Study On Occupant Injury Based On Chinese Body Signs Under Blast Impact Condition

At present,the assessment of the damage status and damage mechanism of people in vehicles under explosion conditions is mainly studied by battlefield casualty statistics,body test based on simulated collision,real vehicle explosion body test and finite element model simulation.Among them,the real vehicle explosion corpse test is the most realistic and can obtain real human damage.However,due to the limitation of experimental cost and related human ethical issues,it is difficult to carry out the experiment in this aspect.After many considerations,based on the existing AEP-55 volume 2 regulations,combined with the general armored vehicle explosive equipment.The armored vehicle,dummy and human body are established as research objects,and the human body damage is studied by means of explosion simulation.The main research contents of this paper are as follows:1)Using Hypermesh pre-processing software and Smoothed Pa TIcle Hydrodynamics(SPH)algorithm without mesh,the finite element model of explosion impact was established.And by changing the Angle and thickness of the bottom plate two parameters to achieve the establishment of different explosion conditions,and to compare the difference of occupant damage in multiple conditions.2)According to the measured Chinese human body size and the scanned Chinese human body contour,the Chinese dummy model was established by using the whole segment scaling method on the basis of the existing mixed Ⅲ dummy model;Based on GHBMC-M50 model,the Chinese human body model was established by using grid scaling method.According to the relevant injury indexes of various parts of passengers stipulated in AEP-55 Volume 2,the dynamic injury differences of European and American passengers with human signs and Chinese passengers with human signs under multiple working conditions were compared and analyzed.3)In order to study the influence of muscle active force on lower limb injury,based on the Finite element model of Chinese human muscle active force,the explosion simulation considering muscle active force was carried out by setting corresponding activation parameters for the lower limb muscles in the model.The results show that the dynamic response and damage trend of the dummy and human finite element model based on Chinese human signs are basically the same as those based on European and American human signs under various explosion conditions.However,due to the ride attitude,the feet of European and American dummies and mannequins were closer to the explosion center,so the dynamic response of European and American dummies and mannequins was more severe than that of Chinese dumnequins,and the damage was more serious.The dynamic response,damage and damage difference of lower limbs in occupant model increased with the increase of floor Angle,but decreased with the increase of floor thickness.According to the tibia index results,the explosion impact has a great impact on the moment of the tibia,so that although the tibia axial pressure does not exceed the threshold,the tibia index exceeds the threshold,indicating that it is not comprehensive to use only the axial pressure to evaluate the tibia damage in the explosion condition.In the process of explosion,the introduction of the main muscle force reduces the axial pressure,increases the torque and increases the stress of the tibia,and increases the risk of stress concentration injury of the tibia.