担。滑动过程中，滑块所处位置对于修复区的力学性能影响较大，当滑块作用在接合面处时，会出现较大的应变及应力。压缩量的增大会加大人工软骨及宿主软骨的受力及变形，特别是接合面处的变形大幅增加。人工软骨弹性模量增大可提高承载能力，适当的模量值可减少接合面处的应力集中。滑动速度增加时，滑块和软骨间接触时间缩短，变形量减小，但对于接合面会造成较大的冲击。对修复后的全层缺损软骨进行滑动加载实验，结合数字相关技术对图像进行了数据处理，探讨滑动压缩量及滑动速度两个方面对于修复区域应变分布的影响。通过滑动实验中宿主软骨处Y向应变值验证模型中宿主软骨材料参数的正确性。改变滑动压缩量及滑动速度均会对修复区域产生一定影响，并且通过对不同层区的比较，发现表层变化趋势最为明显。本文从实验和仿真两方面对修复区域软骨性能进行研究，使得结果更为全面，为关节软骨临床疾病的预防与治疗提供了一定的理论依据。
[Abstract]:Articular cartilage injury and degeneration are common diseases in daily life. Because there is no blood supply in articular cartilage, it is difficult to self-repair after injury. Too much damage can also cripple joints and cause great pain. With the gradual development of tissue engineering technology in the field of cartilage repair, The cure rate of damaged cartilage has been greatly improved. However, there is much uncertainty about the effect of artificial cartilage tissue constructed by tissue engineering on the repair of defect area. This is closely related to the performance of the artificial cartilage and the mechanical environment of the repair zone. Proper mechanical stimulation contributes to the growth of the cartilage tissue, and excessive stress distribution in the repair zone results in secondary damage. It is very important to study the response of repaired regional cartilage to the change of mechanical environment. In this paper, with the help of finite element simulation software and digital image correlation technology, the mechanical properties of the cartilage repaired in different mechanical environments are compared and analyzed with the help of the sliding in the knee joint. The main contents and results are as follows:. To establish a sliding loading model of full-thickness defect after repair, combined with the physiological structure of cartilage, Fiber reinforced solid / liquid biphasic material was used in the host cartilage (natural cartilage). The layered structure was used to reflect the property of the elastic modulus of cartilage varying with the depth, and the permeability varied according to strain was realized by the nesting of ABAQUS subroutine and FORTRAN language. The tensile resistance of fibers in natural cartilage was simulated by adding spring element to the node. For artificial cartilage, isotropic homogeneous material was used, and the artificial cartilage bonded well with host cartilage. The effects of sliding velocity and elastic modulus of artificial cartilage on the stress, pore pressure, contact stress and Y-direction strain in the repaired region are studied. During the sliding process, the position of the slider has a great influence on the mechanical properties of the repair area, when the slider acts on the joint, Larger strain and stress will occur. The increase of compression will increase the stress and deformation of artificial cartilage and host cartilage, especially the deformation of joint surface. The increase of elastic modulus of artificial cartilage can increase the bearing capacity of artificial cartilage. When the sliding velocity increases, the contact time between the slider and the cartilage decreases, but the deformation decreases. The full-thickness defect cartilage was subjected to sliding loading experiment and digital correlation technology was used to process the image. The effects of sliding compression and sliding velocity on the strain distribution in the repair region were discussed. The parameters of the host cartilage were verified by Y-direction strain values of the host cartilage in the sliding experiment, and the sliding pressure was changed. Shrinkage and sliding speed will have a certain impact on the repair area, And through the comparison of different layers, it is found that the change trend of surface layer is the most obvious. In this paper, the performance of repaired regional cartilage is studied from two aspects of experiment and simulation, which makes the results more comprehensive and provides a certain theoretical basis for the prevention and treatment of articular cartilage clinical diseases.
【学位授予单位】：天津理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：R318.01

【相似文献】