基于空气流场压力分析的头盔冲击波防护效能研究

研究典型战斗头盔对爆炸冲击波致颅脑冲击伤的防护效能。首先开展了50 g TNT距有无头盔防护下头部模型1 m处爆炸的抗爆试验，采集了有无防护下头部前额、颅顶、颅后冲击波超压并进行了对比分析；建立了具有典型颅脑结构的头部有限元模型并进行爆炸冲击波加载，对试验工况进行了仿真再现，通过试验结果验证了仿真模型有效性；同时利用数值仿真对不同工况下冲击波流场压力变化规律进行分析；进一步利用数值仿真研究了泡沫衬垫对头盔防护能力的影响。研究结果表明，典型战斗头盔可使前额空气超压衰减为无防护时的54.5%，但是会使颅后空气超压增强为无防护时的2.19倍，对颅后冲击波防护产生负面效果；头盔悬挂中泡沫衬垫能消弱头盔对颅后防护的负面效果，提高头盔对冲击波的防护能力。

A study of blast wave protection efficiency of helmet based on air flow field pressure analysis

To study the protective effect of a typical combat helmet against traumatic brain injury induced by blast wave, an anti-explosion test was first carried out, in which 50 g TNT was used to produce blast wave acting on a head model with or without helmet protection located at 1m away from explosion position. Pressure sensors were installed on the forehead, cranial, parietal and postcranial of the head model, while the front end of each sensor was in touch with the surface of the head model. Secondly, based on the 3rd Military Medical University’s visualization body slice data set (CVH), a finite element model with the typical head structure was established. The head of the finite element model contained skin, skull, cranial, cerebrospinal fluid, brain tissue, dura mater and pia mater. All the membrane structures are meshed into quadrilateral shell elements, while the remaining parts are all meshed into cubic solid elements. The finite element model of the head is then loaded by the blast wave, and the experimental conditions are simulated by the display dynamic analysis software of LS-DYNA. The validity of the simulation model is verified by the test results. Next, the pressure variation of the blast wave flow field under different working conditions is analyzed by numerical simulation, meanwhile the effect of foam liner on helmet protection capability is studied. The results show that the typical combat helmet can attenuate the frontal air overpressure to 54.5% of that without helmet protection, but it would enhance the air overpressure on the posterior cranial to 2.19 times that without protection, which harms the protection of posterior cranial. The foam padding in helmet suspension can reduce the negative effect of the helmet on cranial posterior protection and improve the protective ability of the helmet against the blast wave. The results also show that the auricle structure amplifies the overpressure of the blast wave to 1.7 times the free field in the same position under the frontal blast wave, which is an important target organ of blast wave action.