Driver injury analysis and protection strategies in Moose-vehicle Collisions

• Reconstruction and Response Analysis of Moose-Vehicle Collision • Combining impact experiments and finite element analysis (FEA), this study reconstructed moose-vehicle collision (MVC) accidents and analyzed the collision process to develop a dataset of collision response parameters. An moose FE model was developed and the validity of the muscle tissue, bone, and skin models was verified through drop hammer impact tests. By coupling with a Toyota Yaris vehicle model, a moose-vehicle collision FE model was constructed and varified. Key collision boundary conditions significantly affecting vehicle response were parameterized, and full-factorial experimental designs were conducted for different collision velocities, angles, and offsets. A-pillar bending angle, cabin intrusion, and B-pillar acceleration were used to quantify the impact of all parameter. The study revealed that the moose-vehicle collision process can be divided into three phases: lower limb impact phase, rolling phase, and flight phase. Peak collision acceleration occurred in the first and last phases, while peak A-pillar bending angle and cabin intrusion occurred during the rollover phase. Collision speed and position significantly influenced vehicle response, whereas collision angle, despite affecting the sequence of moose impact locations, had statistically insignificant effects on final deformation. • Driver Injury Analysis in Moose-Vehicle Collision • Using the Prescribed Structural Motion method of MADYMO software, a driver-restraint system model was developed to replicate driver response in MVCs. With vehicle velocities, collision position, driver size, and posture as design variables, full-factorial simulations were conducted to analyze driver response. The study identified three phases of driver kinematic response: slide, impact, and rebound. The current restraint system effectively prevented driver-vehicle interior collisions during the slide phase, but head contact with the deformed windshield or roof during the contact-collision phase caused head, neck, and chest injuries, with severe injury risks in certain scenarios. Neck injuries were the most prevalent, with two potential injury modes (compression-flexion or compression-extension) depending on force and moment exerted on the head-neck complex, leading to "reclining" or "submarining" trends during rebound pahse. The most severe injuries occurred at 100 km/h, 50% offset collision, with a right posture, which was drove by A-pillar deformation and cabin intrusion. • Design and Optimization of a Top Airbag for Driver Protection in Moose-Vehicle Collisions • Based on current passive safety testing protocols, this study designed a top airbag targeting driver protection in MVCs. Applicability analyses for 5th female, 50th male, and 95th male drivers demonstrated that the airbag reduced injury metrics across all groups, though the 5th female still exhibited elevated HIC and N ij values, indicating room for optimization. With ignition timing, vent size, tether length, and gas mass flow rate as design variables and injury criteria as optimization targets, a response surface methodology established regression relationships between objectives and variables. The NSGA-II genetic algorithm was employed for multi-objective optimization, with the Pareto-optimal solution selected via the combined injury metric P joint . Validation against simulation results confirmed the optimized design’s effectiveness. In recent years, the frequency of moose-vehicle collisions (MVC) has constantly increased, becoming a serious traffic safety issue. Addressing the lack of research on collision response and driver injury in such scenarios, this study presents the following contributions: (1) A finite element (FE) model of MVC was developed and validated, analyzing the influence of impact velocity, offset, and impact angle on vehicle collision kinematics. The results show that collision speed and position are significant factors influencing the vehicle's response. (2) A driver-restraint system model was established and validated, examining the effects of impact velocity, offset, driver size, and posture on driver kinematics, dynamics and injuries. The findings indicate that the primary cause of driver injury is the head's collision with the deformed vehicle structure. The neck is the most vulnerable body part, with compression-bending or compression-extension injury modes observed. (3) Based on driver injury mechanisms, a top airbag model was proposed and designed. Using a multi-objective optimization algorithm, the airbag parameters (ignition time, gas flow rate, tether length, and vent size) were optimized for the highest risk scenario. The optimized top airbag successfully limited injury indexes across different driver sizes, improving protection and enhancing the safety of the vehicle restraint system. This study provides a comprehensive framework for driver injury and protection strategy research in MVC, contributing to improved vehicle passive safety.