Abstract: To solve the design problem of heavy commercial vehicle chassis， a global topology optimization method based on multi-load conditions and quatric local-optimization was proposed. A structural topology model was constructed based on the real sizes of commerical vehicle chassis. A preliminary topology structure was obtained based on seven typical loading conditions of the vehicle， and the final chassis optimization structure was obtained with the quatric-topology-optimization method based on different loading conditions. Finally， the finite element validation was given. The results showed that the new chassis mass reduced by nearly 30kg， and its stiffness， intensity and modal quality improved to a certain extent compared to the current one， and the effectiveness of the proposed quatric-topology-optimization method was verified.

Key words: commercial chassis, multi-load-condition topology optimization, quatric-topology optimization, finite element validation, lightweight