Department of MME, University of Waterloo, 200 University Avenue West, Waterloo, ON N2 L 3G1, Canada.
Army Futures Command, CCDC Army Research Laboratory, Aberdeen Proving Ground, MD 21005.
J Biomech Eng. 2021 Mar 1;143(3). doi: 10.1115/1.4048644.
Nonperforating ballistic impacts on thoracic armor can cause blunt injuries, known as behind-armor blunt trauma (BABT). To evaluate the potential for this injury, the back face deformation (BFD) imprinted into a clay backing is measured; however, the link between BFD and potential for injury is uncertain. Computational human body models (HBMs) have the potential to provide an improved understanding of BABT injury risk to inform armor design but require assessment with relevant loading scenarios. In this study, a methodology was developed to apply BABT loading to a computational thorax model, enhanced with refined finite element mesh and high-deformation rate mechanical properties. The model was assessed using an epidemiological BABT survivor database. BABT impact boundary conditions for 10 cases from the database were recreated using experimentally measured deformation for specific armor/projectile combinations, and applied to the thorax model using a novel prescribed displacement methodology. The computational thorax model demonstrated numerical stability under BABT impact conditions. The predicted number of rib fractures, the magnitude of pulmonary contusion, and injury rank, increased with armor BFD, back face velocity, and input energy to the thorax. In three of the 10 cases, the model overpredicted the number of rib fractures, attributed to impact location positional sensitivity and limited details from the database. The integration of an HBM with the BABT loading method predicted rib fractures and injury ranks that were in good agreement with available medical records, providing a potential tool for future armor evaluation and injury assessment.
非贯穿性弹道冲击胸部装甲可导致钝性伤，称为装甲背面钝性创伤（BABT）。为了评估这种损伤的可能性，测量了印在粘土背衬上的背面变形（BFD）；然而，BFD 与潜在损伤之间的联系尚不确定。计算人体模型（HBM）有可能提供对 BABT 损伤风险的更好理解，从而为装甲设计提供信息，但需要使用相关加载情况进行评估。在这项研究中，开发了一种将 BABT 加载应用于计算胸部模型的方法，该模型采用了改进的有限元网格和高应变速率力学特性进行了增强。该模型使用流行病学 BABT 幸存者数据库进行了评估。使用针对特定装甲/弹丸组合的实验测量变形，为数据库中的 10 个案例重现了 BABT 冲击的边界条件，并使用新的规定位移方法将其应用于胸部模型。计算胸部模型在 BABT 冲击条件下表现出数值稳定性。肋骨骨折的数量、肺挫伤的程度以及损伤等级随着装甲 BFD、背面速度和输入到胸部的能量的增加而增加。在 10 个案例中的 3 个中，模型过高预测了肋骨骨折的数量，这归因于冲击位置的位置敏感性和数据库中的有限细节。HBM 与 BABT 加载方法的集成预测了肋骨骨折和损伤等级，与现有医疗记录非常吻合，为未来的装甲评估和损伤评估提供了一种潜在工具。
