Lightweight Design of Patch Plate on Car-body B-pillar based on Side Impact Safety

The B-pillar of automobile needs to meet the requirements of vehicle strength and rigidity, and also consider the fuel economy of vehicle. Therefore, the design and development of B-pillar is a difficult point in the field of car body design and manufacturing. Based on the side impact regulations, the safety model ling and simulation analysis of the B-pillar of the vehicle was carried out to obtain the change law of the intrusion amount and the intrusion speed of the five key points in the whole process. According to the analysis results of side impact of B-pillar, a scheme to reduce the material thickness of B-pillar body and increase patch plate for lightweight design was proposed, and a comparative analysis of the safety of side impact was made. In view of the problem that the intrusion of B-pillar of a real vehicle model did not conform to the regulations, the design scheme of adding patch plate was proposed to improve the safety of side impact. According to the actual collision results, the simulation model was modified, and the design scheme was simulated and optimized. The reliability of the design scheme was verified by the real vehicle collision analysis. The results show that: in the side collision of B-pillar, the intrusion of D2 position measurement point is the largest, the intrusion velocity of D3 position measurement point is the largest, and the intrusion amount and intrusion speed of D5 position measurement point are the smallest. Patch plates are added to the inner side of adjacent area of D2 position measurement point. The welding point is welded with B-pillar structure, and other areas of B-pillar keep the same structure, so as to realize lightweight and effective improvement of safety. Under the condition of maintaining the original material and thickness of B-pillar, two patches with thickness of 2 mm and material of B340LA are added in the middle of B-pillar to improve the structural strength. The defect area is set at the wrinkle position of the original B-pillar to guide the deformation mode of the B-pillar. The relative deviation between simulation calculation and test intrusion is less than 20 %, and the car crash simulation model with improved B-pillar structure is more accurate. For this type of car, the optimization and improvement effect of B-pillar structure is ideal, which improves the passenger safety protection ability in side impact.