Strengthening and toughening strategies of 3D printed continuous fiber-reinforced composites with bioinspired layered configuration

This paper aims to investigate the strengthening and toughening strategies of 3D-printed continuous fiber-reinforced composites (CFRCs) with a bioinspired layered configuration, characterized by a gradient distribution of matrix materials and sinusoidal architectures of continuous fibers. Experimental results indicate that the bioinspired layered CFRCs demonstrate superior interlayer shear strength (ILSS), stiffness, and energy absorption in short beam shear (SBS) tests, with maximum values of 32.5 MPa, 3842.4 N/mm, and 18.3 J—showing increases of 156 %, 96 %, and 762 % over traditional plane layered PLA (PL-PLA) and 78 %, 20 %, and 169 % over plane layered CFRCs (PL-CFRCs). Further analysis of DIC images at different loading times and CT slices at various positions reveals that the trough and crest structure within bioinspired layered CFRCs highlight distinctive capacities for stress–strain redistribution and damage redistribution. By adjusting the frequencies (ωx and ωy), the hybrid load-bearing effect between troughs and crests can be modulated, elucidating how structural parameters govern mechanical responses. Findings suggest that the integration of the two structures allows high-frequency specimens to achieve greater stability while preserving toughness, thereby achieving both strengthening and toughening effects. This work highlights the promising applications of bioinspired structures in 3D printed CFRCs, offering novel methods to optimize performance while expanding possibilities and flexibility in structural design for engineering applications .