Crashworthiness Simulation Analysis Of The Car Rear-end Rubbing Beam In Low Velocities

Recent traffic accident statistics showed that the casualties resulted from rear-end collision, which was one of the main traffic types, were most. Therefore the research on the crashworthiness of car rear-end rubbing beam was important for car structure and crew safety.In this paper, three-dimensional geometric model of rubbing beam system was established with Solidworks according to a car. It was imported into LS-DYNA and made some repairs. The main parameters, which affected the efficiency and accuracy of the simulation, were selected to establish the finite element model of the beam. The pendulum body was built according to GB17354-1998 regulations, which also affected the setting of the solution parameters. The overall model was established successfully and its simulation was finished by LS-DYNA, which had strong nonlinear solution function. The response for the deformation, displacement of the bumper was obtained to evaluate its crashworthiness. In the collision, most of the energy was absorbed by the plastic deformation of the bracket. So the impact of different bracket's structural parameters on the crashworthiness was analyzed and the theoretical basis for designing better rubbing beam was presented. The main conclusions were as follows:1. The position of the bracket had a great effect on the crashworthiness of the beam. The displacement of the beam was minimum, only 11.459mm, and its energy absorption capacity was best when the bracket was decorated on the central beam. The collision was finished on 14ms and the energy absorption of the central beam by plastic deformation didn't play a role. The displacement of the beam was maximum, 109.205mm, while the collision wasn't over. And its energy absorption capacity was worst when the bracket was deployed on both ends of the inclined beam. So the bracket should be arranged between the two locations and the specific locations depended on the cars.2. The simulation of three forms of bracket section was implemented. The results showed that the bracket section should be designed rectangle, of which square section was best in absorbing energy.3. The simulation of the thickness, which was set four groups, of beam was carried out. It was cleared that with the thickness increasing, the beam energy absorption ability increased gradually and the displacement decreased.4. Cone brackets were designed which contained three groups of cone angle. Their failure mode was closer to symmetrical telescoping type, which had better energy absorption ability compared with straight structure. When cone angle was 1°, it didn't have significant effect on the crashworthiness of the beam. But if the cone angle was too large, the energy absorption of the bracket would be weakened. So the cone angle should be arranged between 2°-3°.5. The slot was grooved on the bracket which was simulated. The slot would weaken the strength of the bracket. But the beam had better energy absorption ability compared with which wasn't grooved.