Mechanical Behavior and Fractal Analysis of <scp>3D</scp> Printing Biomimetic Elliptical Porous <scp>PLA</scp> Structures

ABSTRACT Inspired by lobster claw Bouligand structures, three elliptical PLA porous structures—vertical (V‐EPS), horizontal (H‐EPS), and spiral (S‐EPS)—were fabricated via FDM. Their mechanical responses and stress distributions were systematically assessed via compression and bending tests and FEA. Results show distinct advantages: V‐EPS achieved highest compressive strength and energy absorption; H‐EPS demonstrated superior bending strength. Notably, S‐EPS exhibited the best overall performance, especially in bending energy absorption, despite a 26.9% lower compressive peak stress than V‐EPS. This superiority stems from its unique deformation mechanisms, including efficient stress redistribution and significant crack deflection. Fractal geometry quantified fracture complexity using MATLAB‐derived fractal dimension ( D ). Higher D values indicate more tortuous cracks, and quantitative analysis confirmed a positive correlation between D and macroscopic fracture toughness, implying greater crack complexity enhances energy dissipation. These findings provide a biomimetic design framework for lightweight structures optimized for specific loading modes (compression or bending). Combining biomimicry, PLA materials, and AM offers an effective strategy for lightweight sustainable solutions in aerospace.