Current highly automated vehicle concepts include reclined seat layouts that could allow occupants to relax during the drive. The main objective of this study was to investigate the effects of seat pan and pelvis angles on the kinematics and injury risk of a reclined occupant by numerical simulation of a frontal sled test. The occupant, represented by a detailed 50th percentile male human body model, was positioned on a semi-rigid seat. Three seat pan angles (5, 15, and 25 degrees from the horizontal) were used, all with a seatback angle of 40 degrees from the vertical. Three pelvis angles (60, 70, and 80 degrees from the vertical), representing a nominal and two relaxed sitting positions, were used for each seat pan angle. The model was restrained using a pre-inflated airbag and a three-point seatbelt equipped with a pretensioner and a load limiter before being subjected to two frontal crash pulses. Both model kinematic response and predicted injury risk were affected by the seat pan and the pelvis angles in a reclined seatback position. Submarining occurrence and injury risk increased with lower seat pan angle, higher pelvis angle, and acceleration pulse severity. In some cases (in particular for a 15 degrees seat pan), a small variation in seat pan or pelvis angle resulted in large differences in terms of kinematics and predicted injury. This study highlights the potential effects of the seat pan and pelvis angles for reclined occupant protection. These parameters should be assessed experimentally with volunteers to determine which combinations are most likely to be adopted for comfort and with post mortem human surrogates to confirm their significance during impact and to provide data for model validation. The sled and restraint models used in this study are provided under an open-source license to facilitate further comparisons.

中文翻译：

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正面碰撞期间座椅板和骨盆角度对斜倚位置的乘员反应的影响。

当前高度自动化的车辆概念包括倾斜座椅布局，可以让乘员在驾驶过程中放松。本研究的主要目的是通过正面雪橇试验的数值模拟来研究座椅底板和骨盆角度对斜倚乘员的运动学和伤害风险的影响。由详细的 50% 男性人体模型代表的乘员被放置在半刚性座椅上。使用了三个座椅底板角度（与水平方向成 5、15 和 25 度），所有座椅靠背角度都与垂直方向成 40 度。三个骨盆角度（与垂直线成 60、70 和 80 度），代表标称坐姿和两个放松坐姿，用于每个座板角度。在受到两次正面碰撞脉冲之前，该模型使用预充气安全气囊和配备预紧器和负载限制器的三点式安全带进行约束。模型运动学响应和预测的伤害风险都受到座椅底板和倾斜座椅靠背位置的骨盆角度的影响。下潜发生和受伤的风险随着座椅盘角、骨盆角和加速脉冲强度的降低而增加。在某些情况下（特别是对于 15 度的座板），座板或骨盆角度的微小变化会导致运动学和预测伤害方面的巨大差异。该研究强调了座椅底板和骨盆角度对斜倚乘员保护的潜在影响。这些参数应该与志愿者一起进行实验评估，以确定哪些组合最有可能被采用以获得舒适感，并与死后人类替代物一起进行评估，以确认它们在撞击过程中的重要性并为模型验证提供数据。本研究中使用的雪橇和约束模型是在开源许可下提供的，以促进进一步的比较。