Injury Mechanism And Prevention Research Of The Driver's Lower Limb Injury In Minibus Frontal Collisions

China is one of the world's largest road traffic fatalities countries.Accidents caused huge economic losses each year,the same time,it also brought a heavy blow to people's spirit and life.Minibus is characterized by multiple,large space and low prices.So this models are popular with people in rural areas.But the minibus body strength is weak.After vehicle collision,the minibus body structure deformation generally higher.This often leads to serious damage to the vehicle occupants.Therefore,a comprehensive and detailed mini-van accidents in-depth investigation is very important.Through in-depth investigation of the minibus accident,we can analyze the causes of traffic accidents,human injury mechanism analysis,vehicle safety analysis and put forward reasonable proposals for the traffic safety management.Since the research focuses on lower extremity injury to the driver,so we have to focus on detailed driver injury case.And the types of accidents should be minibus head-on collision.After statistics on accident types,we found that the type of accident statistics from more to less are : minibus collision with pedestrian,collision with motorcycle,collision with the truck,collision with cars,collision with the bike,collision with fixed barrier and other types of accidents.Among them,the type of minibus collision with truck is ideal for research.This type of accident include minibus rear-end truck and minibus head-on collision with truck.In the accident of minibus head-on collision with truck,both vehicles have the initial velocity.Driver's risk of death is high.While in the minibus rear-end truck accidents,the collision speed is relatively low.In this paper,we while choose the minibus rear-end truck accident for research.This study aims to elucidate the biomechanical mechanism of a driver's lower limbs injury by establishing simulation models of minibus rear-end trucks.First,a seat belt finite element(FE)system is established in a minibus FE model.Then,the minibus FE model and the total human model for safety(THUMS)are utilized to rebuild two colliding conditions: a minibus rear-end truck and a minibus head-on rigid wall.The speed in the two collisions is 56km/h.Comparisons were made as regards the vehicle dynamic response,vehicle deceleration,dashboard intrusion distance in the two collisions.In the minibus rear-end truck collision,the von Mises equivalent stress peak of the tibia and the femur is133 and 126 MPa.In the minibus head-on rigid wall collision,the von Mises equivalent stress peak of the tibia and the femur is 139 and 99 MPa.Comparison of the two colliding conditions reveals that the vehicle deceleration is smaller and the dashboard intrusion is larger in the minibus rear-end truck collision than in the minibus head-on rigid wall collision.The results illustrated that a longer dashboard incursion distance corresponds to a higher the von Mises equivalent stress in the femur was.These simulation results are consistent with a driver's autopsy report on lower limbs injuries.These findings verify that FE simulation method is reliable and useful for analyzing injury mechanisms.In the rear-end truck collision,the truck tailgate and the rear carriages are high,causing the main energy-absorbing parts of the minibus to be located at a higher position.These parts typically consists of the engine hood,the engine compartment,the A-pillar,and so on.Given that the structural strength of these parts is lower than that of the front bumper and the frontal longitudinal beam,the dashboard intrusion becomes greatly increased.The excessive intrusion of the dashboard is the main cause of the driver's femur injuries.Therefore,reducing the height and built-in distance of the truck tailgate,as well as increasing the structural strength of the engine compartment and A-pillar of the minibus,are all useful in protecting the driver's limb from injuries.Another effective approach is to install a high bumper at the front of the minibus.FE simulation technology is playing an increasingly important role in the reconstruction of the traffic accident.It has become the main methods for a scholar to explore the biomechanical mechanism of traffic injuries and to carry out related research.Meanwhile,it also has a strong advantage in the exploration of vehicle safety.