Shirzadi Hooman, Zohoor Hassan, Naserkhaki Sadegh
1 Department of Mechanical Engineering, Sharif University of Technology, Tehran, Iran.
2 Center of Excellence in Design, Robotics and Automation, Sharif University of Technology, Academician, Academy of Sciences of IR Iran.
Proc Inst Mech Eng H. 2018 Jul;232(7):699-707. doi: 10.1177/0954411918778063. Epub 2018 Jun 10.
Airbags are safety devices in vehicles effectively suppressing passengers' injuries during accidents. Although there are still many cases of eye injuries reported due to eye-airbag impacts in recent years. Biomechanical approaches are now feasible and can considerably help experts to investigate the issue without ethical concerns. The eye-airbag impact-induced stresses/strains in various components of the eye were found to investigate the risk of injury in different conditions (impact velocity and airbag pressure). Three-dimensional geometry of the eyeball, fat and bony socket as well as the airbag were developed and meshed to develop a finite element model. Nonlinear material properties of the vitreous body and sclera were found through the in vitro tests on ovine samples and for the other components were taken from the literature. The eye collided the airbag due to the velocity field in the dynamic explicit step in Abaqus. Results of compression tests showed a nonlinear curve for vitreous body with average ultimate stress of 22 (18-25) kPa. Tensile behavior of sclera was viscoelastic nonlinear with ultimate stresses changing from 2.51 (2.3-2.7) to 4.3 (4-4.6) MPa when loading strain rate increased from 10 to 600 mm/min. Sclera, ciliary body, cornea and lens were the eye components with highest stresses (maximum stress reached up to 9.3 MPa). Cornea, retina and choroid experienced the highest strains with the maximum up to 14.1%. According to the previously reported injury criteria for cornea, it was at high risk of injury considering both stress and strains. Reduced pressure of the airbag was beneficial decreased stress of all components. Comprehensive investigations in this area can disclose biomechanical behavior of the eye during eye-airbag impact. Effective guidelines can be drawn for airbag design for instance the airbag pressure which reduces risk of eye injury.
安全气囊是车辆中的安全装置，可在事故期间有效抑制乘客受伤。尽管近年来仍有许多因眼睛与安全气囊碰撞而导致眼外伤的案例报道。生物力学方法现在是可行的，并且可以极大地帮助专家在没有伦理问题的情况下研究这个问题。通过研究眼睛各组成部分中因眼睛与安全气囊碰撞而产生的应力/应变，来探究不同条件（撞击速度和安全气囊压力）下的受伤风险。构建了眼球、脂肪和骨眼眶以及安全气囊的三维几何模型并进行网格划分，以建立有限元模型。玻璃体和巩膜的非线性材料特性通过对羊样本的体外测试获得，其他组成部分的材料特性则取自文献。在Abaqus的动态显式步骤中，由于速度场的作用，眼睛与安全气囊发生碰撞。压缩试验结果显示玻璃体的应力曲线呈非线性，平均极限应力为22（18 - 25）kPa。巩膜的拉伸行为是粘弹性非线性的，当加载应变率从10 mm/min增加到600 mm/min时，极限应力从2.51（2.3 - 2.7）MPa变化到4.3（4 - 4.6）MPa。巩膜、睫状体、角膜和晶状体是应力最高的眼部组成部分（最大应力达到9.3 MPa）。角膜、视网膜和脉络膜经历的应变最高，最大可达14.1%。根据先前报道的角膜损伤标准，从应力和应变两方面考虑，角膜处于高损伤风险。降低安全气囊压力有利于降低所有组成部分的应力。该领域的综合研究可以揭示眼睛与安全气囊碰撞过程中的生物力学行为。例如，可以为安全气囊设计制定有效的指导方针，如降低眼睛受伤风险的安全气囊压力。
