University of Virginia Center for Applied Biomechanics.
Autoliv Development AB.
Stapp Car Crash J. 2020 Nov;64:83-153. doi: 10.4271/2020-22-0004.
Frontal impacts with reclined occupants are rare but severe, and they are anticipated to become more common with the introduction of vehicles with automated driving capabilities. Computational and physical human surrogates are needed to design and evaluate injury countermeasures for reclined occupants, but the validity of such surrogates in a reclined posture is unknown. Experiments with post-mortem human subjects (PMHS) in a recline posture are needed both to define biofidelity targets for other surrogates and to describe the biomechanical response of reclined occupants in restrained frontal impacts. The goal of this study was to evaluate the kinematic and injury response of reclined PMHS in 30 g, 50 km/h frontal sled tests. Five midsize adult male PMHS were tested. A simplified semi-rigid seat with an anti-submarining pan and a non-production threepoint seatbelt (pre-tensioned, force-limited, seat-integrated) were used. Global motions and local accelerations of the head, pelvis, and multiple vertebrae were measured. Seat and seatbelt forces were also measured. Injuries were assessed via post-test dissection. The initial reclined posture aligned body regions (pelvis, lumbar spine, and ribcage) in a way that reduced the likelihood of effective restraint by the seat and seatbelt: the occupant's pelvis was initially rotated posteriorly, priming the occupant for submarining, and the lumbar spine was loaded in combined compression and bending due to the inertia of the upper torso during forward excursion. Coupled with the high restraining forces of the seat and seatbelt, the unfavorable kinematics resulted in injuries of the sacrum/coccyx (four of five PMHS injured), iliac wing (two of five PMHS injured), lumbar spine (three of five PMHS injured), and ribcage (all five PMHS suffered sternal fractures, and three of five PMHS suffered seven or more rib fractures). The kinematic and injury outcomes strongly motivate the development of injury criteria for the lumbar spine and pelvis, the inclusion of intrinsic variability (e.g., abdomen depth and pelvis shape) in computational simulations of frontal impacts with reclined occupants, and the adaptation of comprehensive restraint paradigms to predicted variability of occupant posture.
正面碰撞中，后排乘客躺卧的情况很少见，但却非常严重，随着自动驾驶车辆的引入，这种情况预计会更加常见。为了设计和评估后排躺卧乘客的防护措施，需要使用计算和物理人体替身，但这些替身在后卧姿势下的有效性尚不清楚。因此，需要对躺卧姿势下的尸体进行实验，以确定其他替身的生物逼真度目标，并描述约束性正面碰撞中后排躺卧乘客的生物力学反应。本研究的目的是评估 30g、50km/h 正面滑橇试验中躺卧尸体模型的运动学和损伤反应。共测试了 5 名中等身材的成年男性尸体模型。使用简化的半刚性座椅和防潜座椅以及非生产的三点式安全带（预张紧、力限制、座椅集成）。测量了头部、骨盆和多个脊椎的整体运动和局部加速度。还测量了座椅和安全带的力。通过测试后的解剖评估损伤。初始躺卧姿势使身体区域（骨盆、腰椎和肋骨）对齐，从而降低了座椅和安全带有效约束的可能性：乘客的骨盆最初向后旋转，为乘客的潜泳做好准备，并且由于上半身在向前移动过程中的惯性，腰椎同时承受压缩和弯曲的负荷。再加上座椅和安全带的高约束力，这种不利的运动学导致了骶骨/尾骨（五具尸体模型中有四具受伤）、髂骨翼（五具尸体模型中有两具受伤）、腰椎（五具尸体模型中有三具受伤）和肋骨（所有五具尸体模型都遭受胸骨骨折，其中三具尸体模型遭受了 7 根或更多肋骨骨折）。运动学和损伤结果强烈促使开发用于腰椎和骨盆的损伤标准，将固有变异性（例如腹部深度和骨盆形状）纳入带有躺卧乘客的正面碰撞的计算模拟中，并根据乘客姿势的可预测变异性调整综合约束方案。
