Abstract: In the optimization design of the free damping layer of the vehicle body panel, a robust optimization design method considering uncertain fluctuation of damping material parameters is proposed. Firstly, damping materials are full-coated on the body areas such as firewall, floor and ceiling. Secondly,topological optimization of the damping layer layout is carried out taking the equivalent radiated power (ERP) as the optimization objective and the optimization effect is verified. Finally, the six sigma robust optimization design of the damping layer is carried out by taking the thickness of the damping layer as random design variable, the loss factor and elastic modulus as random variables, and the minimum mass as optimization objective, and combining the radial basis function (RBF) approximation model, Monte Carlo simulation (MCS) and sequential quadratic programming (SQP). The results show that the total mass of the free damping layer is reduced by 50.45% after optimization, and the noise performance of the body structure reaches the six sigma quality level, which achieves the goal of robust optimization of the damping layer under the requirement of lightweight body

Key words: vehicle interior noise, free damping layer, equivalent radiated power, robust optimization, lightweight