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 50^th percentile male soldier is being developed to predict injuries to a vehicle occupant during an under-body 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. Secondly, 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 six 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 sub-assembly 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 a similar amount of mitigation as 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 was 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 under-body loading experiments. The performance of the model leads to the recommendation to use it appropriately as an alternative to costly ATD experiments.