利用物质点法研究不同头部模型对头部碰撞动态响应的影响

目的 探讨头部肌肉及边界条件对头部碰撞动态响应的影响。方法 通过人体扫描CT图片构建3种人体头部三维物质点碰撞模型，第1种为简化的自由头部模型（SHFr），包括头骨、膜层、脑组织，头部自由；第2种为带肌肉的自由头部模型(MHFr)，包括头部肌肉、头骨、膜层、脑组织，头部自由；第3种为带肌肉的肩部固定的模型(MHSFi)，包括头部肌肉、头骨、膜层、脑组织、肩部肌肉、肩颈部骨骼，肩部下缘固定。一铅质圆柱体锤以6.4 m/s初始速度垂直撞击前额部位，通过物质点法模拟计算3种模型的动态响应。结果 在本数值模拟条件下，SHFr、MHFr、MHSFi 3种模型的头部加速度峰值分别为6.018×103、4.69×103、4.76×103 m/s2。结论 头部肌肉的存在会分散头部的受力分布，扩大头部受力面积，减小受伤程度；在短时间冲击过程中，头部自由与肩部固定对头部动态响应的影响不大。

Effects from different head models on dynamic response of the head impact using material point method

Objective To investigate the effects of muscles and boundary conditions on head impact response. Methods Three different 3D material point impact models of human head were constructed from the CT scanned images. The first model was the simple head model (SHFr) including skull, membrane and brain, in which the head was free. The second model was the simple head model with muscle (MHFr) including skull, membrane, brain and muscle of the head, in which the head was free. The third model was the MHFr model with shoulder, in which the bottom edge of the shoulder was fixed (MHSFi). The three models were under the impact of a cylindrical lead hammer projected at a speed of 6.4 m/s to simulate the dynamic response of the three models using 3D explicit material point method code. Results The peak values of acceleration of the head centroid for the SHFr, MHFr and MHSFi model were 6.018×103, 4.69×103 and 4.76×103 m/s2, respectively. Conclusions The muscle of the head can disperse distributions of the contact force, enlarge the damage area and relieve the damage of the head. In case of short-time impact, whether the boundary of the head is free or the shoulder is fixed does not affect the dynamic response of the head impact.