Interpenetrating phase composites with 3D printed triply periodic minimal surface (TPMS) lattice structures

Micro-selective laser melting fabricated triply periodic minimal surface sheet lattice and epoxy interpenetrating phase composites (IPCs) are investigated in this paper. To achieve superior specific energy absorption (SEA) enhancements in the composites, an optimised Schwarz primitive lattice (P-lattice) structure is proposed by redefining the shell opening diameter with a shape parameter. Also, the influences of fabrication directions, along the [100], [110], and [111] lattice directions, on the mechanical responses of the P-lattices and IPCs are presented. Compression results reveal that the modified P-lattices outperform the original P-lattices with superior compressive strength and SEA. The P-lattices also display the lowest strength and SEA along [100] as compared to that of [110] and [111]. The compressive strength and SEA of modified P-lattice along [111] are 123.66% and 64.63% higher than its [100], respectively. As for the IPCs, up to a 52% increase, from the linear addition of the two-component phases has been achieved for SEA. The IPCs also exhibit a superior specific energy absorption of 49.6 J/g, a 1109% improvement from that of the pure lattice, which is attributed to the high strength and large plateau strain of the composites. The simulation results show that the internal energy of both lattice and epoxy in composites is 136% and 21%, respectively, higher than that of single structures due to the interaction effects.