Norman R W, Bishop P J, Pierrynowski M R, Pezzack J C
Aviat Space Environ Med. 1979 Jun;50(6):553-61.
The response of the Gentex DH-151 (contact type) and Gentex 411 (suspension type) aircrew helmets to low-magnitude impacts, such as those sometimes encountered during cockpit buffeting, in ejection, and in parachute landings, was studied to augment the data base on helmet performance. The helmets, mounted on a Hodgson headform, were dropped on the crown and rear at impact velocities up to 4.97 m/s. Acceleration time histories were tape recorded and digitized and Gadd Severity Indices (GSI), among others, were calculated from the resultant acceleration curve. Both helmets kept the GSI below predicted concussion thresholds at 4.97 m/s and were considered to perform well on initial impacts. On second impacts, the GSI rose considerably because the shell and liner of the DH-151 cracked and the suspension of the "141" stretched during the first blow. Improvement of the multiple impact performance of both helmets appears desirable, although the suspension helmet performed slightly better than the contact helmet with respect to the criterion used.
为扩充头盔性能的数据库，对Gentex DH - 151（接触式）和Gentex 411（悬挂式）航空人员头盔在低强度冲击下的响应进行了研究，这些冲击有时会在驾驶舱抖振、弹射和降落伞着陆过程中遇到。将头盔安装在霍奇森头模上，以高达4.97 m/s的冲击速度从头顶和后部掉落。加速度时间历程被磁带记录并数字化，从中计算出包括加德严重度指数（GSI）等参数。在4.97 m/s的冲击速度下，两种头盔的GSI均保持在预测的脑震荡阈值以下，被认为在初次冲击时表现良好。在二次冲击时，GSI大幅上升，因为DH - 151的外壳和衬里出现裂缝，“141”的悬挂装置在第一次撞击时拉伸。尽管就所使用的标准而言，悬挂式头盔的表现略优于接触式头盔，但改善两种头盔的多次冲击性能似乎是可取的。
