Structural Performance of Additively Manufactured Composite Lattice Structures: Strain Rate, Cell Geometry, and Weight Ratio Effects

The proliferation of ordered cellular structures in industrial and technological applications is justified by their superior mechanical performance, including tunable energy absorption strategies and potential multifunctionality. This research evaluates the mechanical response of composite lattice structures fabricated using vat photopolymerization additive manufacturing process and printable particulate composite materials. Several generations of modified printable resins are prepared by hybridizing flexible resin with varying glass microballoons reinforcement weight percentages. Multifaceted characterization regiments highlight the process–property–performance interrelationship by submitting printed composite structures to quasi-static and impact-loading scenarios combined with digital stills and high-speed photography, respectively. Image analyses of optical and scanning electron micrographs quantify the dimensional accuracy of the composite lattice structures with cylindrical and hexagonal cellular geometries. The mechanical characterization uncovers the effect of cell geometry and reinforcement on the global structural behavior, eliciting differences in load-bearing capacity, local strain developments, and structural densification. Exploratory digital image correlation supports the global structural deformations, revealing their relationship with the developed local strain state within the unit cells. The outcomes of this research elucidate the effect of strain rate, unit cell geometry, and reinforcing ratios on the structural performance of composite lattice structures at the macro- and microstructure levels.