Crashworthiness analysis and multi-objective optimization of spatial lattice structure under dynamic compression.

• Lattice structure of honeycomb is proposed to improve structural crashworthiness. • Four single-cells of lattice structures (different Poisson's ratios) are considered. • Effect of basic parameters of single-cell on structural crashworthiness is discussed. • Multi-objective optimization method is proposed using GRA coupling EW. A spatial lattice structure is proposed to improve the structural crashworthiness and energy absorption. First, a single-cell structure is proposed via a bionic honeycomb, and then the single-cell structure is arrayed to form a spatial lattice structure. The finite element model of the spatial lattice structure for crashworthiness analysis is established. The theoretical model of the plateau stress of the lattice structure under compressive conditions is derived, and its accuracy is verified by the corresponding finite element analysis. After that, the effect of geometrical parameters of single-cell structure on crashworthiness is analyzed. Then, geometrical parameters of single-cell structure and number of single-cell in the X, Y , and Z directions are used as design variables, the mass, and overall size are used as constraints, and specific energy absorption and collision peak force are used as optimization objectives. The multi-objective crashworthiness optimization of spatial lattice structure is carried out, and the optimal lattice structure design is determined via the gray relational analysis coupling entropy weight method. The validity of the finite element model and optimal design is verified by the drop weight impact test. The crashworthiness optimization of spatial lattice structures has important guiding significance for the design of energy-absorbing structures. [Display omitted] [ABSTRACT FROM AUTHOR]