Validation of a booted finite element model of the WIAMan ATD lower limb in component and whole-body vertical loading impacts with an assessment of the boot influence model on response

<b>Objective</b>: A novel anthropomorphic test device (ATD) representative of the 50th percentile male soldier is being developed to predict injuries to a vehicle occupant during an underbody blast (UBB). The main objective of this study was to develop and validate a finite element (FE) model of the ATD lower limb outfitted with a military combat boot and to insert the validated lower limb into a model of the full ATD and simulate vertical loading experiments. <b>Methods</b>: A Belleville desert combat boot model was assigned contacts and material properties based on previous experiments. The boot model was fit to a previously developed model of the barefoot ATD. Validation was performed through 6 matched pair component tests conducted on the Vertically Accelerated Loads Transfer System (VALTS). The load transfer capabilities of the FE model were assessed along with the force-mitigating properties of the boot. The booted lower limb subassembly was then incorporated into a whole-body model of the ATD. Two whole-body VALTS experiments were simulated to evaluate lower limb performance in the whole body. <b>Results</b>: The lower limb model accurately predicted axial loads measured at heel, tibia, and knee load cells during matched pair component tests. Forces in booted simulations were compared to unbooted simulations and an amount of mitigation similar to that of experiments was observed. In a whole-body loading environment, the model kinematics match those recorded in experiments. The shape and magnitude of experimental force–time curves were accurately predicted by the model. Correlation between the experiments and simulations was backed up by high objective rating scores for all experiments. <b>Conclusion</b>: The booted lower limb model is accurate in its ability to articulate and transfer loads similar to the physical dummy in simulated underbody loading experiments. The performance of the model leads to the recommendation to use it appropriately as an alternative to costly ATD experiments.

<b>目标</b>：目前正开发一款适配第50百分位男性士兵的新型拟人测试装置（anthropomorphic test device, ATD），用于预测车辆乘员在遭遇下体爆炸（underbody blast, UBB）时的损伤情况。本研究的核心目标为：开发并验证一款搭载军用作战靴的ATD下肢有限元（finite element, FE）模型，将该经验证的下肢模型集成至完整的ATD模型中，并开展垂直加载仿真实验。
<b>方法</b>：基于既往实验数据，为贝尔维尔（Belleville）沙漠作战靴模型赋予接触属性与材料参数，并将该靴型模型适配至已开发的裸足ATD下肢模型。通过在垂直加速载荷传递系统（Vertically Accelerated Loads Transfer System, VALTS）上开展的6组配对组件实验完成模型验证，同时评估有限元模型的载荷传递能力与作战靴的力缓冲性能。随后将搭载作战靴的下肢子组件集成至ATD全身模型中，并开展2组全身VALTS仿真实验，以评估下肢在全身场景下的性能表现。
<b>结果</b>：在配对组件实验中，该下肢模型可精准预测足跟、胫骨及膝关节测力传感器测得的轴向载荷。将搭载作战靴的仿真载荷与裸足仿真载荷进行对比，观察到二者的缓冲效果与实验结果高度一致。在全身加载场景下，模型的运动学特性与实验记录结果匹配度良好；实验的力-时间曲线的波形与幅值均被模型精准复现。所有实验的高客观评分均验证了实验与仿真之间的良好相关性。
<b>结论</b>：在模拟下体爆炸载荷的实验中，搭载作战靴的下肢模型可如物理假人般精准实现关节运动与载荷传递，性能优异。基于该模型的表现，建议将其作为高成本ATD实验的替代方案，合理应用于相关研究中。