Experimental and numerical study of three-point bending test in five different FDM 3D printed PLA core with carbon fiber sandwich structures

Abstract Carbon fiber sandwiched structures with different core shapes have gained remarkable attention in various industries, especially mezzanine structures, because of their divergent mechanical properties and lightweight nature. In this work, the energy absorption capabilities of a carbon fiber sandwich with five different PLA core geometries (i.e., Honeycomb, X-shape, Tubular hollow, Triangular, and Tubular solid) that are manufactured by FDM are explored. The flexural properties of the samples are analyzed by a three-point bending test with the ASTM C393 standard. The sandwich composite with a tubular solid structure withstands a maximum load of 1178 N and has the highest flexural strength of 100.97 MPa and energy absorption of 9.95 J due to the long plateau region observed in the three-point bending test compared to other sandwich structures. X-shape core found a maximum load of 760 N in a short period of time due to the densification curve. Each core unit cell behaves differently in the force-displacement curve. It was found that the triangle core and tubular hollow core unit cell failed individually in the final deformation phase compared to other structures, individual cell failure affects the flexural stiffness. ANSYS Workbench 2024 was used for validating the deformation behavior of carbon fiber sandwich structures with five different cores and compared it with experimental results.