腰5椎体指数的减小对其峡部应力影响的有限元分析

发布时间：2018-06-12 14:55

本文选题：腰5椎体指数 + 有限元模型　；参考：《南华大学》2015年硕士论文

【摘要】：目的:通过建立2个无腰椎疾患的成人腰5椎体三维有限元模型,并对2个有限元模型进行有效性验证,探讨腰5椎体指数的减小,与其峡部的应力关系。方法:采集2个无腰椎疾患的成人腰5椎体,其指数分别为70、90的CT数据。通过mimics10.0软件分离重建单个腰5椎体几何模型,将重建的模型导入geomagic11.0使粗糙的几何模型进行光滑等优化处理并生成曲面模型,再将曲面模型导入UGS NX6.0软件进行缝合处理,生成实体模型。将实体模型导入ansys14.0有限元软件,通过布尔运算将模型划分为皮质骨与松质骨,再将腰5椎体的皮质骨与松质骨进行粘合,并对模型赋予单元类型及材料属性,再将实体模型进行有限元网格划分,对网格划分成功的腰5椎体有限元模型的下表面及下关节突的所有节点,在各个方向的自由度施加约束,以及对腰5椎体上表面和上关节突的所有节点逐步递增施加轴向载荷,通过有限元软件的后处理功能对腰5椎体峡部进行应力分析并计算有限元模型的位移。用Spss19.0软件统计两个模型双侧峡部的应力值,比较其差异性。结果:1.腰5椎体指数为70的有限元模型单元数47147个,节点数71601个,腰5椎体指数为90的有限元模型单元数37895个,节点数57646个。通过对模型逐步递增施加载荷,其压缩-位移数据在国外文献报道的体外实验数据的范围之间。2.在500N的作用力下,对照组峡部应力值1.04±0.12,参照组峡部应力值2.03±0.10,两组对比(P0.05)。在1000N的作用力下,对照组峡部应力值2.30±0.22,参照组峡部应力值3.29±0.34,两组对比(P0.05)。在1500N的作用力下,对照组峡部应力值4.05±0.28,参照组峡部应力值4.81±0.55,两组对比(P0.05)。在2000N的作用力下,对照组峡部应力值6.85±0.52,参照组峡部应力值9.07±0.54,两组对比(P0.05)。对照组及观察组的峡部应力值分别在500N、1000N、1500N、2000N之间比较有差异(P0.05)。结论:1.成功建立了2个腰5椎体指数分别为70、90的有限元模型,并验证了两个椎体指数分别为70、90的有限元模型的有效性。2.椎体指数小的腰5峡部所承受的应力要大于椎体指数大的腰5峡部所承受的应力。并且随着载荷的增大,双侧峡部的应力也随之增大。若腰5椎体指数较小的峡部长期处于高负荷状态下,其腰5峡部可能更容易出现崩裂。
[Abstract]:Objective: to establish two three dimensional finite element models of lumbar 5 vertebrae in adults without lumbar disease, and to verify the validity of the two finite element models, and to explore the relationship between the decrease of lumbar 5 vertebral body index and the stress in the isthmus. Methods: the CT data of lumbar 5 vertebrae of 2 adults without lumbar disease were 70 ~ 90 respectively. A single lumbar 5 vertebrae geometry model was reconstructed by mimics10.0 software. The reconstructed model was imported into geomagic11.0 to make rough geometry model smooth and optimized, and the surface model was generated. The surface model was imported into UGS NX6.0 software for suture. Generate entity model. The solid model was imported into ansys14.0 finite element software. The model was divided into cortical bone and cancellous bone by Boolean operation. The cortical bone and cancellous bone of lumbar 5 vertebrae were bonded to each other, and the unit type and material attribute were assigned to the model. Then the solid model is meshed by finite element method, and all the nodes of the lower surface and the lower articular process of the lumbar 5 vertebrae finite element model, which are successfully meshed, are constrained by the degrees of freedom in all directions. The axial load on the upper surface of the lumbar 5 vertebra and all the nodes of the upper articular process is gradually applied. The stress of the isthmus of the lumbar 5 vertebrae is analyzed and the displacement of the finite element model is calculated by the post processing function of the finite element software. The stress values of bilateral isthmus of the two models were calculated by Spss19.0 software and the differences were compared. The result is 1: 1. The finite element number of lumbar 5 vertebral body index is 70, the number of finite element model is 47147, the number of nodes is 71601, the finite element number of lumbar 5 vertebral body index is 90 and the number of finite element model is 37895 and the number of nodes is 57646. By gradually increasing the load on the model, the compression-displacement data between the range of in vitro experimental data reported in foreign literature. The stress of isthmus in the control group was 1.04 卤0.12, and that in the control group was 2.03 卤0.10 under the action force of 500N. The isthmus stress of the control group was 2.30 卤0.22, and that of the control group was 3.29 卤0.34. The stress of isthmus in the control group was 4.05 卤0.28, that in the control group was 4.81 卤0.55, and that in the control group was 4.81 卤0.55. The stress of isthmus in the control group was 6.85 卤0.52, and that in the control group was 9.07 卤0.54, which was compared with that in the control group (P 0.05). The stress values of isthmus in the control group and the observation group were significantly different from those in the control group and the observation group respectively between 500 Nu 1000N and 1500 Nu 2000N (P 0.05). Conclusion 1. Two finite element models with L5 vertebral body index of 70 ~ 90 were successfully established, and the validity of two finite element models with L5 vertebral body index of 70 ~ 90 was verified. The stress of the lumbar 5 isthmus with small vertebral body index is greater than that of the lumbar 5 isthmus with large vertebral body index. And with the increase of load, the stress of bilateral isthmus also increases. If the isthmus with low lumbar 5 body mass index is in high load for a long time, the lumbar 5 isthmus may be more prone to collapse.
【学位授予单位】：南华大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：R687.3

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