A Safety Study On The Structual Improvement And Optimization Of The Roof Collision For A SUV Car

The frequency of the rollover collision is lower than the other traffic accidents, butthe death rate is the highest. When the rollover occurs, the occupant’s head impacts thedeformed roof leading to the occupants’ head and neck injury or death. The lower roof’sstrength is the direct cause of death. As more and more people pay attention to automobilesafety, the occupants’ security of rollover collision has been taken seriously. Our countryreleased “Roof Crash Resistance of Passenger Cars” on January14,2011according to theFMVSS216of United States. It uses the experiment of roof quasi-static crush to study theroof’s crashworthiness.The object of study is a SUV model according to the “Roof Crash Resistance ofPassenger Cars”, the accurate finite element model of roof crash is built in theHYPERMESH. The software of LS-DYNA is the solver. The software of HYPERVIEWand HYPERGRAPH is the post-processing. The validity of the model is verified by massscaling, energy analysis, and numerical stability analysis.To find out5side parts which have main influence on the crashworthiness of roof, asensitivity analysis has been done by the range analysis method of orthogonal experiment.According to examining the figure of the deformation, the joint between the A pillar innerplate and hinge pillar reinforcement has been changed, improving the joint stiffness and Apillar inner plate’s bending stiffness. At last, the crashworthiness of roof has beenimproved.The side5main parts have been optimized by ISIGHT. In the optimization schemes,the optimization objective is the maximum resistance force and the constraint condition isthe maximum total mass of the optimization parts. The optimization method adopts theapproximation models. The first optimization scheme for thickness and high-strength steelis reasonable allocation of structural stiffness. The second scheme for the B pillarreinforcement adopts the method of laser tailor-welded plate, which is divided into fourparts, optimizing the thickness of each part. The validity of the second scheme is verifiedby the model of side collision. The validity of the optimization results are also verified. Eventually, the maximum resistance force is2.56times that of the weight of the vehicle.So it achieves the goal of this study.