Abstract: In order to improve cab acoustic characteristics, the structure-acoustic coupling finite element model of the cab is established at first. Frequency response analysis is then performed to get the interior acoustic response. The acoustic structural modal participation factors and panel acoustic contributions for peak sound pressure at 81 Hz are computed to find structural modals and panels that have most influence on the acoustic response of vehicle. Those panels are treated with damping material. In order to find the optimum distribution of damping material and reduce its consumption, the topology optimization program based on optimization criteria algorithm is written using direct matrix abstraction program(DMAP) language, with maximum modal damping ratio of cab as goal, damping material volume as restriction and densities of damping cell as design variables. After optimization, the volume of damping material is down to 60%, while the modal damping ratio is lowered to 94.8%. According to the optimization result, damping material is added to the cab. The pressure near driver’s right ear and passenger’s right ear at 81 Hz is reduced 11.2 dBA and 10.7 dBA. Other peak sound pressure changes little.

Key words: Cab, Damping, Finite element method, Structure-acoustic coupling, Topology optimization