Continuous fiber-reinforced 2.5D hybrid lattice structures with superior compression performance via self-supporting suspension printing

This paper proposes an innovative class of two-and-a-half dimensional (2.5D) hybrid continuous fiber reinforced lattice structures (CFRLSs) that rationally combine distinct lattice designs to leverage the tensile strength of fibers for achieving superior compression performance. These hybrid structures are fabricated through a self-supporting suspension printing (SSSP) method, which enables the fabrication of suspension structures across substantial gaps through continuous fiber 3D printing (CF-3DP). The compression behavior of the proposed 2.5 D hybrid CFRLSs was optimized by focusing on two key variables in hybridizing the basic lattice along the build direction: composition ratio and distribution strategy. Finite element and analytical models were developed to elucidate their three failure mechanisms and related control strategies. Compared to the conventional single-type structure, i.e., honeycomb design, the proposed hybrid structures show a substantially higher compression performance, with improvements of up to 141.3 % and 330.1 % in specific strength and modulus, respectively, even at a lower density. This hybrid lattice design method based on SSSP opens up new horizons for engineering high-performance CFRLSs with superior compression performance by fully exploiting the design freedom offered by CF-3DP.