FINITE ELEMENT ANALYSIS ON PLASTIC COLLAPSE BEHAVIOR OF TOPOLOGY-OPTIMIZED CELLULAR STRUCTURE SUBJECT TO COMPRESSIVE LOADING

The cellular structure is an assembly of cells. It may have excellent properties such as lightweight, high rigidity, and high energy absorption capacity with artificially manufactured cellular structure. However, guidelines for designing cellular structures with desired properties have not been established. This study aims to present the design guidelines for cellular structures with high energy absorption capacity. The unit cell was designed by topology optimization with the objective function of stiffness maximization. The compressive behaviors of the topology-optimized cellular structure and BCC, FCC lattice structures were investigated by carrying out the compression analysis by finite element method (FEM). A full model and a simplified model with a reduced number of cells with periodic boundary conditions were built for the analysis. It was confirmed that the use of the simplified model could significantly reduce the analysis cost. From the analysis results, it was shown that the deformation modes of the struts of the cell were different in optimized structure and BCC, FCC lattice structures. Finally, the specific energy absorption and the specific strength of each structure were evaluated. The optimized shape had high energy absorption capacity and specific strength compared with the BCC and FCC lattice structures. Further study is necessary to examine the objective function and boundary conditions in topology optimization to design cellular structures with larger energy absorption capacity by controlling the stress-strain relationships.