Flexural Behavior of 3D‐Printed Porous Bouligand‐Structured Polymers: Influence of Pitch Angle and Porosity

Natural helicoidal cellular structures demonstrate significant potential for leading future developments of materials that are both light in weight and demonstrate resistance to impact damage, enduring damage, and enhanced energy dissipation. We have yet to fully understand how controlled porosity affects the mechanical response of these structures. This study examines the bending response of 3D‐printed porous Bouligand‐structured polymers (PBSPs) inspired by snapping shrimp exoskeletons through experimental tests and finite element modeling. Specimens with varying pitch angles (10°–90°) and fiber spacing (0.5–1.25 mm) were fabricated using stereolithography 3D printing, and then tested under three‐point bending according to ASTM D790‐17. A helicoidal structure with a 30° pitch angle and 0.5 mm fiber spacing achieved 17.8 MPa of flexural strength and 450 MPa flexural modulus, which exceeded the performance of higher porosity counterparts by 15%–20% in both metrics. Changing fiber spacing from 0.5 to 1.25 mm reduced stiffness by 17% and strength by 15%, showcasing the mechanical performance tradeoff due to increased energy dissipation. FEA simulations matched experimental data both qualitatively and quantitatively to a correlation coefficient above 0.91, while stress distribution analysis demonstrated that a medium (30°) pitch angle results in distributed damage and energy dissipation through crack deflection and interfacial shear mechanisms. The fundamental design principles of bioinspired cellular structures uncovered in this study not only facilitate their application in aerospace panels, biomedical implants, and protective systems, but also enable the structural optimization of helicoidal architectures through the manipulation of porosity.