Engineering a mechanical surrogate neck-form for impact testing

目前，头盔测试方法使用将K1 A镁人头模型引导到冲击砧上的线性跌落组件。由于镁股骨头通过刚性金属颈部连接到线性导轨上，因此镁股骨头只能承受线性加速度。虽然最初并没有设计成这样做，但是这种冲击模拟方法并没有再现戴头盔的人的冲击的力学，其中头部由能够沿着沿着六个自由度移位/旋转的颈部支撑并且在运动学上受到颈部的影响（并且这允许头部旋转并且经历角运动学）。一些新提出的头盔角运动学认证测试方法建议，生物力学头颈模型应取代镁头和刚性颈部方法。目前可用的仿生头部模型包括NOCSAE和HybridIII头模，两者都试图重现人体测量和人类头部的惯性特性。目前可用的颈部模型，其中最常见的用于头盔测试的是HybridIII颈部，被认为不能在头盔冲击中给出真实的响应，因此认证组织正在讨论什么样的颈部模型（如果有的话）可以并且应该用于头盔认证。HybridIII和其他股骨颈型号在轴向旋转和轴向压缩方面的机械刚度太大。考虑到HybridIII颈部的最初目的，这可能并不奇怪，这是为了真实地模拟汽车正面碰撞中的前后旋转响应。此次与Biokidol and Associates Ltd.（渥太华ON）合作的目的是迈出第一步，为适用于头盔认证的生物颈部模型制作原型。

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.