Bonin Stephanie J, Gardiner John C, Onar-Thomas Arzu, Asfour Shihab S, Siegmund Gunter P
University of Miami, Department of Industrial Engineering, 1251 Memorial Dr, Coral Gables, FL 33146, USA; MEA Forensic Engineers & Scientists, 23281 Vista Grande Dr, Laguna Hills, CA 92603, USA.
MEA Forensic Engineers & Scientists, 23281 Vista Grande Dr, Laguna Hills, CA 92603, USA.
Accid Anal Prev. 2017 Sep;106:315-326. doi: 10.1016/j.aap.2017.06.015. Epub 2017 Jul 10.
Proper helmet fit is important for optimizing head protection during an impact, yet many motorcyclists wear helmets that do not properly fit their heads. The goals of this study are i) to quantify how a mismatch in headform size and motorcycle helmet size affects headform peak acceleration and head injury criteria (HIC), and ii) to determine if peak acceleration, HIC, and impact speed can be estimated from the foam liner's maximum residual crush depth or residual crush volume. Shorty-style helmets (4 sizes of a single model) were tested on instrumented headforms (4 sizes) during linear impacts between 2.0 and 10.5m/s to the forehead region. Helmets were CT scanned to quantify residual crush depth and volume. Separate linear regression models were used to quantify how the response variables (peak acceleration (g), HIC, and impact speed (m/s)) were related to the predictor variables (maximum crush depth (mm), crush volume (cm), and the difference in circumference between the helmet and headform (cm)). Overall, we found that increasingly oversized helmets reduced peak headform acceleration and HIC for a given impact speed for maximum residual crush depths less than 7.9mm and residual crush volume less than 40cm. Below these levels of residual crush, we found that peak headform acceleration, HIC, and impact speed can be estimated from a helmet's residual crush. Above these crush thresholds, large variations in headform kinematics are present, possibly related to densification of the foam liner during the impact.
合适的头盔佩戴对于在撞击过程中优化头部保护至关重要，但许多摩托车骑行者佩戴的头盔尺寸并不适合他们的头部。本研究的目标是：i）量化头型尺寸与摩托车头盔尺寸不匹配如何影响头型峰值加速度和头部损伤标准（HIC）；ii）确定是否可以从泡沫衬垫的最大残余挤压深度或残余挤压体积来估计峰值加速度、HIC和撞击速度。在对前额区域进行2.0至10.5m/s的线性撞击期间，在仪器化头型（4种尺寸）上测试了短款头盔（单一型号的4种尺寸）。对头盔进行CT扫描以量化残余挤压深度和体积。使用单独的线性回归模型来量化响应变量（峰值加速度（g）、HIC和撞击速度（m/s））与预测变量（最大挤压深度（mm）、挤压体积（cm）以及头盔与头型之间的周长差（cm））之间的关系。总体而言，我们发现对于最大残余挤压深度小于7.9mm且残余挤压体积小于40cm的情况，对于给定的撞击速度，头盔尺寸越大，头型峰值加速度和HIC越低。在这些残余挤压水平以下，我们发现可以从头盔的残余挤压来估计头型峰值加速度、HIC和撞击速度。在这些挤压阈值以上，头型运动学存在很大差异，这可能与撞击过程中泡沫衬垫的致密化有关。
