用于儿童头部损伤生物力学研究的碰撞理论模型建立及验证

机动车事故和跌落等碰撞工况是造成儿童头部受伤的重要原因，研究碰撞过程中儿童头部的动力学响应对于头部损伤的预测具有重要意义。头部动力学模型能够快速预测不同碰撞场景下头部动态响应结果并进而预测头部损伤风险。首先，建立考虑颅骨及皮肤厚度和形态曲率的儿童头部碰撞理论模型用于预测儿童头部在碰撞工况下的响应。然后，通过儿童头部CT扫描提取颅骨及皮肤几何结构，对颅骨和皮肤三维重建后进行分割和定量离散，分别得到能描述颅骨内侧、颅骨外侧及皮肤形态的离散点集群，通过计算得到碰撞点周围的平均曲率与厚度，基于建立的头部碰撞理论模型可计算不同碰撞位置(不同厚度和曲率)的碰撞力。最后，通过碰撞试验对建立的碰撞理论模型进行验证，使用不同年龄的小型猪头部作为儿童头部的代替品进行碰撞试验，将试验结果与上述建立的理论模型对小型猪头部碰撞响应的预测结果(基于小型猪头部的真实的形态曲率、皮肤和颅骨厚度数据)进行对比。研究结果表明：建立的理论模型可以较为准确地预测碰撞脉宽和最大碰撞力；提出的儿童头部碰撞动力学理论模型能够快速预测头部不同碰撞位置的动力学响应，可以为儿童头部损伤的进一步研究提供参考和理论支撑。

Development and Validation of Impact Theoretical Model for Study of Pediatric Head Injury Biomechanics

Motor vehicle accidents and falls are two primary causes of pediatric head injuries. Studying the dynamic response of the child's head is important to predict head injury when subjected to impact. The head dynamic model can rapidly predict the global dynamic response of the head under different impact scenarios and further predict the head injury risk. In this study, a theoretical dynamic model was developed to predict the child head impact response by considering the thickness and curvature of the skull and skin. Second, the structures of the skull and skin were extracted from CT scans. Quantitative discrete point sets were obtained to represent the skull and skin structures through image reconstruction, segmentation, and dispersion. The average radius and thickness of the head at a given impact position were calculated, and then the maximum head force at different impact positions was calculated based on the aforementioned theoretical model. Finally, the developed theoretical model was validated against experimental results. Specifically, impact tests were conducted on piglets of different ages as substitutes for children. The experimental results were compared with those predicted by the theoretical model, in which the predicted results were calculated according to the specified head curvature and thickness of the skin and skull. The results show that the developed theoretical head model can predict the duration and maximum impact force accurately. In summary, the developed theoretical model can rapidly predict head global responses at different impact positions, which can provide references and a theoretical basis for the further study of pediatric head injuries.