Guibing Li

A Study of Fatality Risk and Head Dynamic Response of Cyclist and Pedestrian Based on Passenger Car Accident Data Analysis and Simulations

Objective: The current study aims to compare the fatality risk of pedestrians and cyclists in urban traffic through an analysis of real-world accident data in China. Methods: First, 438 cases, including 371 pedestrian cases and 67 cyclist cases, were selected as a sample from the accidents collected through an in-depth investigation of vehicle accidents in China. A statistical measurement of the fatality risk with respect to impact velocity was carried out using a logistic regression analysis. Furthermore, 21 pedestrian and 24 cyclist accidents were selected for reconstruction with the MADYMO program. A comparative analysis was conducted based on the results from accident analysis and simulations for the fatality risk and head dynamic response of pedestrians and cyclists. Results: The results indicate that the vehicle impact velocity has a significant relationship with the fatality risk of both pedestrians and cyclists. The fatality risks at 50 km/h are more than twice as high as the risk at 40 km/h and about 5 times as high as that at 30 km/h for both pedestrians and cyclists. Moreover, cyclists suffered slightly lower fatality risk compared to pedestrians. The corresponding vehicle impact velocity is 65.4 km/h for pedestrian with a fatality risk of 50 percent, whereas for cyclists it is 67.6 km/h. In addition, the head impact conditions between pedestrians and cyclists are different. Conclusions: These findings offer potential contributions for establishing a more reasonable speed limit for urban traffic in China and generating strategies for cyclists’ and pedestrians’ head protection.

Finite Element Analysis of Thorax Responses Under Quasi-Static and Dynamic Loading

This study aimed at investigation of the response of the human thorax under various loading conditions. For this purpose an FE thorax model was developed based on the human anatomical structures. The human thorax consists of ribs, thoracic vertebrae and intervertebral discs, a sternum, costal cartilages and internal organs. Material properties used in this study were based on the published literature. The FE model was used to simulate the phenomenon of thorax compression. The simulations were carried out in different configurations, including the three-point bending of single rib and frontal impacting with a cylinder to a complete thorax at low speed. The results from simulations were compared with the impact responses obtained from biological tests, such as 3-point bending tests and rib structural tests. The entire thorax model was then tested by simulation of volunteer test. The responses predicted by the simulation showed a good biofidelity.

Influence of Vehicle Front Structure on Compatibility of Passenger Car-to-SUV Frontal Crash

Front structure of vehicle is one of the major factors which influence compatibility in vehicle-to-vehicle frontal crash. However, the influence of vehicle front structure with different overlap ratios has not well studied yet. Based on the simulation results of a small car to an SUV frontal crash, the compatibility was investigated in terms of the vehicle frontal stiffness and geometry height with different overlap ratios. The amount of the intrusion of the small car was chosen as the parameter for evaluating compatibility performance. Simulation of vehicle-to-vehicle crash in conditions of different stiffness, geometry height and overlap ratio were developed by using LS-DYNA. From the simulation results, it can be found that the influences of the frontal stiffness and geometry height on the compatibility are discrepant at different overlap ratios. The compatibility performance of the two vehicles could be improved by controlling the front stiffness and geometry height reasonably.

Research on the Effect of Rear Seat Structure on Child Occupant Safety

This paper aims to study the effect of the rear seat structure on child occupant protection. According to GB15083-2006 standard, a finite element model of luggage cabin and rear-row seat was developed in LS-DYNA and validated via test results. The model was used in analysis of the safety performance of rear seat structure under luggage impact in car frontal crashes, in order to minimize the risk of child occupant injury. A 3 years old child seat was simulated with fixing on the rear seat. Four optimization schemes were designed in order to reduce the intrusion and acceleration of the rear seat structure, comparing to the original model. The original model was improved via the structure optimization of rear seat, as well as the fixed positions of child seat. A verification model is developed to simulate rear seat impact with combined optimization schemes. The final results from the verification model show that the intrusion and acceleration of rear seat structure are all much smaller than original seat model.