Background: Spine injury risk due to military conflict is an ongoing concern among defense organizations throughout the world. A better understanding of spine biomechanics could assist in developing protection devices to reduce injuries caused by caudocephalad acceleration (+Gz) in under-body blasts (UBB). Although some finite element (FE) human models have demonstrated reasonable lumbar spine biofidelity, they were either partial spine models or not validated for UBB-type loading modes at the lumbar functional spinal unit (FSU) level, thus limiting their ability to analyze UBB-associated occupant kinematics. Methods: An FE functional representation of the human spine with simplified geometry was developed to study the lumbar spine responses under +Gz loading. Fifty-seven load curves obtained from post mortem human subject experiments were used to optimize the model. Results: The model was cumulatively validated for compression, flexion, extension, and anterior-, posterior-, and lateral-shears of the lumbar spine and flexion and extension of the cervical spine. The thoracic spine was optimized for flexion and compression. The cumulative CORrelation and Analysis (CORA) rating for the lumbar spine was 0.766 and the cervical spine was 0.818; both surpassed the 0.7 objective goal. The model’s element size was confirmed as converged. Conclusions: An FE functional representation of the human spine was developed for +Gz lumbar load analysis. The lumbar and cervical spines were demonstrated to be quantitatively biofidelic to the FSU level for multi-directional loading and bending typically experienced in +Gz loading, filling the capability gap in current models.

背景：军事冲突导致的脊柱损伤风险是全世界国防组织持续关注的问题。更好地了解脊柱生物力学有助于开发保护装置，以减少由体下爆炸 (UBB) 中的头尾加速度 (+Gz) 造成的伤害。尽管一些有限元 (FE) 人体模型已经证明了合理的腰椎生物保真度，但它们要么是部分脊柱模型，要么未在腰椎功能性脊柱单元 (FSU) 水平上验证 UBB 型加载模式，因此限制了它们分析 UBB- 的能力。相关的乘员运动学。方法：开发了具有简化几何形状的人体脊柱 FE 功能表示，以研究 +Gz 负载下的腰椎反应。从验尸人体实验中获得的 57 条负载曲线用于优化模型。结果：该模型在腰椎的压缩、屈曲、伸展、前剪、后剪和侧剪以及颈椎的屈伸方面得到了累积验证。胸椎针对屈曲和压缩进行了优化。腰椎的累积相关性和分析 (CORA) 评分为 0.766，颈椎为 0.818；都超过了0.7的客观目标。模型的单元尺寸被确认为收敛。结论：为 +Gz 腰椎负荷分析开发了人类脊柱的 FE 功能表示。腰椎和颈椎被证明在数量上对 FSU 水平具有多向加载和弯曲的生物真实性，通常在 +Gz 加载中经历，填补了当前模型中的能力差距。