A finite element model for a SUV body-in-white is established and a simulation on its static stiffness and mode distribution is conducted to improve its vibration performance. Then key body panels are selected by sensitivity analysis with their thickness as optimization variables, the torsion stiffness and the mass of body are taken as objectives with their radial base function models built, the static stiffness, the frequencies of 1st order torsion and 1st order bending modes are chosen as restraints, and an optimization on body performance is carried out with multi-objective genetic algorithm. Finally the key body panels optimized are trail-produced for modal test, verifying the rightness of optimization results. After optimization the overall stiffness of car body is increased and the distribution of modal frequencies is improved while the total mass of car body slightly rises (0.55%). The peak values of transfer function at the mounting points of left and right rear seats fall by 47.50% and 49.37% respectively, greatly improving the vibration performance of car body and laying a good foundation for enhancing the NVH performance of vehicle. © 2017, Society of Automotive Engineers of China. All right reserved.
