Numerical Analysis on the Quasi‐Static Mechanical Performance of Nacre‐Like <scp>PLA</scp> ‐Composites Prepared by Two‐Material Fused Filament Fabrication

ABSTRACT Inspired by the structures of pearl layers and crayfish exoskeletons, this study developed a two‐material biomimetic sandwich composite featuring an interlayer helical stacking structure. Its core consists of a PLA/GF honeycomb structure, while the filler is a PLA/CB composite material. Through experimental testing, finite element simulations, and mesoscopic structural observations, we systematically investigated the effects of interlayer rotation angle, lateral displacement, and relative gap ratio on the four‐point bending performance of the structure. Experimental results indicate that lateral displacement between layers is the key parameter influencing bending strength. At a displacement of 5 mm, the structure achieves optimal load‐bearing capacity by altering crack propagation pathways. Mesoscopic morphology observations confirm that cracks preferentially initiate at the heterogeneous interfaces between PLA/GF and PLA/CB. The finite element simulations effectively identify primary stress concentration zones that correlate with experimentally observed failure initiation sites, establishing a mechanistic link between the elastic stress landscape and the structural weak points. This study highlights the critical role of finite element simulation in linking macro‐performance, meso‐damage, and meso‐interface behavior, providing theoretical support and methodological foundations for multi‐material co‐design and performance optimization.