Multi-objective Optimization Design Of B Pillar Of Vehicle Body Based On Function Orientation

Automobile body is a complex assembly composed of thousands of parts,accounting for about 40% of the total vehicle mass,which is the main direction of automobile lightweight.Body weight reduction is carried out on the premise of ensuring the comprehensive performance of automobile such as stiffness strength,NVH and collision safety.It involves multiple disciplines such as collision,NVH and aerodynamics,and requires us to use multi-objective and multi-disciplinary collaborative optimization,namely multi-objective optimal design(MOP).In the number of body parts,due to different function of each parts,and components under the same function the role of the size is different also,so the key point of each component design goal is different,this needs us to use Benchmark to functional division of the body parts,then regional sensitivity analysis,find the index has significant effect of the key parts of the car body,and then to function as the guidance,to the key area of the car body corresponding target under multidisciplinary optimization design.This paper introduces the design process based on the function of body and body areas that give the building method of simplified mechanical model,and then based on the Benchmark for the performance of the car body decomposition,find key areas,which has the function of a certain body finally establish body areas that the multidisciplinary optimization design method,a whole set of body design process based on function orientation.Among the numerous automobile body components,b-column,as an important body structure,not only requires light weight,but also requires sufficient stiffness.In the case of side collision,the collision deformation can be reduced so that the driver has enough living space and safety.Based on car B column as analysis object,this paper established the finite element model of collision column B,with B the column plate,plate,the thickness of the reinforcement plate as design variables,B column and dosage into the quality of the collision performance index as the optimization goal,a multidisciplinary optimization model is established,on the collision analysis,use of genetic algorithm to solve the B column within the board,plank,reinforcing plate thickness of the optimal solution of 1 mm,1.4 mm and 1.2 mm respectively,and the rationality of the simulation result is verified by experiment.By comparing the results before and after optimization,it is found that the total mass of B column is reduced by 7.1%,and the intrusion amount of B column is reduced by 26.4% under the condition of side impact,which indicates that the optimization not only greatly improves the side impact safety of B column,but also achieves a certain weight loss effect.Therefore,the multi-disciplinary optimization design method based on the function oriented key area of the vehicle body strengthens the key parts according to the function of the body parts,which not only reduces the optimization design cost,but also ensures the optimization efficiency,which is of great significance to the optimization design of the vehicle body.