Study On Body Deformation And Energy Absorption Characteristics Of Vehicle Side Under Blasting Loading

At present,the anti-explosion research of vehicle mainly focuses on the bottom protection of military vehicles.However,with the widespread occurrence of terrorist attacks and accidental explosions on roads,civil vehicles,including a police car and a banknote truck,have also been seriously affected.Therefore,the thesis studied the body deformation and energy absorption characteristics to guide the anti-explosion design of the vehicle structure.First,based on the finite element theory and LS-DYNA theory,it established the finite element model(FEM)of vehicle under side blasting loading in Hyper Mesh by CONWEP method,including FEM of vehicle,explosion shock wave model and contact and output control.Through partial test and energy analysis of the simulation system,it is proved that the model is effective and can be used to the anti-explosion analysis and improvement research.Secondly,based on the damage principle of explosion shock wave,it analyzed the deformation,deformation mode,energy absorption process and intrusion velocity of the body and the key parts of body including vehicle door,B/C-pillar and roof and so on.The results show that the intrusions of front and rear door,B-pillar,C-pillar and roof are respectively as high as 232,344,309,380,250(mm);their peaks of intrusion velocity are 53.357,46.622,28.455,37.417,18.743(m/s);and their energy absorption efficiencies are low to 2.877,1.616,1.174,1.061,0.581 [J/(kg*mm)].It shows that the body deformation is serious and the window glass is broken.Therefore,the occupant safety is poor.Then,the thesis aimed at the problems of characteristic analysis to design an improving scheme and repeated simulation,which improved the sealing capacity of body structure,the body strength layout and the energy absorption structure.The results show that the intrusions of front and rear door,B-pillar,C-pillar and roof are respectively reduced by 34.91%,23.84%,44.34%,31.05%,54.40%;their peaks of intrusion velocity are reduced by 27.28%,-0.85%,19.52%,21.78%,and 27.34%;and at the same time,their energy absorption efficiencies are increased by 4.10%,4.83%,5.03%,43.07%,and 70.22%.Although the peak of intrusion velocity of the rear door has a slight increase,its duration is greatly shortened.It shows that the body deformation and energy absorption are improved and the window glass is not falling.Therefore,the occupant safety is greatly improved.So it is proved that the characteristic analysis is correct and can guide the anti-explosion improvement design of the vehicle structure.Finally,based on uniform experimental design,the thesis studied the influence of the initial conditions.It selected 5 combinations of initial conditions to simulate.Then it analyzed comprehensively their deformation mode and energy absorption process,and carried out the multiple linear regression analysis to the intrusion and final deformation of the center point of B-pillar.The results show that the initial conditions have great influence and the Y coordinate of TNT have the most significant influence.However,the body deformation and energy absorption characteristics are in good agreement under different initial conditions.Meanwhile,the obtained regression equations can be respectively used for prediction of the anti-explosion performance of the vehicle and analysis of the explosion accident.In summary,this thesis studied the body deformation and energy absorption characteristics of vehicle side under blasting loading,and then designed an improving scheme of the body structure and researched the influence of initial conditions.The results show that its analysis method is correct,the improvement effect is excellent and the regression equation is reliable.Therefore,it has good reference value.