Stiffness Optimization And Lightweight Of B Pillar Based On Foam Aluminum

Side collision of auto-mobile bringing about the more serious losses is one of the styles of conventional crash accidents. As the significant part of car body, B pillar plays a momentous role in receiving and delivering impact loads when side collision accidents occur, because of its crashworthiness closely relating to protection of passengers and side collision safety of auto-mobile, improving its crashworthiness has far-reaching significance and need to be studied. As a new kind of material, foam aluminum with many favorable characteristics such as low density, high specific strength and excellent energy absorbing capability has been successfully used in the auto-mobile field. Therefore, filled B pillar with foam aluminum can achieve improvement of its crashworthiness.The B pillar of a car as the research object was studied and referring to C-NCAP criterion full vehicle side impact finite element model was established. Firstly, through the analysis of the energy curves and added masses curve, the creditability of the model was validated. Secondly, deformation of B pillar, incursion quantity curves and incursion velocity curves of B pillar were extracted and analyzed in detail.First of all, body-centered cubic unit cell model of foam aluminum was established according to ideal assumption. Considering interaction force between unit cell and unit cell in the compression process, body-centered cubic of foam aluminum structure with 27 unit cells was chose to use to study. Finite element simulation of quasi-static axial compression of foam aluminum was accomplished by using LS-DYNA software. The results of energy curves analysis and compared with existing experimental data showed that the structure that was established in the paper was effective. Then, with the help of simulation, the compression mechanical properties and energy absorption properties of foam aluminum were analyzed in detail. Finally, hollow circular aluminum tube was filled with the emulated foam aluminum whose porosity was 76%. In contrast with the hollow circular aluminum tube, the results of energy absorption and compression displacement showed that structure filled with foam aluminum has the excellent effect of energy absorption.Foam aluminum was filled in the B pillar. Using methods of orthogonal test and multi-factor weight optimization method and combining with the simulation results of foam aluminum parameters. Porosities of foam aluminum, substrate materials and thickness of B pillar were taken as design variables. Incursion quantity and incursion velocity were regarded as evaluation index. Finally the best combination of B pillar was achieved and the optimized design of B pillar was realized. Optimization results showed that stiffness and energy absorption of B pillar that filled with foam aluminum improved greatly while its mass reduced in the side collision. It provided feasibility reference for design of side impact resistance of vehicle.