Department of Mechanics of Materials and Structures, Faculty of Civil and Environmental Engineering, Gdańsk University of Technology, Gdańsk, Pomerania, Poland.
2nd Division of Orthopedics & Kinetic Organ Traumatology, Faculty of Medicine, Medical University of Gdańsk, Gdańsk, Pomerania, Poland.
PeerJ. 2023 Aug 11;11:e15805. doi: 10.7717/peerj.15805. eCollection 2023.
The functional biomechanics of the lumbar spine have been better understood by finite element method (FEM) simulations. However, there are still areas where the behavior of soft tissues can be better modeled or described in a different way. The purpose of this research is to develop and validate a lumbar spine section intended for biomechanical research. A FE model of the 50th percentile adult male (AM) Total Human Model for Safety (THUMS) v6.1 was used to implement the modifications. The main modifications were to apply orthotropic material properties and nonlinear stress-strain behavior for ligaments, hyperelastic material properties for annulus fibrosus and nucleus pulposus, and the specific content of collagenous fibers in the annulus fibrosus ground substance. Additionally, a separation of the nucleus pulposus from surrounding bones and tissues was implemented. The FE model was subjected to different loading modes, in which intervertebral rotations and disc pressures were calculated. Loading modes contained different forces and moments acting on the lumbar section: axial forces (compression and tension), shear forces, pure moments, and combined loading modes of axial forces and pure moments. The obtained ranges of motion from the modified numerical model agreed with experimental data for all loading modes. Moreover, intradiscal pressure validation for the modified model presented a good agreement with the data available from the literature. This study demonstrated the modifications of the THUMS v6.1 model and validated the obtained numerical results with existing literature in the sub-injurious range. By applying the proposed changes, it is possible to better model the behavior of the human lumbar section under various loads and moments.
有限元法（FEM）模拟使人们对腰椎的功能生物力学有了更好的理解。然而，在某些方面，软组织的行为仍然可以通过更好的建模或用不同的方式来描述。本研究的目的是开发和验证一个用于生物力学研究的腰椎节段。使用第 50 百分位成人男性（AM）全人体安全模型（THUMS）v6.1 的 FEM 模型来实现修改。主要的修改是为韧带应用各向异性材料特性和非线性应力-应变行为，为纤维环和核髓施加超弹性材料特性，以及纤维环基质中胶原纤维的特定含量。此外，还实现了核髓从周围骨骼和组织的分离。FE 模型经受了不同的加载模式，其中计算了椎间旋转和椎间盘压力。加载模式包含作用于腰椎节段的不同力和力矩：轴向力（压缩和拉伸）、剪切力、纯力矩以及轴向力和纯力矩的组合加载模式。从修改后的数值模型获得的运动范围与所有加载模式的实验数据一致。此外，修改后的模型的椎间盘内压力验证与文献中可用的数据吻合良好。本研究展示了 THUMS v6.1 模型的修改，并在亚损伤范围内用现有文献验证了获得的数值结果。通过应用所提出的更改，可以更好地模拟人体腰椎节段在各种载荷和力矩下的行为。
