腰椎三维有限元模型建立和应力分析

目的 建立完整的腰椎三维有限元模型,并对腰3-4运动节段的进行了有效性验证和生物力学分析.方法 利用交互式医学图像控制系统MIMICS软件对CT图片进行预处理,后导人大型通用有限元软件ABAQUS中建立三维有限元模型.分别建立了腰1-腰5各椎体及其椎间盘有限元实体,后组合成整体的腰椎和腰3-4有限元模型,并且还准确的模拟了腰椎的椎间盘、软骨终板、关节突关节以及连接韧带.验证了模型的收敛性,并针对腰34运动单元设置了0.3、0.5、1.0、2.0、4.0 mPa 5种载荷进行生物力学分析.结果 在轴向压力作用下,椎间盘纤维环后部存在着明显的应力集中,并向后外侧传导.最大压应力的部位在髓核和软骨终板的中央,椎弓根是椎体多种应力集中的部位.轴向压力增加,应力成比例增大.结论 本研究的有限元模型精确度高,结论符合腰椎的临床特点,较好的模拟了腰椎的生物力学特性.

Finite element analysis on stress change of lumbar spine

Objective To build a 3D finite element model of whole lumbar spine and verify its efficiency and analyze tIle biomechanieal change of L3-4 motion segment.Methods L1-L5 segment data were obtained from computed tomography(CT)scans of the lumbar spine of a 40-year-old man with no abnormal findings.A three-dimensional finite element model of the human whole lumbar spine was built in the Mimics and the ABAQUS software.The model was composed of bony vertebrae,articulating facets,intervertebral disc and associated ligaments.The basic stress analysis of L3-4 motion segment was made under the considerations of different material properties of bone,ligaments and facet joints contacting frictional property.The stress on annulus fiber,nucleus pulposus,endplate and facet joints under axial pressure(0.3 MPa,0.5 MPa,1.0 MPa,2.0 MPa & 4.0 MPa)were analyzed.Results A threedimensional finite element model of human L3-L4 motion segment has 272,619 elements,the stresses were higher in the posterior of annulus fiber,the Max pressure stress(S33)distributed in nucleus pulposus and the center of endplate.The stresses increased a8 axial pressure rose.Conclusion 3D finite element model of whole lumbar spine and L3-4 motion segment were established successfully and the stress analyses were feasible and reliable.