Chevalier Marie-Christine, Brizard Denis, Beillas Philippe
a Univ Lyon, Université Claude Bernard Lyon 1, IFSTTAR, LBMC UMR_T9406, F69622 , Lyon , France.
Traffic Inj Prev. 2019;20(1):107-113. doi: 10.1080/15389588.2018.1536823. Epub 2019 Feb 8.
The aim of this article is to report on the possible relationships between tramway front-end geometry and pedestrian injury risk over a wide range of possible tramway shapes.
To study the effect of tramway front-end shape on pedestrian injury metrics, accidents were simulated using a custom parameterized model of tramway front-end and pedestrian models available with the MADYMO multibody solver. The approach was automated, allowing the systematic exploration of tramway shapes in conjunction with 4 pedestrian sizes (e.g., 50th percentile male or M50).
A total of 8,840 simulations were run, showing that the injury risk is more important for the head than for other body regions (thorax and lower extremities). The head of the M50 impacted the windshield of the tramway in most of the configurations. Two antagonist mechanisms affecting impact velocity of the head and corresponding head injury criterion (HIC) values were observed. The first is a trunk rotation resulting from an engagement of the lower body that can contribute to an increase in head velocity in the direction of the tram. The second is the loading of the shoulder, which can accelerate the upper trunk and head away from the windshield, resulting in lower impact velocities. Groups of design were defined based on 2 main parameters (windshield height and offset), some of which seem more beneficial than others for tramway design. The pedestrian size and tramway velocity (30 vs. 20 km/h) also affected the results.
When considering only the front-end shape, the best strategy to limit the risk of head injury due to contact with the stiff windshield seems to be to promote the mechanism involving shoulder loading. Because body regions engaged vary with the pedestrian size, none of the groups of designs performed equally well for all pedestrian sizes. The best compromise is achieved with a combination of a large windscreen offset and a high windscreen. Conversely, particularly unfavorable configurations are observed for low windshield heights, especially with a large offset. Beyond the front-end shape, considering the stiffness of the current windshields and the high injury risks predicted for 30 km/h, the stiffness of the windshield should be considered in the future for further gains in pedestrian safety.
本文旨在报告在各种可能的有轨电车形状范围内，有轨电车前端几何形状与行人受伤风险之间的可能关系。
为研究有轨电车前端形状对行人受伤指标的影响，使用MADYMO多体求解器提供的有轨电车前端自定义参数化模型和行人模型对事故进行模拟。该方法是自动化的，允许结合4种行人尺寸（例如，第50百分位男性或M50）对有轨电车形状进行系统探索。
总共进行了8840次模拟，结果表明头部受伤风险比其他身体部位（胸部和下肢）更严重。在大多数配置中，M50的头部撞击有轨电车的挡风玻璃。观察到两种影响头部撞击速度和相应头部损伤标准（HIC）值的相反机制。第一种是下半身接触导致的躯干旋转，这可能有助于头部朝着有轨电车方向的速度增加。第二种是肩部受力，这可以加速上躯干和头部远离挡风玻璃，从而降低撞击速度。基于两个主要参数（挡风玻璃高度和偏移量）定义了设计组，其中一些对于有轨电车设计似乎比其他更有益。行人尺寸和有轨电车速度（30与20 km/h）也影响了结果。
仅考虑前端形状时，限制因与坚硬挡风玻璃接触而导致头部受伤风险的最佳策略似乎是促进涉及肩部受力的机制。由于参与的身体部位因行人尺寸而异，没有一组设计对所有行人尺寸都表现得同样好。通过大挡风玻璃偏移量和高挡风玻璃的组合可实现最佳折衷。相反，对于低挡风玻璃高度，特别是偏移量大时，会观察到特别不利的配置。除了前端形状外，考虑到当前挡风玻璃的刚度以及预测的30 km/h的高受伤风险，未来应考虑挡风玻璃的刚度以进一步提高行人安全性。
