Biomechanical Study On The Injury Of Long Thin-walled Tube Penetrating Into Passenger’s Chest And Lung

Car guardrail in the impact,the bar and vertical bar connection is easy to break,the bar in the collision process of the formation of thin-walled long pipe and through the car engine compartment or front windshield.According to the observation results of the accident of vehicle collision isolation guardrail,the thin-walled long tube is easy to penetrate the chest of the driver and the passenger in front,causing serious fracture of chest ribs and damage of internal organs,leading to massive bleeding.At present,collision experiments at home and abroad mainly study the damage and related mechanical response of blunt objects after collision with human chest,while there are few studies on the penetration of long tubular objects through the chest.However,in actual traffic accidents similar to the guardrail through the human body frequent accidents,it is urgent to study the corresponding penetration injury.Firstly,this paper uses the chest CT of an adult male from the 50 th percentile of China to carry out body modeling.Mimics,Geomagic and Hyper Mesh software are respectively used to extract the model,reduce noise,materialize and divide mesh.The reliability of the model was verified by the simulation of three-point bending load of human ribs,the simulation of front and rear loading of human ribs and the simulation of frontal collision of human chest.The simulation results show that the model is reliable.Then fixed human body model,centered on human body chest sternum,clockwise counterclockwise 30 °,from left,middle and right three directions at low speed,medium speed,the speed of the three different impact human body chest model,simulate the real traffic accident car crash barrier after the pilot was cross bar through the chest of the scene,the chest lung damage,which is the main organ The injury mechanism and mechanical response of lung were analyzed.The mechanism of injury is that in frontal impact,the thin-walled long tube impinges on the sternum,and the sternum drives the costal cartilage and ribs to compress the costal surface of the lung,resulting in the injury of the costal surface of the lung.In the side impact,the thin-walled long tube impacted the ribs and caused fracture.The damaged ribs penetrated into the costal surface of the lung together with the thin-walled long tube,causing severe lung damage.At the same time,the lung injury at different penetration depth was investigated.The deeper the penetration,the greater the injury.The mechanical response of the lung depends on the Angle and velocity of the thin wall tube.The results of the simulation experiment can be used to study the injury mechanism of human chest viscera penetration injury in the safety of automobile collision.The parameters of human ribs in different ages are different,and the fracture and damage of the ribs under external force are also different.According to different age groups,therefore,the body frame of cortical bone parameters and relevant research results both at home and abroad,and to modify the key parameter of frame cortical bone,simulation of penetration when human body chest rib long thin wall tube damage and the mechanical response,get the key parameter of frame cortical bone changes on the long thin wall tube penetration when human body chest rib injury.The simulation results show that the cortical bone thickness and the ultimate stress have a great influence on the fracture injury caused by the thin-walled long tube penetration.The thicker the rib cortical bone thickness and the greater the ultimate stress,the less prone the rib fracture is.The elastic modulus of cortical bone has little effect on the fracture of rib.Even though the elastic modulus of the experimental group changed greatly,the change of rib fracture injury was small and almost negligible.The automobile crash safety regulations use chest deformation as the assessment standard of human chest injury,but this standard basically uses adult data,and lacks the data of middle-aged and elderly people.This simulation experiment is also helpful to further improve the chest injury standard of elderly people.Finally,the difference of the injuries caused by different types of thin-walled long tubes was investigated.The structure of the thin-walled long tube head,namely regular opening and special-shaped opening,was analyzed.The study showed that the regular opening was unstable when penetrating,resulting in larger wounds and serious bleeding of the occupants.The profiled openings are more stable in penetration and therefore more penetrating,resulting in greater internal damage to the occupant.The damage difference between the cross sectional area of the thin-walled long pipe and the occupants is analyzed.The research shows that the thin-walled long pipe with a larger cross sectional area has a larger mass and a larger kinetic energy at the same speed,so the greater the damage to the occupants is.The research results provide some reference for improving the evaluation index of vehicle crash safety and optimizing the traffic guardrail.