A Study On The Dynamic Response And Injury Of Cyclist On Vehicle-bicycle Accident Reconstruction

In China,cyclists as vulnerable road users,represent a population with high risk of fatal and severe injuries in mixed traffic environment.Compared with other two-wheeled vehicles(such as motorcycles,electric vehicles,electric bicycles,etc.),bicycle cyclists have the highest mortality rate in traffic accidents.Therefore,it is of great significance to carry out damage analysis and damage protection for cyclists in China.In this paper,273 cases of automobile-bicycle accidents in the CIDAS database have been collated.Descriptive statistical methods have been used to describe the laws of bicycle accidents and the injuries of cyclists.The data show that:the intersection is the main area of frequent bicycle accidents,the frequency of accidents on the straight road is the second;male cyclists in bicycle accidents account for the majority;head injury and lower limb injury are two major injuries for cyclists;the passenger car is the main type of accident for a bicycle accident and accounts for 65%of the total number;The car-bicycle accident pattern is dominated by automobile side collision bicycles,and this type of accident accounts for about 44%.Then,bicycle,cyclist and car models were built by PC-Crash software and used for accident simulation experiments.The impact of bicycle seat height of bicycle on the cyclist's head and lower limbs in a typical crash is analyzed,the cyclist's HIC value and lower limb contact force curve are output,and a mathematical model is established.Finally,74 cases in the CIDAS database are finally verified.The reliability of bicycle accident reconstruction results validates the model.The results show that the influence of the height parameters of the seat height of bicycle on the cyclist has different characteristics under the influence of the vehicle type;under different collision angles,the cyclist's dynamic responses corresponding to different seat heights of bicycle are different;the cyclist's head is different;The cyclist's risk of head injury and the risk of lower limb fractures are related to the height of the bicycle seat.Finally,79 cases of car-bicycle accidents are selected from the CIDAS database for analyzing the effect of sitting posture on the dynamic response of the head in the actual case.Grouping four postures to establish a mathematical model of the relationship between head crash speed,wrap around distance(WAD),degree of injure and vehicle speed,and further study the risk of head injury to cyclists and compare the differences between different postures..The results show that the dynamic response of the cyclist's head is affected by the riding posture;there is a strong correlation between the head collision speed,the WAD,the degree of injury and the riding posture;The risk of AIS 3+ injury is related to riding posture and crash speed.In summary,This paper takes the car-bicycle accident as the research object,based on the field investigation of the car-bicycle collision accident,the bicycle structural parameter and the bicycle cyclist's posture to study the injury factors and casualties risk of the cyclist.The main contents include:(1)Classifying and statistics of 273 car-bicycle accidents in the CIDAS database;(2)The bicycle and cyclist models are established,and the multiple rigid body models of the bicycle and the cyclist are adjusted respectively so that the bicycle has corresponding structural parameters and the cyclist has a corresponding riding posture.PC-Crash was used to reconstruct 79 car-bicycle crashes and to classify and count the injuries of cyclists;(3)Based on the theoretical mathematical model method,the structural parameters of the bicycle and the riding posture of the rider in the car-bicycle collision accident were studied respectively;(4)Combining with logistic regression,establish a correlation model between the degree of injury of the cyclist and the vehicle speed,bicycle parameters and cyclist's posture,and evaluate the rider's AIS3+ risk curve.