Evaluating Pedestrian Head Sub-system Test Procedure against Full-scale Vehicle-pedestrian Impact Using Numerical Models

Chen, Huipeng, Mechanical and Aerospace Engineering - School of Engineering and Applied Science, University of Virginia
Panzer, Matthew, Department of Mechanical and Aerospace, University of Virginia

Head injury is the primary cause of pedestrian fatalities. To address this problem, the simplified sub-system test procedure has been used to distinguish vehicle stiffness in recent decades. Compared to the full-scale dummy test, the sub-system test has the advantage in terms of cost, repeatability, and testing coverage. However, the sub-system test methodology has long been criticized for oversimplification and for missing head-neck interaction, vehicle pre-deformation, and head rotational kinematics, which make the ability of the component test to represent the real full-scale impact questionable. As a result, a potential problem may exist because vehicle design is optimized towards the sub-system test but may not necessarily provide the best protection in real pedestrian accidents. The goal of this dissertation is to study the relationship between the impactor responses of sub-system test with the head response in full-scale pedestrian impact. This process involved multiple steps: 1) evaluate the biofidelity of the PFEM; 2) compare the impactor response in the sub-system test and head response in the full-scale impact; 3) test the hypothesis that vehicle design variations have different influences on the impactor response and head response; and 4) investigate the factors that may contribute to the difference between the component test and the full-scale impact. The results of this work demonstrate limitations in the sub-system test that prevent it from reproducing the full-scale head response, even with matched input kinematics. Many of the limitations of sub-system tests were focused on the lack of vehicle hood pre-deformation caused by the pedestrian torso. The methodology and results of this dissertation could provide reference for improvements to future vehicle safety design and pedestrian regulation development.

PHD (Doctor of Philosophy)
Pedestrian, Sub-system test, Impactor, THUMS
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