Crack Modes and Toughening Strategies Of Bioinspired 3d Printed Double-Helicoidal Architectures

Abstract

The crack modes and toughening strategies of 3D printed double-helicoidal (DH) composites were fully characterized by performing quasi-static three-point bending experiments and simulations. DH specimens with hard brick and soft adhesive were fabricated with dual-material 3D printing technology while single-helicoidal (SH) specimens were also prepared for comparison. The brittle rigid material and the rubber-like material were selected as the brick and adhesive of the specimens, respectively. First, the crack propagation path of the specimens under three-point bending loading was observed, and the fracture toughness and critical deformation displacements were calculated. The double twisting pattern of DH composite makes cracks deflect along complex deflection paths, resulting in increased energy dissipation required to produce deflected crack surfaces, which delays catastrophic damage. Then, the deformation and interlayer stress distribution under static loading were analyzed by finite element analysis. It was found that the higher and in each layer were responsible for the crack deflection of the DH specimen, which acts as a toughening strategy in the coelacanth-fish-inspired DH structure and will promote the next generation fracture-resistant composite design.

Keywords: 3D printing, Bioinspired double-helicoidal composites, Crack mode, Crack deflection, Toughening strategy