Topology optimization of CFRP hierarchical pyramidal structures fabricated by additive manufacturing

The optimal structural hierarchy was introduced into the conventional pyramidal structure by integrating the homogenization-based topology optimization (HMTO) with elastically isotropic elementary lattices for further improvement of structural efficiency. The mechanical properties and elastic isotropy of representative truss-lattices composed of struts and plate-lattices consisting of closed-cell sheets were firstly evaluated, based on which the equivalent out-of-plane compression modulus of the hierarchical pyramidal structure was theoretically analysed and then compared with experimental and numerical results to systematically clarify the effects of lattice topology on the structural performance. Furthermore, the elementary lattice exhibiting the optimal structural efficiency and elastic isotropy was integrated with HMTO to optimize the out-of-plane compression properties including stiffness and energy absorption capability. The hierarchical pyramidal structure with optimal structural hierarchy achieves 4.8% and 28.2% higher compressive modulus over the conventional pyramidal structure and unoptimized hierarchical pyramidal structure, respectively. The energy absorption capability of optimized and unoptimized hierarchical pyramidal structures is 63.4% and 27.2% higher than that of conventional pyramidal structure without structural hierarchy, respectively. The results obtained from this study indicate that the structural hierarchy introduced via integration of isotropic SC-FCC plate-lattice with HMTO can effectively improve the structural efficiency of hierarchical pyramidal structures.

Automated summary

The study combines homogenization-based topology optimization with elastically isotropic lattice structures to introduce optimal structural hierarchy into conventional pyramidal structures, improving their efficiency and performance. The optimized structure shows higher compressive modulus and energy absorption capability compared to unoptimized and traditional pyramidal structures.