Biofidelity evaluation of AC-HUM pedestrian model based on generic sedan Buck model

Objective: This study aims to evaluate the biofidelity of the Advanced Chinese Human Body Model (AC-HUM) by utilizing a generic sedan Buck model and postmortem human subjects (PMHS) tests. Methods: The boundary conditions of the simulation are derived from the PMHS test with Buck vehicle. The methodology involved the pose adjustment of the upper and lower extremities of AC-HUM, executed through a pre-simulation approach. Subsequently, a 200 milliseconds full-body pedestrian crash simulation was conducted by integrating the Buck vehicle model with the AC-HUM pedestrian model. The trajectories of AC-HUM during the period from initial position to head impact were recorded, including the Head CG, T1, T8 and pelvis. Based on the knee joint, the biofidelity corridors of trajectories in PMHS test were scaled to match the Chinese 50th percentile male to assess the biofidelity of AC-HUM's motion trajectories. Furthermore, the biomechanical responses and injury prediction results of AC-HUM were compared with the PMHS tests, including injuries of head, chest, lower extremities and pelvis. This comparison comprehensively evaluates the AC-HUM pedestrian model's capability in predicting injuries under whole-body pedestrian collision scenarios. Conclusion: The results of The comparison of the tracks reveals that the motion trajectories of all four markers of AC-HUM were located within the PMHS trajectories corridors, confirming that the AC-HUM pedestrian model demonstrates good biofidelity. Additionally, the injury prediction data from various regions of AC-HUM indicate that the model accurately replicates biomechanical responses, suggesting that AC-HUM holds significant potential as a human injury prediction and evaluation tool in virtual vehicle safety assessments in China.