功能梯度仿生头盔防护性能与头部损伤分析

Analysis on Head Injury and Protective Performance of Functionally Graded Bionic Helmet

为了提高摩托车头盔防护性能降低头部损伤风险,本文引入功能梯度仿生泡沫结构替代传统头盔的均匀密度泡沫衬垫.通过头盔耦合生物力学头部有限元模型,获取撞击过程中头部质心加速度、生物力学响应和头盔结构响应,综合分析不同密度梯度方案对头盔防护能力的影响.结果表明,功能梯度泡沫结构在中高速冲击下有更明显的优势.相比传统头盔吸能缓冲层的均匀泡沫密度方案和新型头盔的正/负密度梯度方案,最大密度为80 kg/m3的负密度梯度泡沫设计方案可以更有效改善头盔结构碰撞响应并降低碰撞过程中头部损伤,且随着密度差的增大,负密度梯度头盔的防护性能得到了进一步提高.

Functionally graded foam is introduced in this paper to replace the uniform-density energy-absorbing liner of a conventional motorcycle helmet for improving its protection performance and further reducing head injuries during impact scenarios.The helmet finite element model coupled with biomechanical head model was developed,the acceleration transmitted to the gravity center of head,biomechanical responses of the head and crushing behaviors of the helmet under the impacts are obtained to comprehensively investigate the effects of functionally graded foam on helmet impact protection.According to the results,functionally graded foam has more advantages under medium/high speed impact than uniform liner foam.In comparison with the uniform-density design for the conventional helmet liner and the positive/negative functionally graded foam design for the novel helmet liner,the negative functionally graded foam with a maximum density of 80 kg/m3 is of the best crushing responses and the severities of head injuries can be reduced more effectively.With the increase of density difference,the impact protection of novel helmet with negative functionally graded foam design can be further improved.