MEA Forensic Engineers & Scientists, 11-11151 Horseshoe Way, Richmond, BC V7A 4S5, Canada.
MEA Forensic Engineers & Scientists, 23281 Vista Grande Dr., Suite A, Laguna Hills, CA 92653, USA.
Accid Anal Prev. 2016 Jul;92:175-83. doi: 10.1016/j.aap.2016.03.027. Epub 2016 Apr 11.
Bicycle helmets reduce the frequency and severity of severe to fatal head and brain injuries in bicycle crashes. Our goal here was to measure the impact attenuation performance of common bicycle helmets over a range of impact speeds. We performed 127 drop tests using 13 different bicycle helmet models (6 traditional style helmets and 7 BMX-style helmets) at impact speeds ranging from 1 to 10m/s onto a flat anvil. Helmets were struck on their left front and/or right front areas, a common impact location that was at or just below the test line of most bicycle helmet standards. All but one of the 10 certified helmet models remained below the 300g level at an impact speed of 6m/s, whereas none of the 3 uncertified helmets met this criterion. We found that the helmets with expanded polystyrene liners performed similarly and universally well. The single certified helmet with a polyurethane liner performed below the level expected by the Consumer Product Safety Commission (CPSC) standard at our impact location and the helmet structure failed during one of two supplemental tests of this helmet above the test line. Overall, we found that increased liner thickness generally reduced peak headform acceleration, particularly at higher impact speeds.
自行车头盔可降低自行车事故中严重至致命的头部和脑部受伤的频率和严重程度。我们的目标是测量常见自行车头盔在一系列冲击速度下的冲击衰减性能。我们在冲击速度为 1 至 10m/s 的情况下，对 13 种不同的自行车头盔模型（6 种传统样式头盔和 7 种 BMX 样式头盔）进行了 127 次跌落测试，冲击位置在平砧的前左或前右区域，这是大多数自行车头盔标准测试线或其下方的常见冲击位置。在 6m/s 的冲击速度下，除了一个认证头盔模型外，所有 10 个认证头盔模型的加速度都低于 300g 水平，而 3 个未经认证的头盔模型都没有达到这个标准。我们发现，带有膨胀聚苯乙烯衬垫的头盔表现相似且普遍良好。在我们的冲击位置，唯一带有聚氨酯衬垫的认证头盔的性能低于消费者产品安全委员会 (CPSC) 标准的预期水平，并且在对该头盔进行两次高于测试线的补充测试中，头盔结构在其中一次测试中失效。总的来说，我们发现衬垫厚度的增加通常会降低峰值头部加速度，尤其是在更高的冲击速度下。
