Evaluation Of Effectiveness Of Head Injury Criteria Based On VRU Impact Accident Reconstruction

With the rapid development of the automobile industry,the number of domestic passenger cars continues to grow.While automobiles bring convenience to people’s daily life,the number of traffic accidents is also rising,and road traffic accidents have become a major public hazard threatening human life safety.During a collision with a vehicle,vulnerable road users(VRU)such as pedestrians and two-wheeled bikers lack adequate protection measures,and their lives are greatly threatened.In the road traffic accident injuries,traumatic brain injury is the main type of injuries and the main cause of fatal injuries.Therefore,it is of great practical significance to study the biomechanics of craniocerebral injury.In order to reduce the risk of craniocerebral injury in traffic accidents and other dynamic impacts,predecessors put forward different evaluation criteria for different types of head injuries through a large number of studies.Although the predecessors have done some research on the ability of injury criteria to predict the risk of head injury,there are still some limitations in the research methods,which mainly lie in: The multirigid human body model can only output the damage parameters based on head kinematics,but can not obtain the damage parameters of brain tissue;Adopting finite element human body has high time cost and low adjustment flexibility;Using the finite element human head model alone ignores the influence of the torso on the head injury.Based on the road traffic accident investigation database IVAC(The In-Depth Investigation of Vehicle Accident in Changsha),this paper first screened out 31 VRU traffic accidents with complete accident information and detailed human injury information,and the traffic accidents are reconstructed based on multi-body kinematics by using multi-rigid-body software MADYMO.Comparing the kinematic response,collision point,collision position and final stop position between vehicle and VRU between real accident and simulation,the simulation results are consistent with the accident information,and the error range is controlled within 10%.After the accident reconstruction is completed,the MB human body model is replaced by the coupled FEMB human body model,and the simulation calculation is carried out again to complete the reconstruction of human head injury.A pedestrian accident and a bicycle accident are used to demonstrate the above process.Repeat the above process to complete the multi-rigid accident reconstruction and human head injury reconstruction of all 31 VRU collision accident cases,laying the foundation for the follow-up study of the prediction ability of the head injury criteria.Based on the results of accident reconstruction and human injury replication,the head injury of VRU in each case is analyzed,and the parameter value of head injury criterion is calculated.The Pearson correlation coefficient analysis method is adopted to investigate the correlation between head kinematics-based injury criteria and the actual head injury of VRU;the effectiveness of brain deformation-based injury criteria in predicting typical brain injuries(such as diffuse axonal injury DAI and contusion)is assessed by using head injury risk curves reported in the literature.The above research results based on the reconstruction of the real VRU collision accident and the reconstruction of the brain injury show that: for head kinematics-based injury criteria,the most widely used head injury criteria(HIC)and head impact power(HIP)can accurately and effectively predict head injury,whereas for brain deformationbased injury criteria,maximum principal strain(MPS)behaves better than cumulative strain damage measure(CSDM0.15 and CSDM0.25)in predicting the possibility of DAI.Compared with the dilatation damage measure(DDM),MPS seems to better predict the risk of brain contusion.