Lightweight design of body-in-white based on agent model
（1. School of Mechanical Engineering， Nanjing University of Science and Technology， Nanjing， Jiangsu 210018， China； 2. Nanjing Iveco Automobile Co., Ltd.， Nanjing， Jiangsu 211800， China）
Abstract：To solve the problem that the traditional finite element method could not effectively realize the weight reduction of bodyinwhite, the proxy model technology was applied for the modeling and optimization design of the bodyinwhite system to realize the global weight reduction under the constraints of stiffness and modality. 16 key components were selected from the bodyinwhite， and the thirdorder response surface model， the radial basis function model and the Kriging model were constructed with the component thickness as design variable． The fitting accuracy of the proxy model was compared．With vehicle mass and firstorder torsional modal frequency as goals, the NSGAⅡ algorithm was used to optimize the multiobjective thickness of key parts．The optimized bodyinwhite was tested for stiffness modality and surface anticoncave performance．The results show that the thirdorder response surface model has the best fitting precision. The weight loss of the final body is 11.5 kg, and the bending and torsional rigidity of the vehicle body are respectively increased by 1.8% and 1.1%. The anticoncave stiffness of the side panel midplate surface is decreased by 7.8% without exceeding the safe range.
