Individuals exposed to the propagation of shock waves generated by the detonation of explosive charges may suffer Traumatic Brain Injury. The mechanism of cranial deflection is one of many hypotheses that could explain the observed brain damage. To investigate this physical phenomenon in a reproducible manner, a new simplified cranial substitute was designed with a mechanical response close to that of a human skull when subjected to this type of loading. As a first step, a Finite Element Model was employed to dimension the new substitute. The objective was indeed to obtain a vibratory behavior close to that of a dry human skull over a wide range of frequencies up to 10 kHz. As a second step, the Finite Element Model was used together with Experimental Modal Analyses to identify the vibration modes of the substitute. A shaker excited the structure via a metal rod, while a laser vibrometer recorded the induced vibrations at defined measurement points. The results showed that despite differences in material properties and geometry, the newly developed substitute has 10/13 natural frequencies in common with those of dry human skulls. When filled with a simulant of cerebral matter, it could therefore be used in future studies as an approximation to assess the mechanical response of a simplified skull substitute to a blast threat.

中文翻译：

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设计一种模态行为接近人类头骨的简化颅骨替代品

暴露于炸药爆炸产生的冲击波传播的个人可能会遭受创伤性脑损伤。颅骨偏转机制是可以解释所观察到的脑损伤的众多假设之一。为了以可重复的方式研究这种物理现象，设计了一种新的简化颅骨替代品，其在承受此类负载时的机械响应接近人类头骨的机械响应。第一步，采用有限元模型来确定新替代品的尺寸。其目标确实是在高达 10 kHz 的广泛频率范围内获得接近干燥人类头骨的振动行为。第二步，将有限元模型与实验模态分析一起使用来识别替代品的振动模式。振动台通过金属棒激发结构，而激光振动计则记录定义测量点处的诱发振动。结果表明，尽管材料特性和几何形状存在差异，但新开发的替代品具有与干燥人类头骨相同的 10/13 固有频率。因此，当填充大脑物质的模拟物时，它可以在未来的研究中用作近似值，以评估简化的头骨替代品对爆炸威胁的机械反应。