There is a growing need for high-performance surfboards, which leads to innovations in terms of composite materials and internal structures. Within this framework, the company WYVE (Anglet, France) proposes surfboards with bio-inspired 3D-printed cores. This study investigates three surfboards with different internal structures in order to build and compare digital twins of their flexural behavior. The first is a conventional board with a PU foam core, a wooden stringer, and a fiberglass/epoxy laminate. The second board is manufactured by WYVE using fused deposition modeling for the core. It consists of a uniform honeycomb structure with in-situ expanded polylactic acid and is laminated with custom composite layers. The third board is produced using the same process and materials but features a 3D-printed turtle pattern. This study aims to elaborate and compare the digital twins of the flexural behavior of these three surfboards by correlating experimental flexural test results and computational simulations to control the rigidity before printing. The digital twin models showed good agreement with experiments, with mean deviations below 10%. Among the additively manufactured boards, the honeycomb structure was found to be 13% more flexible than the turtle pattern. Once validated, the numerical models enable stiffness prediction through simulations alone. Stiffness can be adjusted by modifying core thickness or material properties without altering the board’s external shape and with minimal impact on weight.
These results demonstrate that, for identical weight, shape, and laminate characteristics, the internal core architecture is a key new factor in determining surfboard stiffness.