Abstract: To improve the stiffness of a gun's top carriage, an modified design was conducted by using the structural optimization based on the path of force transmission. The static stiffness and strength were calculated by using the finite element method, and the weak links in the original design were analyzed. The topology optimization was used to find the main path of force transmission and search for the best material distribution, and then the layout of stiffeners was modified. The detailed design was accomplished by using size optimization, and the thicknesses of major plates were determined. The stiffness and strength of the improved top carriage were enhanced after optimization, the maximal displacement reduced by 32.7%, the center variation of trunnion chamber declined by 52.1%, and the maximal stress decreased by 20.0%, while the mass only increased by 1.9 kg. The results show that the expected goal is achieved.

Key words: mechanical design, top carriage, topology optimization, size optimization, path of force transmission