Engineering a mechanical surrogate neck-form for impact testing

目前，头盔测试方法使用线性下落组件，将K1A型镁合金头模引导到冲击锤上。镁头被限制为只经历线加速度，因为它通过刚性金属颈连接到线性导轨上。虽然最初的设计不是这样做的，但这种碰撞模拟方法不会重新创建与人体的头盔碰撞的力学，在这种碰撞中，头部受到能够沿六个自由度位移/旋转的颈部的支撑和运动学影响(并允许头部旋转和体验角运动学)。一些新提出的头盔角运动学认证测试方法建议，生物逼真头颈模型应该取代镁头和刚性颈部方法。目前可用的生物逼真头部模型包括NOCSAE和HybriIII头型，这两种头型都试图重建人头的人体测量和惯性特性。目前可用的颈部模型，其中最常见的用于头盔测试的是Hybridge III颈部，被认为不能在头盔撞击中给出真实的响应，因此认证组织正在讨论可以并且应该使用什么颈部模型来进行头盔认证。Hybridge III和其他颈部模型被认为在轴向旋转和轴向压缩时机械上过于僵硬。考虑到Hybridge III Neck的最初目的是逼真地模拟正面汽车碰撞中的前后部旋转反应，这可能并不令人惊讶。与生物动力学和伙伴有限公司(渥太华)合作的目标是迈出制作适合头盔认证使用的生物逼真颈部模型的第一步。

Currently, helmet test methods use linear drop assemblies that guide a K1A magnesium headform onto an impact anvil. The magnesium head is constrained to experience only linear acceleration because it is attached to the linear guide via a rigid metal neck. While it was not originally designed to do so, this impact simulation method does not recreate the mechanics of helmeted impact with a human, where the head is supported and kinematically influenced by a neck capable of displacing/rotating along six degrees of freedom (and which allows the head to rotate and experience angular kinematics). Some of the new proposed test methods for helmet certification with angular kinematics have suggested that biofidelic head-neck models should replace the magnesium head and rigid neck methods. Biofidelic head models that are currently available include the NOCSAE and HybridIII headforms, both of which attempt to recreate anthropometry and inertial properties of the human head. Currently available neck models, the most common of which used in helmet testing is the HybridIII neck, are not considered to give realistic response in helmeted impact, and as a result the certification organizations are discussing what, if any, neck model could and should be used for helmet certification. The HybridIII, and other neck models, are accepted to be much too mechanically stiff in axial rotation and axial compression. This is perhaps not surprising given the original purpose of the HybridIII neck, which was to realistically simulate fore-aft rotational response in frontal automotive impacts. The objective of this partnership with Biokinetics and Associates Ltd. (Ottawa ON) is to take the first steps towards prototyping a biofidelic neck model suitable for use in helmet certification.