非融合人工椎体疲劳实验与有限元仿真

发布时间：2018-05-01 09:00

本文选题：人工椎体 + 非融合技术　；参考：《天津理工大学》2017年硕士论文

【摘要】：近年来,腰椎间盘突出、肿瘤和暴力外伤等导致腰椎病变受损的疾病成为生活中常见病,患者腰椎正常的生理活动受限。目前重建病变腰椎生理功能和力学特性的方法主要是采用脊柱融合技术,脊柱融合技术虽然能够重建病变椎体的生理结构,却并不能恢复椎体骨原有的活动度。为此课题组以脊柱生物力学与材料学为依据设计了一种新型非融合技术人工椎体,在患者使用此非融合人工椎体置换后重建了原有脊柱结构的同时维持了一定的相邻椎体骨节段间活动度;人工椎体在植入人体后长时间受到人体的轴向压缩、扭转与侧向弯曲、前后屈曲等力的交互作用,有必要对设计出的人工椎体进行力学实验与有限元仿真。利用万能拉压电子试验机对人工椎体样件进行轴向压缩疲劳试验,采用500万次2 Hz 0.3 KN的正弦轴向压力对其进行疲劳实验,观察其疲劳特性,在疲劳实验开始时及每经过100万次疲劳载荷试验后对人工椎体样件进行轴向压缩实验,以测量其刚度变化;疲劳实验前后对人工椎体样件进行超声波清洗,用电子称来检测其植入人体后的材料磨损量。利用微控扭转试验机进行扭转实验,测量人工椎体与人工椎间盘的扭转角度与扭矩的关系;利用逆向工程技术建立了一种新型非融合人工椎体的植入人体后的有限元置换模型,在Ansys Workbench分析其植入人体后的应力与疲劳寿命分布,为投入临床应用提供数据参考。由钛合金托板、立柱与医用硅胶髓核组装而成的人工椎体的结构合理,在轴向压缩、扭转试验中,人工椎体与原置换组织的运动范围与力学性能相仿;人工椎体样件在200~300万次轴向疲劳载荷作用后,轴向压缩性能趋于稳定;500万次疲劳试验后,没有出现裂纹破坏等失效,材料间磨损量小,减少了异物进入内环境对健康造成危害,应力远低于其屈服强度;有限元仿真显示人工椎体置换模型应力分布均匀,疲劳分析显示其有着较高的疲劳寿命。此非融合人工椎体结构设计合理,植入人体能够恢复椎体间原有的活动度,对临近节段生物力学性能影响不大,能够满足长期植入人体的要求。
[Abstract]:In recent years, lumbar disc herniation, tumor and violent trauma have become common diseases in life, and the normal physiological activities of lumbar vertebrae are limited. At present, the main method to reconstruct the physiological function and mechanical properties of the lumbar vertebrae is the spinal fusion technique. Although the spinal fusion technique can reconstruct the physiological structure of the diseased vertebral body, it can not restore the original motion of the vertebral body bone. Based on the biomechanics and material science of the spine, a new non-fusion technique for artificial vertebrae was designed. After using this nonfused artificial vertebral body replacement, the patient reconstructed the original spinal structure while maintaining a certain degree of intersegmental activity of the adjacent vertebrae. The artificial vertebral body was subjected to axial compression, torsion and lateral bending of the human body for a long time after implantation. It is necessary to carry out mechanical experiments and finite element simulation for the designed artificial vertebrae due to the interaction of the equal forces of anterior and posterior buckling. The axial compression fatigue test of artificial vertebrae samples was carried out by using the universal tensile and compression electronic testing machine. The fatigue characteristics of the specimens were observed by using 5 million times of sinusoidal pressure of 2 Hz 0.3KN. At the beginning of fatigue experiment and after 1 million fatigue load tests, axial compression experiments were carried out to measure the stiffness of artificial vertebrae, and ultrasonic cleaning was carried out before and after fatigue test. Electronic weighing is used to measure the material wear after implantation. The relationship between torsion angle and torque of artificial vertebral body and artificial intervertebral disc was measured by micro-controlled torsion test machine, and a new finite element replacement model of artificial vertebral body was established by reverse engineering. The distribution of stress and fatigue life after implantation was analyzed by Ansys Workbench, which provides a data reference for clinical application. The artificial vertebral body composed of titanium alloy supporting plate, column and medical silica gel nucleus is reasonable. In the axial compression and torsion test, the movement range and mechanical properties of the artificial vertebral body and the original replacement tissue are similar. After 200 ~ 3 million axial fatigue loads, the axial compression properties of the artificial vertebral specimens tend to be stable, and after 5 million fatigue tests, there is no failure such as crack failure, and the wear amount between materials is small, which reduces the harm to health caused by the entry of foreign bodies into the inner environment. The stress is far lower than its yield strength, and the finite element simulation shows that the stress distribution of the artificial vertebral replacement model is uniform, and the fatigue analysis shows that the artificial vertebral replacement model has a high fatigue life. The non-fusion artificial vertebrae structure is designed reasonably, the implanted human body can restore the original range of motion between the vertebrae, and has little effect on the biomechanical properties of the adjacent segments, which can meet the requirements of long-term implantation of the human body.
【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】：R687.3;R318.1

【相似文献】