Structural Testing of Additive Manufactured Biomimetic Porous Structures Derived From Fire Ant Nest Architectures

Fire ant nest structures are hypothesized to have developed natural collapse-resistant properties through evolutionary processes, motivating investigation of their geometry for potential human applications. Computational studies of these soil-based structures suggest that fire ant nests exhibit hierarchical behavior, with different regions responding uniquely to collapse loading. This paper presents experimental evaluation of these geometries to assess their biomimetic potential when constructed from engineering materials via additive manufacturing. The ant nest geometry previously analyzed using finite element methods was fabricated through fused filament fabrication (FFF) 3D printing with polylactic acid (PLA). These 3D printed representative volume elements with cellular infill were tested under uniaxial compression. Local displacement fields were captured and analyzed using digital image correlation (DIC). Results show that the additively manufactured ant nest structures display similar hierarchical behavior to that observed in analysis with soil. Post-test X-ray computed tomography (CT) inspection revealed that internal deformation occurs primarily through localized buckling of cell walls. Additional X-ray CT scans taken at various levels of compressive strain demonstrate that the local damage of these structures, in the global post-yield regime, of the printed structures resembles that of soil-constructed ant nests. The mechanisms for local collapse and damage in the cellular infill through successive buckling and compaction appear to localize in the same regions where the soils exhibited plastic deformation.