Topology optimization of microlattice dome with enhanced stiffness and energy absorption for additive manufacturing

Abstract

The synergy of additive manufacturing (AM) with topology optimization has become a useful method for developing ultralight, ultrastiff structures with high energy absorption capability. To improve the weight-specific stiffness and energy absorption capability of the conventional dome commonly used as the core of sandwich sheets, a new concept of filling the solid part of the dome with stretch-dominated microlattices is proposed. The optimal density distribution of microlattices is obtained by integrating the homogenization-based topology optimization method with the lattice structure. The compressive and bending stiffnesses of the optimized variable-density microlattice domes are demonstrated to be 41.8% and 33.7% higher than those of the conventional solid domes, while the energy absorption of the microlattice dome during compression and three-point bending is increased by 297.5% and 85%, respectively. Investigation of the cell size effect on the mechanical properties of the microlattice dome reveals that a larger cell size contributes more to the weight-specific stiffness and energy absorption capability at a given overall volume fraction constraint. The topology optimization and construction methods described in this paper are universal and can be used for the further development of ultralight, ultrastiff structures with arbitrary macro shapes with microlattices as constituent units.