Research On Impact Dynamic Response Of The New-type Height Restrition Barrier

Height restrition barrier is important safety facility for roads,bridges and tunnels.Recently,a number of carshes between over-high vehicle and height restrition barrier occurred resulting in serious consequences such as vehicle damage,passenger casualties,structure collapse,traffic jam,etc.Therefore,a new-type and prefabricated height restrition barrier based on the modification of old one is proposed in order to protect passengers.The main contents of this paper are as follows:(1)Finite element model of rigid height restrition barrier is established by LS-DYNA.A half-integral body bus model is selected from NCAC model database as the collision vehicle.The dynamic response and damage characteristics of vehicle and rigid limit height restrition barrier during collision are analyzed,which provides theoretical basis for the design of the new-type flexible height restrition barrier.(2)According to the above analysis results and the actual engineering requirements,the design concept and method of the new-type flexible height restrition barrier are proposed.The precise finite element model is established for collision analysis.The results show less damage of vehicle,passengers and structure from the aspects of energy,deformation,internal force,impact force and acceleration.(3)The most reasonable parameters of the new-type flexible height restrition barrier are designed by studying the influence of beam thickness,spring stiffness of the spring hinge support,mass and the speed of the vehicle.The component tests and vehicle collision tests are carried out.The results show its good applicability and effect in practical engineering.(4)A simplified collision mechanical model,three degree of freedom mass-spring model,is proposed and its dynamic differential equation is established.The parameters of this model are obtained through the quasi-static loading finite element simulation test.The comparison between the mass-spring model and the finite element model from the aspects of impact force and displacement shows its accuracy.