In order to improve the static and dynamic performance of railroad passenger cars and meet the needs of lightweight

this paper takes the 25T passenger carbody as the research object

the multi-level topology optimization strategy is established based on modal analysis

and a multi-objective topology optimization model considering static and dynamic performance is established by using compromise programming method

and the weight coefficients are determined by analytic hierarchy process (AHP)

the carbody is optimized first as a whole and then in a sub-regional local topology optimization. The results show that the frequency of each low order elastic mode is increased

in which the frequencies of the first order rhomboid and the first order vertical bending mode increase by 0.74 Hz and 0.30 Hz

respectively; the mass of carbody decreases by 196.7 kg

and the maximum stress on the carbody decreases by 7.03%. It is shown that the multi-objective optimization under the multi-level topology optimization strategy is feasible and effective for improving the performance and lightweight of the railroad passenger carbody.