Despite the use of helmets in American football, brain injuries are still prevalent. To reduce the burden of these injuries, novel impact mitigation systems are needed. The Vicis Zero1 (VZ1) American football helmet is unique in its use of multi-directional buckling structures sandwiched between a deformable outer shell and a stiff inner shell. The objective of this study was to develop a model of the VZ1 and to assess this unique characteristic for its role in mitigating head kinematics. The VZ1 model was developed using a bottom-up framework that emphasized material testing, constitutive model calibration, and component-level validation. Over 50 experimental tests were simulated to validate the VZ1 model. CORrelation and Analysis (CORA) was used to quantify the similarity between experimental and model head kinematics, neck forces, and impactor accelerations and forces. The VZ1 model demonstrated good correlation with an overall mean CORA score of 0.86. A parametric analysis on helmet compliance revealed that the outer shell and column stiffness influenced translational head kinematics more than rotational. For the material parameters investigated, head linear acceleration ranged from 80 to 220 g, whereas angular velocity ranged from 37 to 40 rad/s. This helmet model is open-source and serves as an in silico design platform for helmet innovation.

中文翻译：

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撞击下可变形美式橄榄球头盔的有限元模型。

尽管在美式橄榄球中使用了头盔，但是脑部伤害仍然很普遍。为了减轻这些伤害的负担，需要新颖的冲击减轻系统。Vicis Zero1（VZ1）美式橄榄球头盔的独特之处在于，它采用了夹在可变形外壳和坚硬内壳之间的多向屈曲结构。这项研究的目的是开发VZ1的模型并评估其在减轻头部运动学方面的作用的独特特征。VZ1模型是使用自下而上的框架开发的，该框架强调了材料测试，本构模型校准和组件级验证。模拟了50多个实验测试以验证VZ1模型。关联和分析（CORA）用于量化实验和模型头部运动学，颈部力，冲击器的加速度和力。VZ1模型显示出良好的相关性，总体平均CORA得分为0.86。对头盔顺应性的参数分析显示，外壳和立柱的刚度对平移头运动的影响大于对旋转运动的影响。对于所研究的材料参数，杆头线性加速度的范围为80至220 g，而角速度的范围为37至40 rad / s。该头盔模型是开源的，可作为头盔创新的计算机设计平台。头部线性加速度的范围为80至220 g，而角速度的范围为37至40 rad / s。该头盔模型是开源的，可作为头盔创新的计算机设计平台。头部线性加速度的范围为80至220 g，而角速度的范围为37至40 rad / s。该头盔模型是开源的，可作为头盔创新的计算机设计平台。